# Calcgrid (remote · tttkmbb.com) Pinned IANA time-zone and finance calculators plus source-traceable China working-day data. - Trust score: 74/100 (medium) - Registry status: active - Liveness: live - Owner verified: no - Last scored: 2026-09-26 ## Components - remote · `tttkmbb.com`: 74/100 (this document), [markdown](https://verifymcp.io/servers/com-tttkmbb-calcgrid/tttkmbb.md), [page](https://verifymcp.io/servers/com-tttkmbb-calcgrid/tttkmbb) ## Channel facts - Endpoint: `https://tttkmbb.com/mcp` - Transports: `streamable-http` - Auth: `none` - Version: `1.7.0` ## Trust breakdown How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog) Scored 2026-09-26. - **Endpoint Security**: 80/100 - The endpoint's TLS certificate is valid, in date, and uses a strong key. - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one. - HTTPS is enforced; there's no plaintext access path. - The HSTS (Strict-Transport-Security) header is present. - DNSSEC check failed: this domain isn't protected by DNSSEC. - **Transport & Reachability**: 100/100 - Verified streamable-http transport via a live MCP handshake. - **Schema Quality & AI Usability**: 77/100 - 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name). - AI-judged instruction clarity (excellent). - Context-footprint check failed: tool/resource definitions use about 23362 tokens (~307/item across 76 items; 50 tools + 26 resources), over budget; trim descriptions and params. - Usage-examples check failed: none of the tools include examples. - **Stability & Change Management**: 3/100 - Stability observed for 1 of 30 days with no destabilising changes; credit accrues until the full window elapses. - **Tool Coverage**: 100/100 - 100% of tools have a non-trivial description (not blank, and not just the tool's name). - 99% of tool parameters carry a description. - Structured output schemas are declared (94% of tools); any adoption earns full credit. - **Tool Safety**: 100/100 - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured. - We read all 50 captured tool definition(s), and no name or description among them implies an irreversible operation. - An AI judge read all 52 captured unit(s) of tool text and found none that tries to manipulate the model reading it. - **Capabilities**: 100/100 - Implements a current MCP spec version (2026-07-28). ## Install ### How do I install the Calcgrid MCP server? Calcgrid is a hosted endpoint at https://tttkmbb.com/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation. ### Claude ```bash claude mcp add --transport http com-tttkmbb-calcgrid 'https://tttkmbb.com/mcp' ``` ### Cursor ```json { "mcpServers": { "com-tttkmbb-calcgrid": { "url": "https://tttkmbb.com/mcp" } } } ``` ### VS Code ```json { "servers": { "com-tttkmbb-calcgrid": { "type": "http", "url": "https://tttkmbb.com/mcp" } } } ``` ### Codex ```toml [mcp_servers.com-tttkmbb-calcgrid] url = "https://tttkmbb.com/mcp" ``` ### opencode ```json { "$schema": "https://opencode.ai/config.json", "mcp": { "com-tttkmbb-calcgrid": { "type": "remote", "url": "https://tttkmbb.com/mcp", "enabled": true } } } ``` ### OpenClaw ```bash openclaw mcp add com-tttkmbb-calcgrid --url 'https://tttkmbb.com/mcp' --transport streamable-http ``` ### Hermes ```yaml mcp_servers: com-tttkmbb-calcgrid: url: "https://tttkmbb.com/mcp" ``` ### Netclaw ```json { "McpServers": { "com-tttkmbb-calcgrid": { "Transport": "http", "Url": "https://tttkmbb.com/mcp" } } } ``` ### Vellum ```bash assistant mcp add com-tttkmbb-calcgrid -t streamable-http -u 'https://tttkmbb.com/mcp' ``` ### Other ```json { "mcpServers": { "com-tttkmbb-calcgrid": { "type": "http", "url": "https://tttkmbb.com/mcp" } } } ``` The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs. ## Changelog Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims. ### 2026-09-26 (score 74, 0) - [security] The server rewrote its instructions, which are the text every model session reads - [security] Tool “convert_time_zone” rewrote its description, which is the text the model reads - [security] Tool “run_calculator” rewrote its description, which is the text the model reads - [security] Tool “search_calculators” rewrote its description, which is the text the model reads - [functional improvement] Stability: unverified → 0.03 - [functional] New resource “iana-tzdb-2026d” - [functional] New resource “iana-tzdb-index” - [functional] New resource “local-time-resolver” - [functional] New resource “time-zone-transitions” - [functional] Server version: 1.6.2 → 1.7.0 - [functional] Server version: 1.6.1 → 1.6.2 - [functional] New tool “list_time_zone_transitions” - [functional] New tool “resolve_local_time” - [cosmetic] “convert_time_zone” added an optional parameter “resolution_policy” ### 2026-09-25 (score 74) First indexed and scored. ## MCP tools (50) ### `search_calculators` (~155 tokens) Search calculators Use this when a user needs a deterministic calculation but none of the dedicated tools clearly matches and the calculator_id is unknown. Search 535 calculators from the complete task in English or Chinese, then call run_calculator with the top matching calculator_id and returned input_hints. Do not use this for trivial arithmetic, live data, writing tasks, or when a dedicated typed tool already matches. This tool only discovers; it does not calculate. Input parameters: - `category` (string): Optional category id to restrict results. - `limit` (integer) - `query` (string, required): The complete user task, including known values and units; for example 'compound interest on 15000 at 4.8% monthly for 12 years'. Output parameters: - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `success` (boolean) - `timestamp` (string) ### `list_calculators` (~118 tokens) List calculators List all calculators, optionally filtered by category id (finance, health, fitness, math, geometry, statistics, conversion, physics, chemistry, everyday, food, construction, business, time, medical, engineering, weather, investing, developer, energy, photography, science, gaming, lunar, yijing). Returns calculator_id, name, description, use_when and required inputs for each. Use it to browse a whole category; use search_calculators for keyword lookup. Does not perform calculations. Input parameters: - `category` (string): Category id. ### `list_calculator_categories` (~39 tokens) List categories List the calculator categories with id, name, description and calculator count. Use it to orient before list_calculators. Does not perform calculations. ### `get_calculator_schema` (~110 tokens) Get calculator schema Use this only after search_calculators when its input_hints do not resolve a range, enum or optional-field question. Return the full input/output schema, formula, sources, examples and limitations for one calculator. Do not call it when the search result already supplies enough input detail; call run_calculator instead. This tool only describes and does not calculate. Input parameters: - `calculator_id` (string, required): Exact calculator_id returned by search_calculators; for example 'bmi' or 'compound-interest'. Output parameters: - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `success` (boolean) - `timestamp` (string) ### `run_calculator` (~159 tokens) Run a calculator Use this when the user needs one of Calcgrid's 535 deterministic calculators and no dedicated typed tool covers it. Call it immediately after search_calculators once calculator_id and input_hints are known; do not stop at search or schema discovery. Do not use it for trivial arithmetic, live rates or unrelated tasks. Returns typed values with units, formula, sources, freshness and timestamp; validation errors identify the field and a repair hint. Input parameters: - `calculator_id` (string, required): Exact calculator_id from search_calculators; for example 'compound-interest'. - `inputs` (object, required): Parameter names and values from search_calculators input_hints or get_calculator_schema. Use numbers as numbers, ISO dates as YYYY-MM-DD and lists as arrays. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `convert_units` (~160 tokens) Convert units Use this when the user asks to convert a numeric value between units of the same physical quantity: length, mass, temperature, area, volume, speed, time, data, energy, pressure, power, angle, fuel economy, force, frequency, density or torque. Unit symbols and common names are accepted. Do not use this for currency, live exchange rates or cross-quantity conversions that require density. Returns the converted value, detected quantity, exact factor and a conversion table. Input parameters: - `from_unit` (string, required): Source unit symbol or name, e.g. 'mi', 'miles', '°C'. - `to_unit` (string, required): Target unit symbol or name, e.g. 'km'. - `value` (number, required): Value to convert. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `list_units` (~59 tokens) List units List every unit symbol supported by convert_units, grouped by quantity, with names. Use it when a unit symbol is rejected with UNKNOWN_UNIT. Does not convert anything. Input parameters: - `quantity` (string): Optional quantity id to filter (e.g. 'length'). ### `check_china_working_day` (~371 tokens) Mainland China Working Day Checker Use this when you need to know whether a specific 2024-2026 date is a working day in mainland China, especially around Spring Festival, National Day or another adjusted holiday. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need a Hong Kong, Macao, Taiwan, local minority, school, employer, bank-settlement or stock-exchange calendar, or a year outside 2024-2026. What it computes: Checks whether a date is an official national working day in mainland China, including weekend makeup workdays (调休上班) and multi-day holiday periods from State Council notices. Example user requests: Is Sunday 2026-01-04 an official working day in mainland China? | 2026年9月20日是休息日还是调休上班？ | Will mainland China offices normally work on 2026-02-18? Inputs: date (date). Outputs: date, weekday, is_working_day, day_type, holiday_name, holiday_name_zh, status_basis, jurisdiction, source_document_id, source_published_at, source_url, dataset_version, coverage_start, coverage_end. Formula: adjusted weekend workday override → working; else official holiday-period override → non-working; else Monday-Friday → working; Saturday-Sunday → non-working Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/china-working-day with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/china-working-day.md Input parameters: - `date` (string, required): Mainland China civil date (YYYY-MM-DD), within 2024-2026. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `add_china_working_days` (~419 tokens) Add Mainland China Working Days Use this when you need a deadline or settlement date a stated number of mainland China national working days before or after a 2024-2026 date. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need calendar days, a sector-specific settlement calendar, a local holiday calendar, or a result outside the 2024-2026 coverage. What it computes: Adds or subtracts official mainland China working days, skipping holiday periods and ordinary weekends while counting State Council-designated weekend makeup workdays. Example user requests: What date is 5 China working days after 2026-09-24, accounting for Mid-Autumn and National Day? | 从2026年9月18日起往后数5个中国工作日是哪天？ | Subtract 10 official mainland China business days from 2026-03-02. Inputs: start_date (date); working_days (integer, working days). Outputs: start_date, result_date, result_weekday, result_is_working_day, working_days_added [working days], calendar_days_elapsed [days], non_working_days_skipped [days], adjusted_workdays_counted, source_document_ids, dataset_version, coverage_start, coverage_end. Formula: move one calendar day at a time in sign(working_days); decrement the remaining count only when is_working_day(date) is true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/china-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/china-add-working-days.md Input parameters: - `start_date` (string, required): Starting mainland China civil date (YYYY-MM-DD), within 2024-2026. - `working_days` (integer, required): Signed number of official working days to add; the start date is excluded when non-zero. Negative values move backward. Unit: working days. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `count_china_working_days` (~476 tokens) Mainland China Working Days Between Dates Use this when you need the number of official mainland China working days in a 2024-2026 date range for an SLA, payroll, project or delivery estimate. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need only elapsed calendar days, another jurisdiction, an industry-specific settlement calendar, or dates outside 2024-2026. What it computes: Counts official mainland China working and non-working days in a date range using State Council holiday periods and weekend makeup workdays rather than a simple Monday-Friday rule. Example user requests: How many official China working days are there from 2026-09-18 through 2026-09-25, inclusive? | 计算2026年国庆节前后这段日期中实际需要上班的天数，要包含调休周末。 | Count mainland China business days between 2025-01-24 and 2025-02-10. Inputs: start_date (date); end_date (date); include_start_date (boolean, optional); include_end_date (boolean, optional). Outputs: normalized_start_date, normalized_end_date, working_days [working days], non_working_days [days], calendar_days_counted [days], adjusted_workdays_counted, holiday_dates_counted [days], source_document_ids, dataset_version, coverage_start, coverage_end. Formula: for each included date: working_days += is_working_day(date); non_working_days += not is_working_day(date) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/china-working-days-between with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/china-working-days-between.md Input parameters: - `end_date` (string, required): Last date of the range (YYYY-MM-DD), within 2024-2026. Earlier dates are normalized and reported in a note. - `include_end_date` (boolean): Whether end_date participates in the count. - `include_start_date` (boolean): Whether start_date participates in the count. - `start_date` (string, required): First date of the range (YYYY-MM-DD), within 2024-2026. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `convert_solar_to_lunar` (~578 tokens) Lunar Calendar Converter (农历) Use this when you need the Chinese lunar date, ganzhi day/month/year, zodiac year or current solar term for a given Gregorian date (defaults to today). Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you start from a lunar date and need the Gregorian date (use lunar-to-solar), need a person's zodiac with the 立春 boundary option (use chinese-zodiac), or need the astronomical moon phase (use moon-phase). What it computes: Converts a Gregorian date to the Chinese lunisolar calendar (农历 nongli): lunar year, month (with leap-month flag), day, the sexagenary stems and branches (干支 ganzhi) of year, month and day, zodiac animal, nayin (纳音), the current 24-solar-term period and any traditional festival on that day. Example user requests: Convert 2026-09-25 to the Chinese lunar calendar and say whether it is a leap month. | 把 2025-07-25 换成农历，并给出干支和节气。 | Which Chinese lunar festival falls on this Gregorian date? Inputs: date (date, optional). Outputs: lunar_year, lunar_month, is_leap_month, lunar_day, lunar_date_chinese, lunar_date_text, month_name, day_name, month_days, leap_month_this_year, year_ganzhi, year_ganzhi_pinyin, year_english, zodiac, nayin_year, month_ganzhi, month_ganzhi_pinyin, day_ganzhi, day_ganzhi_pinyin, weekday, current_solar_term, next_solar_term, days_to_next_term [days], is_solar_term_day, festival, julian_day_number. Formula: lunar month = interval between successive new moons (instants at 120° E, UTC+8); month 11 contains the winter solstice; a leap month is the first month without a major solar term (中气) in a 13-month solstice-to-solstice suite; year_ganzhi index = (lunar_year − 4) mod 60; day_ganzhi index = (JDN + 49) mod 60; month branch = 寅 from 立春, one branch per odd solar term Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/lunar-calendar-converter with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.… Input parameters: - `date` (string): Civil date in China Standard Time (UTC+8), 1900–2100; defaults to the current UTC date. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `convert_lunar_to_solar` (~516 tokens) Lunar to Solar Date Converter Use this when you know a lunar date such as 八月十五 or 闰六月初一 of a given lunar year and need the Gregorian date (e.g. for a lunar birthday or festival). Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you start from a Gregorian date (use lunar-calendar-converter), or you want every festival of a year at once (use chinese-festivals). What it computes: Converts a Chinese lunar calendar date (year, month, leap-month flag, day) to the Gregorian date, reporting the weekday, the day's ganzhi (干支) and the length of that lunar month, and validating that the leap month and day exist in that year. Example user requests: What Gregorian date is lunar 2026 month 8 day 15? | 2025 年农历闰六月初一对应公历哪一天？ | Convert a Chinese lunar birthday to its Gregorian date and verify the leap-month flag. Inputs: lunar_year (integer); lunar_month (integer); is_leap_month (boolean, optional); lunar_day (integer). Outputs: gregorian_date, weekday, day_ganzhi, month_days, lunar_date_chinese, month_name, year_ganzhi, zodiac, julian_day_number, leap_month_note. Formula: JDN = start of the lunar month (new-moon day at UTC+8) + lunar_day − 1; month numbering per GB/T 33661-2017 (month 11 contains the winter solstice; leap month = first month without a 中气) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/lunar-to-solar with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/lunar/lunar-to-solar.md Input parameters: - `is_leap_month` (boolean): true when the date is in the intercalary month of that number (only valid in years that have that leap month). - `lunar_day` (integer, required): Day of the lunar month, 1–30 (day 30 exists only in 30-day months). - `lunar_month` (integer, required): Lunar month number 1 (正月) to 12 (腊月). - `lunar_year` (integer, required): Lunar year number (the year that starts at that year's Chinese New Year), 1900–2100. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `list_solar_terms` (~435 tokens) 24 Solar Terms Calculator (二十四节气) Use this when you need the date or time of 立春, 清明, 夏至, 冬至 or any other solar term in a given year, or the full 24-term table. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only need the term that a specific date falls in (use lunar-calendar-converter), or you need sunrise/sunset times (use sunrise-sunset). What it computes: Lists the 24 solar terms (节气 jieqi) of a Gregorian year with their exact instants: the moments the Sun's apparent longitude reaches multiples of 15°, computed astronomically and shown in a chosen UTC offset (China Standard Time by default). Example user requests: List all 24 solar terms for 2027 in UTC+8. | 2026 年立春和冬至的准确时间是什么？ | When is Qingming this year in China Standard Time? Inputs: year (integer); utc_offset_hours (number, h, optional). Outputs: terms, lichun_date, spring_equinox, summer_solstice, autumn_equinox, winter_solstice, year_ganzhi, suishou_note, utc_offset. Formula: term instant: apparent geocentric solar longitude λ(JDE) = k·15° for k = 0 (春分) … 23 (惊蛰), solved by Newton iteration; UT = TT − ΔT; local time = UT + utc_offset_hours Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/solar-terms with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/lunar/solar-terms.md Input parameters: - `utc_offset_hours` (number): Fixed UTC offset in hours for the local date-times (8 = China Standard Time; 9 = Japan/Korea; 5.5 = India). Unit: h. - `year` (integer, required): Gregorian calendar year (1900–2100). Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `resolve_local_time` (~420 tokens) IANA Local Time Resolver Use this when you must safely turn a named-zone local time into an instant, validate a scheduled time around a daylight-saving transition, or preserve every possible interpretation instead of silently choosing one. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the input already includes a numeric UTC offset or Z, the task only needs the current clock time, or latitude/longitude must first be mapped to a zone. What it computes: Resolves a local wall-clock time with pinned IANA tzdb 2026d. Returns every valid UTC candidate for a repeated fall-back time, or the exact gap and shift-forward suggestion for a nonexistent spring-forward time. Example user requests: Resolve 2026-11-01 01:30 in America/New_York and return both UTC candidates. | Does 2026-03-08 02:30 exist in New York? Show the DST gap. | 判断 Australia/Adelaide 的 2026-10-04 02:30 是否存在，并给出时区数据版本。 Inputs: local_datetime (string); time_zone (string). Outputs: local_datetime, time_zone, resolved_zone_id, status, candidate_count, candidates, gap, related_transition, previous_transition, next_transition, tzdb_version, dataset_version, source_url, source_sha256, coverage_note. Formula: for each zone offset o: candidate_utc = local_wall_time + o; keep candidates whose active offset at candidate_utc equals o Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/local-time-resolver with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/time/local-time-resolver.md Input parameters: - `local_datetime` (string, required): Wall-clock date and time without Z or a numeric offset; it will be interpreted only in time_zone. - `time_zone` (string, required): IANA zone identifier present in tzdb 2026d. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `list_time_zone_transitions` (~424 tokens) IANA Time Zone Transition List Use this when you need the next or historical daylight-saving/offset changes for scheduling, payroll, travel, audits or a regression test, with a specific reproducible tzdb version. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only need to convert one ordinary date-time, need legal advice about a jurisdiction's time law, or need changes announced after this pinned release. What it computes: Lists every UTC-offset transition for one IANA zone and date range using pinned tzdb 2026d, including the local boundaries, offsets, abbreviations and whether the clock creates a gap or overlap. Example user requests: List every 2026 UTC-offset transition in America/New_York with local boundaries. | When does Australia/Adelaide change clocks between 2026-01-01 and 2027-01-01? | 列出 Europe/London 在 2026 年的夏令时转换点、前后偏移和 IANA 数据版本。 Inputs: time_zone (string); start_date (date); end_date (date). Outputs: time_zone, resolved_zone_id, start_date, end_date, transition_count, transitions, tzdb_version, dataset_version, source_url, source_sha256, coverage_note. Formula: select zone transition instants whose local boundary before or after lies inside [start_date, end_date] Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/time-zone-transitions with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/time/time-zone-transitions.md Input parameters: - `end_date` (string, required): Last local calendar date to inspect; ranges may not exceed 3,660 days. - `start_date` (string, required): First local calendar date to inspect (1900-01-01 through 2100-12-31). - `time_zone` (string, required): IANA zone identifier present in tzdb 2026d. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `convert_time_zone` (~578 tokens) Time Zone Converter Use this when you need to know what time an event scheduled in one city corresponds to in another city or in UTC on a specific date. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need the same instant in many zones at once (use world-clock), an epoch value (use unix-timestamp), or the elapsed time between two clock times (use time-duration). What it computes: Converts a wall-clock date and time between IANA zones using pinned tzdb 2026d. It reports both offsets, the UTC instant, date changes, the source-time status and every candidate UTC instant when the input falls in a repeated hour. Example user requests: Convert 2027-01-15 09:00 America/New_York to Australia/Adelaide and show both dates. | 把 2026-07-15 09:00 纽约时间换成阿德莱德时间。 | What UTC instant corresponds to 2026-10-04 01:45 in Australia/Adelaide? Inputs: date (date, optional); time (string); from_zone (string); to_zone (string); resolution_policy (enum, optional). Outputs: converted_date, converted_time, converted_datetime, converted_weekday, from_utc_offset, to_utc_offset, from_abbreviation, to_abbreviation, utc_datetime, day_difference [days], time_difference_hours [h], source_time_status, source_candidate_utc_datetimes, applied_resolution_policy, tzdb_version, dataset_version, source_url, source_sha256. Formula: utc = date + time − offset_from(date, time); converted = utc + offset_to(utc); time_difference_hours = (offset_to − offset_from) / 60 Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/time-zone-converter with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/time/time-zone-converter.md Input parameters: - `date` (string): Calendar date of the source time in from_zone (YYYY-MM-DD); defaults to the current UTC date. - `from_zone` (string, required): IANA time zone of the source time, e.g. Australia/Adelaide, Europe/Berlin or UTC. - `resolution_policy` (string): How to handle a repeated or nonexistent source wall time. reject is safest; earlier/later choose a repeated-time candidate; shift_forward moves a skipped time by the DST gap. - `time` (string, required): Wall-clock time in from_zone, 24-hour HH:MM (seconds optional). - `to_zone` (string, required): IANA time zone to convert to, e.g. America/New_York or Asia/Tokyo. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_loan_payment` (~501 tokens) Loan Payment Calculator Use this when you need the monthly payment or total interest cost of an auto, personal, student or other fixed-rate installment loan given its amount, APR and term. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need property tax, insurance and HOA in the payment (use mortgage-payment), or you know the payment and want the payoff time (use debt-payoff). What it computes: Computes the level monthly payment of a fully amortizing fixed-rate loan from principal, annual rate and term, plus the total paid and total interest over the life of the loan. Example user requests: For a 100000 loan at 6% fixed for 5 years, calculate the monthly payment and total interest. | What will I pay each month on a 420000 loan at 6.15% for 25 years? | 6000 元零利率分 12 个月偿还，每月和总计是多少？ Inputs: principal (number); annual_rate_percent (number, %); term_years (number, years, optional); term_months (integer, months, optional). Outputs: monthly_payment, number_of_payments, total_payment, total_interest, payoff_summary. Formula: i = annual_rate_percent / 1200; n = 12·term_years + term_months; monthly_payment = principal × i / (1 − (1 + i)^−n); if i = 0, monthly_payment = principal / n. total_payment = monthly_payment × n; total_interest = total_payment − principal. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/loan-payment with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/loan-payment.md Input parameters: - `annual_rate_percent` (number, required): Nominal annual rate in percent; the monthly rate is this / 12. 0 is allowed for interest-free loans. Unit: %. - `principal` (number, required): Amount borrowed. - `term_months` (integer): Additional months of term (e.g. term_months=60 alone for a 5-year auto loan). Unit: months. - `term_years` (number): Loan term in years; fractional values allowed. Added to term_months when both are given. Unit: years. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `compare_loans` (~670 tokens) Loan Comparison Calculator Use this when you have two loan or mortgage quotes with different rates, terms or fees for the same amount and want the payments and lifetime costs side by side. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you are replacing an existing loan (use refinance-break-even), only need one loan's payment (use loan-payment), or will sell or repay early (this compares full-term costs and ignores the time value of money). Informational; not financial advice. What it computes: Compares two fixed-rate, fully amortizing loan offers for the same amount: the level monthly payment, total interest, up-front fees and total cost (interest + fees) of each, and which offer costs less over its full term. Example user requests: Compare a 300000 loan at 6% for 30 years with 3000 in fees against 5.5% for 15 years with 5000 in fees. | Which of these two fixed-rate offers has the lower lifetime interest and fees? | 同样贷款30万元，方案A年利率6%期限30年，方案B年利率5.5%期限15年，比较月供和总成本。 Inputs: loan_amount (number); rate_a_percent (number, %); term_a_years (number, years); fees_a (number, optional); rate_b_percent (number, %); term_b_years (number, years); fees_b (number, optional). Outputs: payment_a, payment_b, total_interest_a, total_interest_b, total_cost_a, total_cost_b, cheaper_loan, monthly_payment_difference, total_cost_difference, comparison, summary. Formula: For each loan: i = rate/1200, n = 12 × term_years, payment = loan_amount × i / (1 − (1 + i)^−n) (loan_amount / n if i = 0); total_interest = payment × n − loan_amount; total_cost = total_interest + fees. cheaper_loan = the loan with the lower total_cost; monthly_payment_difference = payment_a − payment_b; total_cost_difference = total_cost_a − total_cost_b Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/loan-comparison with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/loan-comparison.md Input parameters: - `fees_a` (number): Up-front fees of loan A (origination, points, closing costs), paid separately rather than financed. - `fees_b` (number): Up-front fees of loan B. - `loan_amount` (number, required): Amount borrowed under both offers. - `rate_a_percent` (number, required): Annual nominal rate of loan A in percent; the monthly rate is this / 12. Unit: %. - `rate_b_percent` (number, required): Annual nominal rate of loan B in percent. Unit: %. - `term_a_years` (number, required): Term of loan A in years (fractions allowed; rounded to whole months). Unit: years. - `term_b_years` (number, required): Term of loan B in years. Unit: years. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_compound_interest` (~498 tokens) Compound Interest Calculator Use this when you need to project a savings account, certificate of deposit or investment balance from a starting amount, an annual rate, a term and optional monthly deposits. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when interest is not reinvested (use simple-interest), you need the deposit required to hit a target (use savings-goal), or you are repaying a loan (use loan-payment). What it computes: Computes the future balance of a principal earning compound interest at a chosen compounding frequency, optionally with a fixed deposit at the end of every month, and splits the result into contributions and interest. Inputs: principal (number); annual_rate_percent (number, %); years (number, years); compounding_frequency (enum, optional); monthly_contribution (number, optional). Outputs: final_balance, total_contributions, total_interest, effective_annual_rate_percent [%], growth_multiple. Formula: A = principal × (1 + r/n)^(n·years) with r = annual_rate_percent/100 and n periods per year. Contributions: i_m = (1 + r/n)^(n/12) − 1, m = 12·years, FV_contrib = monthly_contribution × ((1 + i_m)^m − 1) / i_m (m × contribution when r = 0). final_balance = A + FV_contrib. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/compound-interest with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/compound-interest.md Input parameters: - `annual_rate_percent` (number, required): Nominal annual rate (APR) in percent; 5 means 5 %. Unit: %. - `compounding_frequency` (string): How often interest is credited: n = 1, 2, 4, 12, 52 or 365 periods per year. - `monthly_contribution` (number): Optional fixed deposit made at the end of every month, compounded at the effective monthly rate implied by compounding_frequency. - `principal` (number, required): Starting amount deposited or invested, in any currency. - `years` (number, required): Length of the investment in years; fractional years allowed (2.5 = 30 months). Unit: years. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_mortgage_payment` (~554 tokens) Mortgage Payment Calculator Use this when you want the monthly cost of buying a home with a fixed-rate mortgage, including escrowed taxes and insurance, or the total interest over the loan. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the loan is adjustable-rate or interest-only, or you only need the payment on a plain loan amount (use loan-payment). What it computes: Computes the monthly principal-and-interest payment of a fixed-rate mortgage from home price, down payment, rate and term, then adds property tax, home insurance and HOA dues to give the full monthly housing payment and lifetime interest. Inputs: home_price (number); down_payment (number, optional); annual_rate_percent (number, %); term_years (number, years, optional); annual_property_tax (number, optional); annual_home_insurance (number, optional); monthly_hoa (number, optional). Outputs: loan_amount, loan_to_value_percent [%], monthly_principal_and_interest, monthly_property_tax, monthly_insurance, monthly_hoa_fee, total_monthly_payment, number_of_payments, total_interest, total_of_payments, payoff_summary. Formula: loan_amount = home_price − down_payment; i = annual_rate_percent / 1200; n = 12·term_years; P&I = loan_amount × i / (1 − (1 + i)^−n) (loan_amount / n if i = 0); total_monthly_payment = P&I + annual_property_tax/12 + annual_home_insurance/12 + monthly_hoa. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/mortgage-payment with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/mortgage-payment.md Input parameters: - `annual_home_insurance` (number): Yearly homeowners insurance premium; one twelfth is added monthly. - `annual_property_tax` (number): Yearly property tax; one twelfth is added to the monthly payment. - `annual_rate_percent` (number, required): Fixed note rate in percent; the monthly rate is this / 12. Unit: %. - `down_payment` (number): Cash paid up front; loan_amount = home_price − down_payment. For 20 % of a 250,000 home enter 50000. - `home_price` (number, required): Purchase price of the property. - `monthly_hoa` (number): Monthly homeowners-association or condo fee. - `term_years` (number): Loan term in years (30 and 15 are the common US terms). Unit: years. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_tip` (~316 tokens) Tip Calculator Use this when you need to add a gratuity to a restaurant, delivery or service bill and optionally divide the total among several people. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when people pay for different items or unequal shares (use bill-split), or you need to add sales tax rather than a tip (use sales-tax). What it computes: Computes the tip from a bill amount and tip percentage, the total including tip, and the per-person share when the bill is split evenly. Inputs: bill_amount (number); tip_percent (number, %, optional); split_between (integer, optional). Outputs: tip_amount, total_amount, total_per_person, tip_per_person, bill_per_person. Formula: tip_amount = bill_amount × tip_percent / 100; total_amount = bill_amount + tip_amount; per person = value / split_between Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/tip with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/tip.md Input parameters: - `bill_amount` (number, required): Amount on the bill before tip (pre- or post-tax, as you prefer to tip). - `split_between` (integer): How many people share the bill equally. - `tip_percent` (number): Gratuity as a percent of bill_amount. US restaurant custom is 15–20 %. Unit: %. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_amortization_schedule` (~584 tokens) Amortization Schedule Calculator Use this when you need to see how each payment splits into principal and interest over the life of a mortgage or loan, the balance at the end of each year, or the effect of paying extra every month. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only need the payment amount (use loan-payment or mortgage-payment), or you know the payment and want the payoff time of a revolving balance (use debt-payoff). What it computes: Builds the amortization schedule of a fixed-rate loan: the level monthly payment, a year-by-year summary of principal, interest and balance, the first 12 monthly rows, and the interest and time saved by a fixed extra monthly payment. Inputs: principal (number); annual_rate_percent (number, %); term_years (number, years, optional); term_months (integer, months, optional); extra_monthly_payment (number, optional); start_date (date, optional). Outputs: monthly_payment, number_of_payments, payoff_months [months], payoff_time, payoff_date, total_interest, total_paid, scheduled_total_interest, interest_saved, months_saved [months], first_month_interest, first_month_principal, yearly_summary, first_12_months. Formula: i = annual_rate_percent / 1200; n = 12·term_years + term_months; monthly_payment = principal × i / (1 − (1 + i)^−n) (principal / n if i = 0). Each month: interest = balance × i; principal_paid = monthly_payment + extra_monthly_payment − interest (capped at the balance); balance −= principal_paid, until the balance is 0. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/amortization-schedule with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/amortization-schedule.md Input parameters: - `annual_rate_percent` (number, required): Fixed nominal annual rate in percent; the monthly rate is this / 12. Unit: %. - `extra_monthly_payment` (number): Optional fixed amount paid on top of the scheduled payment every month, applied to principal. - `principal` (number, required): Amount borrowed. - `start_date` (string): Optional loan origination date (YYYY-MM-DD); the first payment is due one month later and payoff_date is reported. - `term_months` (integer): Additional months of term (e.g. term_months=60 alone for a five-year loan). Unit: months. - `term_years` (number): Loan term in years; added to term_months when both are given. Total term is limited to 40 years. Unit: years. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_bmi` (~297 tokens) BMI Calculator Use this when you need an adult's BMI, its WHO/CDC weight category, or the weight range that corresponds to a normal BMI (18.5–24.9) for a given height. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the person is under 20 years old (children need age- and sex-specific BMI percentiles), or you need body-fat percentage (use body-fat) or calorie needs (use bmr / tdee). What it computes: Computes body mass index (BMI) from weight and height and classifies it with the WHO adult categories, plus the healthy weight range for that height. Inputs: weight_kg (number, kg); height_cm (number, cm). Outputs: bmi [kg/m²], category, healthy_weight_min_kg [kg], healthy_weight_max_kg [kg], prime. Formula: BMI = weight_kg / (height_cm / 100)² Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/bmi with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/health/bmi.md Input parameters: - `height_cm` (number, required): Standing height in centimetres. Unit: cm. - `weight_kg` (number, required): Body weight in kilograms. Unit: kg. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_bmr` (~443 tokens) BMR Calculator Use this when you need resting daily calorie needs for an adult from sex, weight, height and age, as a base for diet or TDEE calculations. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need total daily calories including activity (use tdee), the person is a child, pregnant, or has very high muscle mass (use a body-fat based equation such as Katch-McArdle instead). What it computes: Estimates basal metabolic rate (calories burned at complete rest per day) with the Mifflin-St Jeor equation, and also reports the revised Harris-Benedict estimate. Inputs: sex (enum); weight_kg (number, kg); height_cm (number, cm); age_years (number, years). Outputs: bmr_kcal_per_day [kcal/day], harris_benedict_kcal_per_day [kcal/day], bmr_kj_per_day [kJ/day]. Formula: Mifflin-St Jeor: BMR = 10·weight_kg + 6.25·height_cm − 5·age_years + 5 (male) or − 161 (female). Harris-Benedict (1984): male 88.362 + 13.397·W + 4.799·H − 5.677·A; female 447.593 + 9.247·W + 3.098·H − 4.330·A. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/bmr with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/health/bmr.md Input parameters: - `age_years` (number, required): Age in years (adults only). Unit: years. - `height_cm` (number, required): Height in centimetres. Unit: cm. - `sex` (string, required): Biological sex used to select the formula coefficients. - `weight_kg` (number, required): Body weight in kilograms. Unit: kg. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_tdee` (~411 tokens) TDEE Calculator Use this when you need daily maintenance calories for an adult, or calorie targets for a mild/standard deficit or surplus. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the person is a child, pregnant or breastfeeding, or you only need the resting rate (use bmr). What it computes: Estimates total daily energy expenditure from Mifflin-St Jeor BMR and an activity level, and derives calorie targets for maintaining, losing or gaining weight. Inputs: sex (enum); weight_kg (number, kg); height_cm (number, cm); age_years (number, years); activity_level (enum, optional). Outputs: bmr_kcal_per_day [kcal/day], activity_multiplier, tdee_kcal_per_day [kcal/day], mild_loss_kcal_per_day [kcal/day], loss_kcal_per_day [kcal/day], mild_gain_kcal_per_day [kcal/day], gain_kcal_per_day [kcal/day]. Formula: TDEE = BMR(Mifflin-St Jeor) × activity_multiplier; targets = TDEE ± 250 or ± 500 kcal/day Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/tdee with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/health/tdee.md Input parameters: - `activity_level` (string): Weekly exercise level; maps to the standard activity multipliers 1.2 / 1.375 / 1.55 / 1.725 / 1.9. - `age_years` (number, required): Age in years. Unit: years. - `height_cm` (number, required): Height in centimetres. Unit: cm. - `sex` (string, required): Biological sex used to select the formula coefficients. - `weight_kg` (number, required): Body weight in kilograms. Unit: kg. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_running_pace` (~482 tokens) Running Pace Calculator Use this when you know a distance and the time it took (or a target time) and need the pace, the equivalent speed, or the time that pace gives over standard race distances. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you want a realistic prediction of a longer race from a shorter one (pace slows with distance; use race-time-predictor), or you only need to convert between pace and speed units (use pace-converter). What it computes: Computes running pace in min/km and min/mile and speed in km/h and mph from a distance and elapsed time, and projects the finish time for 5 km, 10 km, half marathon and marathon at that constant pace. Inputs: distance (number); distance_unit (enum, optional); time (string). Outputs: pace_min_per_km [min:sec/km], pace_min_per_mile [min:sec/mi], pace_seconds_per_km [s/km], speed_kmh [km/h], speed_mph [mph], distance_km [km], time_5k [h:mm:ss], time_10k [h:mm:ss], time_half_marathon [h:mm:ss], time_marathon [h:mm:ss]. Formula: pace_s_per_km = time_seconds / distance_km; pace_s_per_mile = pace_s_per_km × 1.609344; speed_kmh = 3600 / pace_s_per_km; speed_mph = speed_kmh / 1.609344; time(D) = pace_s_per_km × D for D = 5, 10, 21.0975, 42.195 km Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/running-pace with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/fitness/running-pace.md Input parameters: - `distance` (number, required): Distance covered, in the unit given by distance_unit. - `distance_unit` (string): Unit of the distance input. - `time` (string, required): Elapsed time as h:mm:ss (1:45:00), mm:ss (50:00) or plain minutes (50). Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_percentage` (~373 tokens) Percentage Calculator Use this when you need a percentage of a value, the percentage one value represents of another, or the base value that a part and its percentage imply. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need the percentage change between two values (use percentage-change), a price after a percentage discount (use discount) or a tax amount (use sales-tax). What it computes: Solves the three basic percentage questions (a percentage of a number, what percentage one number is of another, and the whole behind a known part and percentage). Always returns the part, the whole and the percent. Inputs: mode (enum, optional); x (number); y (number). Outputs: result, sentence, part, whole, percent [%]. Formula: percent_of: result = x / 100 × y. is_what_percent: result = x / y × 100. percent_of_what: result = x / (y / 100). In every mode part = percent × whole / 100. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/percentage with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/math/percentage.md Input parameters: - `mode` (string): Which percentage question to solve; x and y take the meaning shown in the label of the chosen mode. - `x` (number, required): First number: the percent (percent_of) or the part (is_what_percent, percent_of_what). Percents are plain numbers, 15 means 15%. - `y` (number, required): Second number: the whole (percent_of, is_what_percent) or the percent (percent_of_what). Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_percentage_change` (~291 tokens) Percentage Change Calculator Use this when you have a starting and an ending value and need the percentage increase or decrease, or a symmetric percent difference between two comparable values. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need a percentage of a number (use percentage), an annualised growth rate over several years (use cagr) or an investment return (use roi). What it computes: Computes the relative change from an old value to a new value as a percentage, the signed absolute change, the new/old ratio and the symmetric percent difference. Inputs: old_value (number); new_value (number). Outputs: change_percent [%], absolute_change, direction, ratio, percent_difference [%]. Formula: change_percent = (new_value − old_value) / |old_value| × 100; percent_difference = |new_value − old_value| / ((|new_value| + |old_value|) / 2) × 100 Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/percentage-change with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/math/percentage-change.md Input parameters: - `new_value` (number, required): Ending value. - `old_value` (number, required): Starting (reference) value. Must not be 0. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `solve_quadratic_equation` (~367 tokens) Quadratic Equation Solver Use this when you need the solutions of a second-degree polynomial equation, or the vertex and discriminant of a parabola y = ax² + bx + c. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the coefficient a is 0 (the equation is linear: x = −c / b), or you need roots of x^n = c for other powers (use nth-root). What it computes: Solves ax² + bx + c = 0 with the quadratic formula, reporting the discriminant, both roots (real, or complex conjugates written as strings), the vertex of the parabola and the sum and product of the roots. Inputs: a (number); b (number); c (number). Outputs: discriminant, nature, root1, root2, roots, vertex_x, vertex_y, sum_of_roots, product_of_roots. Formula: Δ = b² − 4ac; x = (−b ± √Δ) / (2a); for Δ < 0: x = −b/(2a) ± i·√(−Δ)/(2|a|); vertex = (−b/(2a), c − b²/(4a)) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/quadratic-equation with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/math/quadratic-equation.md Input parameters: - `a` (number, required): Coefficient of x². Must not be 0. - `b` (number, required): Coefficient of x. - `c` (number, required): Constant term. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_fraction_arithmetic` (~422 tokens) Fraction Calculator Use this when you need an exact result of an operation on two fractions (e.g. 3/4 + 1/6), including mixed numbers such as 1 1/2, rather than a rounded decimal. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only want to reduce a single fraction or convert it to a decimal or percent (use fraction-simplifier), or you need the least common denominator of several denominators (use gcd-lcm). What it computes: Adds, subtracts, multiplies or divides two fractions, mixed numbers, whole numbers or decimals with exact integer arithmetic, returning the result in lowest terms, as a mixed number and as a decimal, with the intermediate steps. Inputs: fraction_a (string); fraction_b (string); operation (enum, optional). Outputs: result, mixed_number, numerator, denominator, decimal, working. Formula: a/b + c/d = (a·(L/b) + c·(L/d)) / L with L = lcm(b, d), a/b − c/d likewise; a/b × c/d = (a·c) / (b·d); a/b ÷ c/d = (a·d) / (b·c); the result is divided by gcd(numerator, denominator) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/fraction-arithmetic with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/math/fraction-arithmetic.md Input parameters: - `fraction_a` (string, required): First operand: a fraction '3/4', a mixed number '1 1/2' or '-1 1/2', a whole number '5' or a decimal '0.75'. - `fraction_b` (string, required): Second operand in the same formats. - `operation` (string): Operation applied as fraction_a (operation) fraction_b. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_circle_properties` (~293 tokens) Circle Calculator Use this when you know a circle's radius or diameter and need its area, circumference or the other dimension. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the shape is an ellipse (use ellipse), a solid ball (use sphere) or a disc with thickness (use cylinder). What it computes: Computes the area, circumference, diameter and radius of a circle from either its radius or its diameter. Lengths are unit-agnostic: the area is in the square of the input unit. Inputs: radius (number, units, optional); diameter (number, units, optional). Outputs: radius [units], diameter [units], circumference [units], area [units²]. Formula: r = radius (or diameter / 2); diameter = 2·r; circumference = 2·π·r; area = π·r² Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/circle with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/geometry/circle.md Input parameters: - `diameter` (number): Diameter of the circle (2 × radius). Used when radius is not given. Unit: units. - `radius` (number): Radius of the circle. Give either radius or diameter. Unit: units. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_descriptive_statistics` (~457 tokens) Descriptive Statistics Calculator Use this when you have a set of numeric observations and need its central tendency, spread or quartiles, e.g. the standard deviation of a data set. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need a single percentile or the percentile rank of one value (use percentile), a standardised score (use z-score), or statistics of two paired variables (use correlation or linear-regression). What it computes: Computes summary statistics for a list of numbers: count, sum, mean, median, mode, range, sample and population variance and standard deviation, standard error, coefficient of variation, quartiles (linear interpolation) and skewness. Inputs: values (number_list). Outputs: count, sum, mean, median, mode, mode_count, min, max, range, sample_variance, sample_std_dev, population_variance, population_std_dev, standard_error, coefficient_of_variation_percent [%], q1, q3, iqr, skewness. Formula: mean = Σx / n; sample_variance = Σ(x − mean)² / (n − 1); population_variance = Σ(x − mean)² / n; standard_error = s / √n; CV% = 100·s / mean; quartile at p: rank = p·(n − 1), value = x(⌊rank⌋) + (rank − ⌊rank⌋)·(x(⌊rank⌋+1) − x(⌊rank⌋)) on sorted data; skewness G1 = n / ((n − 1)(n − 2)) · Σ((x − mean) / s)³ Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/descriptive-statistics with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/statistics/descriptive-statistics.md Input parameters: - `values` (array, required): The data set, as a list of numbers (comma-separated or JSON array). At least 2 values are needed for sample statistics. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_t_test` (~789 tokens) T-Test Calculator Use this when you want to test whether a sample mean differs from a hypothesised value, whether two independent groups have different means, or whether paired before/after measurements changed. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the data are proportions or counts (use proportion-z-test or chi-square-test), you have three or more groups (ANOVA), or you already have t and df and only need the p-value (use p-value). What it computes: Runs a one-sample, Welch two-sample (unequal variances) or paired Student t-test from raw samples or summary statistics (mean, SD, n), returning t, degrees of freedom, two- and one-sided p-values, the confidence interval and the decision at the chosen alpha. Inputs: mode (enum, optional); sample_a (number_list, optional); sample_b (number_list, optional); mean_a (number, optional); sd_a (number, optional); n_a (integer, optional); mean_b (number, optional); sd_b (number, optional); n_b (integer, optional); hypothesized_mean (number, optional); alpha (number, optional). Outputs: test, mean_a, mean_b, mean_difference, standard_error, t_statistic, degrees_of_freedom, p_value_two_sided, p_value_one_sided, t_critical, ci_lower, ci_upper, significant, decision. Formula: one_sample: t = (x̄ − μ0) / (s / √n), df = n − 1. paired: same on the differences d = a − b. two_sample (Welch): t = (x̄a − x̄b − μ0) / √(sa²/na + sb²/nb), df = (sa²/na + sb²/nb)² / ((sa²/na)²/(na − 1) + (sb²/nb)²/(nb − 1)). p = P(|T_df| ≥ |t|); CI = estimate ± t(1 − alpha/2, df) × SE Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/t-test with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/statistics/t-test.md Input parameters: - `alpha` (number): Significance level as a probability (0.05 = 5 %), not a percentage. Confidence intervals and critical values use level 1 − alpha. - `hypothesized_mean` (number): Null-hypothesis value: the population mean (one_sample) or the mean difference (two_sample, paired). Usually 0 for differences. - `mean_a` (number): Summary alternative to sample_a: sample mean of A (in paired mode: mean of the differences a − b). - `mean_b` (number): Summary alternative to sample_b (two_sample only): sample mean of B. - `mode` (string): Which t-test to run. - `n_a` (integer): Number of observations in A, or number of pairs. - `n_b` (integer): Number of observations in B. - `sample_a` (array): Raw observations of the first (or only) sample. Alternatively give mean_a, sd_a and n_a. - `sample_b` (array): Raw observations of the second sample (two_sample) or the paired partner values in the same order (paired). Alternatively give mean_b, sd_b and n_b. - `sd_a` (number): Sample standard deviation (n − 1) of A, or of the paired differences. - `sd_b` (number): Sample standard deviation (n − 1) of B. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `convert_temperature` (~377 tokens) Temperature Converter Use this when you need a weather, cooking, body or laboratory temperature in another scale, e.g. Fahrenheit to Celsius or Celsius to Kelvin. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need to convert a temperature difference (a change of 10 °C is 18 °F, not 50 °F: multiply by 9/5 without the offset) or heat energy (use energy). What it computes: Converts temperatures between Celsius, Fahrenheit, Kelvin and Rankine with the exact defining relations (°F = °C × 9/5 + 32, K = °C + 273.15, °R = °F + 459.67) and rejects values below absolute zero. Inputs: value (number); from_unit (enum); to_unit (enum). Outputs: result, result_text, formula, factor, conversion_table. Formula: °F = °C × 9/5 + 32; °C = (°F − 32) × 5/9; K = °C + 273.15; °R = °F + 459.67 = K × 9/5 Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/temperature with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/conversion/temperature.md Input parameters: - `from_unit` (string, required): Unit of the input value. Accepted symbols: C, F, K, R; spelled-out names and common abbreviations are accepted too. - `to_unit` (string, required): Unit to convert into (same symbols as from_unit). - `value` (number, required): Amount to convert, expressed in from_unit. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_kinetic_energy` (~391 tokens) Kinetic Energy Calculator Use this when you need the energy of motion of an object of known mass and speed (vehicle, projectile, ball), for example to compare impact or braking energies. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when rotation contributes significantly (rotational energy ½·I·ω² is not included), speeds approach the speed of light (relativistic formula needed), or you need energy from height (use potential-energy). What it computes: Computes the translational kinetic energy of a moving mass from KE = ½·m·v², reported in joules, kilojoules, kilowatt-hours and kilocalories. Inputs: mass_kg (number, kg); velocity_m_s (number, m/s). Outputs: kinetic_energy_j [J], kinetic_energy_kj [kJ], kinetic_energy_kwh [kWh], kinetic_energy_kcal [kcal], velocity_km_h [km/h]. Formula: KE = ½ × mass_kg × velocity_m_s²; kJ = J / 1000; kWh = J / 3,600,000; kcal = J / 4184 Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/kinetic-energy with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/physics/kinetic-energy.md Input parameters: - `mass_kg` (number, required): Mass of the moving object in kilograms. Unit: kg. - `velocity_m_s` (number, required): Speed in metres per second (km/h ÷ 3.6, mph × 0.44704). Limited to 10 % of the speed of light, below which the classical formula is accurate to within 1 %. Unit: m/s. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `solve_ohms_law` (~400 tokens) Ohm's Law Calculator Use this when you know two of voltage, current and resistance in a DC or purely resistive circuit and need the third and the power. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the load is reactive (inductors or capacitors require impedance, not resistance), you want energy cost over time (use electric-power), or you need the equivalent resistance of several resistors (use resistors-series-parallel). What it computes: Solves Ohm's law V = I·R for whichever of voltage, current or resistance is omitted and reports the electrical power dissipated (P = V·I). Inputs: voltage_v (number, V, optional); current_a (number, A, optional); resistance_ohm (number, Ω, optional). Outputs: solved_for, voltage_v [V], current_a [A], current_ma [mA], resistance_ohm [Ω], power_w [W]. Formula: V = I × R; I = V / R; R = V / I; P = V × I = I² × R = V² / R Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/ohms-law with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/physics/ohms-law.md Input parameters: - `current_a` (number): Current through the component in amperes (1 mA = 0.001 A). Omit to solve for it. Unit: A. - `resistance_ohm` (number): Resistance in ohms (1 kΩ = 1000 Ω). Omit to solve for it. Unit: Ω. - `voltage_v` (number): Potential difference across the component in volts. Omit to solve for it. Unit: V. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_molar_mass` (~351 tokens) Molar Mass Calculator Use this when you have a chemical formula and need its molar mass (molecular weight), the number of atoms of each element, or its elemental mass-percent composition. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you already know the molar mass and want to convert between grams and moles (use moles-mass) or need a solution concentration (use molarity). What it computes: Parses a chemical formula (including brackets, nested groups and hydrates) and sums IUPAC 2021 standard atomic weights to give the molar mass in g/mol, plus the atom count and mass-percent composition of each element. Inputs: formula (string). Outputs: molar_mass_g_mol [g/mol], molecular_mass_da [Da], atom_count, element_count, composition. Formula: molar_mass = Σ (atomic_weight_i × count_i); mass_fraction_percent_i = 100 × atomic_weight_i × count_i / molar_mass Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/molar-mass with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/chemistry/molar-mass.md Input parameters: - `formula` (string, required): Chemical formula with case-sensitive element symbols, integer subscripts, brackets and optional hydrate dot, e.g. C6H12O6, Ca(OH)2, Fe2(SO4)3, CuSO4·5H2O. A trailing charge (NH4+, SO4^2-) or state (a… Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_age` (~391 tokens) Age Calculator Use this when you need someone's exact age on a date, the total number of days lived, the weekday they were born on, or how many days remain until their next birthday. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need the difference between two arbitrary dates with a business-day count (use date-difference) or a countdown to an event (use days-until). What it computes: Computes the exact age on a given date as years, months and days by Gregorian calendar arithmetic, plus total days and weeks, the weekday of birth, and the date of and days until the next birthday. Inputs: birth_date (date); as_of_date (date, optional). Outputs: years, months, days, age_text, total_days [days], total_weeks [weeks], age_decimal_years [years], next_birthday_date, days_until_next_birthday [days], day_of_week_born. Formula: years, months, days = calendar difference birth_date → as_of_date (when the day-of-month is smaller, days are borrowed from the month before as_of_date); total_days = as_of_date − birth_date; total_weeks = total_days / 7; age_decimal_years = total_days / 365.2425; next_birthday = first (month, day) of birth on or after as_of_date Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/age with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/age.md Input parameters: - `as_of_date` (string): Date on which to evaluate the age; defaults to the current UTC date. - `birth_date` (string, required): Date of birth (ISO 8601, YYYY-MM-DD). Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_date_difference` (~417 tokens) Date Difference Calculator Use this when you need the number of days, weeks or working days between two dates, or a calendar-style 'x years y months z days' difference. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you want to add or subtract a number of days from a date (use add-days), or you need an age with the next birthday (use age). What it computes: Counts the days between two ISO dates and expresses the gap as weeks and days, as a calendar breakdown in years, months and days, and as business days (Monday–Friday, public holidays not excluded). Inputs: start_date (date); end_date (date); include_end_date (boolean, optional). Outputs: days [days], weeks [weeks], remaining_days [days], weeks_and_days, calendar_years, calendar_months, calendar_days, calendar_text, business_days [days]. Formula: days = end_date − start_date (+1 if include_end_date); weeks = floor(days / 7); remaining_days = days mod 7; business_days = number of Mon–Fri dates in [start_date, end_date) or [start_date, end_date] when inclusive; calendar breakdown = whole years, months, then days borrowed from the month before end_date Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/date-difference with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/date-difference.md Input parameters: - `end_date` (string, required): Second date (YYYY-MM-DD). If it is earlier than start_date the dates are swapped and a note is returned. - `include_end_date` (boolean): true counts both endpoints (adds one day to days, weeks/days and business_days), e.g. for inclusive rental or leave periods. - `start_date` (string, required): First date (ISO 8601, YYYY-MM-DD). Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_ab_test_significance` (~608 tokens) A/B Test Significance Calculator Use this when you have visitors and conversions for a control and a variant (A/B test, split test, email test) and need to know whether the difference is statistically significant. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the metric is a mean (revenue per user, time on page) rather than a conversion proportion, or there are more than two variants (use a chi-square or multiple-comparison procedure). What it computes: Tests whether a variant's conversion rate differs from the control's using the pooled two-proportion z-test, and reports both rates, absolute and relative lift, z-score, two-sided p-value, a confidence interval for the difference and the sample size needed per variant to detect the observed lift with 80 % power. Inputs: control_visitors (integer); control_conversions (integer); variant_visitors (integer); variant_conversions (integer); confidence_level_percent (number, %, optional). Outputs: control_rate_percent [%], variant_rate_percent [%], absolute_lift_percentage_points [pp], relative_lift_percent [%], standard_error_percentage_points [pp], z_score, p_value, significant, ci_lower_percentage_points [pp], ci_upper_percentage_points [pp], required_visitors_per_variant, verdict. Formula: p1 = x1/n1, p2 = x2/n2, p̄ = (x1 + x2)/(n1 + n2); z = (p2 − p1) / √(p̄(1 − p̄)(1/n1 + 1/n2)); p_value = 2·(1 − Φ(|z|)); CI = (p2 − p1) ± z_crit·√(p1(1 − p1)/n1 + p2(1 − p2)/n2); n per variant = (z_crit·√(2·p̄(1 − p̄)) + z_0.80·√(p1(1 − p1) + p2(1 − p2)))² / (p2 − p1)² Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/ab-test-significance with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/business/ab-test-significance.md Input parameters: - `confidence_level_percent` (number): Confidence level for the significance decision and interval (95 → α = 0.05, two-sided). Unit: %. - `control_conversions` (integer, required): Conversions in the control group. - `control_visitors` (integer, required): Number of users exposed to the control (A). - `variant_conversions` (integer, required): Conversions in the variant group. - `variant_visitors` (integer, required): Number of users exposed to the variant (B). Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_haversine_distance` (~501 tokens) Haversine Distance Calculator Use this when you need the straight-line distance between two GPS coordinates or cities, e.g. for flight distance, range checks or geofencing. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need road distance, or ellipsoidal accuracy better than about 0.5 % (use a geodesic method such as Vincenty or Karney on WGS-84); for bearings and compass points use compass-bearing. What it computes: Computes the great-circle (as-the-crow-flies) distance between two points on a spherical Earth with the haversine formula, in kilometres, miles and nautical miles, together with the initial bearing, compass direction and the midpoint of the route. Inputs: lat1 (number, °); lon1 (number, °); lat2 (number, °); lon2 (number, °). Outputs: distance_km [km], distance_miles [mi], distance_nautical_miles [nmi], central_angle_degrees [°], initial_bearing_degrees [°], compass_direction, midpoint_lat [°], midpoint_lon [°]. Formula: a = sin²(Δφ/2) + cos φ1 · cos φ2 · sin²(Δλ/2); c = 2 · atan2(√a, √(1−a)); d = R · c with R = 6371.0088 km; θ = atan2(sin Δλ · cos φ2, cos φ1 · sin φ2 − sin φ1 · cos φ2 · cos Δλ) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/haversine-distance with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/time/haversine-distance.md Input parameters: - `lat1` (number, required): Latitude of point 1 in decimal degrees (north positive, south negative). Unit: °. - `lat2` (number, required): Latitude of point 2 in decimal degrees (north positive, south negative). Unit: °. - `lon1` (number, required): Longitude of point 1 in decimal degrees (east positive, west negative). Unit: °. - `lon2` (number, required): Longitude of point 2 in decimal degrees (east positive, west negative). Unit: °. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `price_black_scholes_option` (~712 tokens) Black-Scholes Option Calculator Use this when you need a theoretical European option price or its sensitivities from a given volatility, or want to check put-call parity for quoted prices. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the option is American with early exercise value, the underlying pays discrete dividends, or you need implied volatility from a market price (solve numerically instead). Informational only; not financial advice. What it computes: Prices a European call and put with the Black-Scholes-Merton formula from spot, strike, time to expiry, risk-free rate, volatility and a continuous dividend yield, and reports d1, d2 and the Greeks (delta, gamma, vega, theta, rho). Inputs: spot_price (number); strike_price (number); time_years (number, years); risk_free_rate_percent (number, % per year); volatility_percent (number, % per year); dividend_yield_percent (number, % per year, optional). Outputs: call_price, put_price, d1, d2, delta_call, delta_put, gamma, vega_per_1pct, theta_call_per_day, theta_put_per_day, rho_call_per_1pct, rho_put_per_1pct, put_call_parity_check. Formula: d1 = [ln(S/K) + (r − q + σ²/2)·T] / (σ·√T); d2 = d1 − σ·√T; C = S·e^(−qT)·N(d1) − K·e^(−rT)·N(d2); P = K·e^(−rT)·N(−d2) − S·e^(−qT)·N(−d1); Δ_call = e^(−qT)·N(d1); Γ = e^(−qT)·φ(d1)/(S·σ·√T); vega = S·e^(−qT)·φ(d1)·√T; Θ_call = −S·e^(−qT)·φ(d1)·σ/(2√T) − r·K·e^(−rT)·N(d2) + q·S·e^(−qT)·N(d1); ρ_call = K·T·e^(−rT)·N(d2), with r, q, σ as decimals Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/black-scholes with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/investing/black-scholes.md Input parameters: - `dividend_yield_percent` (number): Continuous dividend yield of the underlying in percent (0 for a non-dividend stock). Unit: % per year. - `risk_free_rate_percent` (number, required): Continuously compounded annual risk-free interest rate in percent. Unit: % per year. - `spot_price` (number, required): Current price of the underlying asset. - `strike_price` (number, required): Exercise price of the option. - `time_years` (number, required): Time until expiration in years (e.g. 0.25 for 3 months). Unit: years. - `volatility_percent` (number, required): Annualized volatility of the underlying's returns in percent. Unit: % per year. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_subnet` (~415 tokens) IP Subnet Calculator Use this when you need to know which subnet an IPv4 address belongs to, the host range and count of a /prefix, or the mask equivalent of a prefix length. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the address is IPv6, you want to split a block into several subnets (VLSM planning), or you only need a number in binary or hex (use base-converter). What it computes: Computes the network and broadcast addresses, subnet and wildcard masks, first and last host, usable and total addresses, address class and RFC 1918 private status for an IPv4 address in CIDR notation or with a dotted subnet mask, using 32-bit unsigned arithmetic. Inputs: cidr (string). Outputs: ip_address, cidr_notation, network_address, broadcast_address, subnet_mask, wildcard_mask, prefix_length [bits], host_bits [bits], first_host, last_host, usable_hosts, total_addresses, ip_class, is_private, address_scope, binary_mask, binary_address, ip_integer. Formula: mask = 2^32 − 2^(32 − prefix); network = ip AND mask; broadcast = network OR NOT mask; total = 2^(32 − prefix); usable = total − 2 (prefix ≤ 30), 2 (prefix 31), 1 (prefix 32) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/subnet-calculator with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/developer/subnet-calculator.md Input parameters: - `cidr` (string, required): IPv4 address followed by /prefix (0–32) or by a dotted subnet mask separated by a space or slash, e.g. 192.168.1.10/26 or 192.168.1.10 255.255.255.192. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `estimate_ev_charging_time` (~725 tokens) EV Charging Time Calculator Use this when you want to know how long an EV needs on a home wallbox, a public AC post or a DC fast charger to reach a target charge, or what the session costs at a given electricity price. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need a battery's charge time from ampere-hours and charger current (use battery-charge-time) or the driving range the added energy gives (use ev-range-efficiency); DC fast charging above about 80 % tapers strongly and takes longer than this constant-power estimate. What it computes: Estimates how long an electric vehicle takes to charge between two states of charge from its battery capacity, the charger power (capped by the onboard charger for AC charging) and the charging efficiency, plus the energy drawn from the grid and its cost. Inputs: battery_capacity_kwh (number, kWh); start_percent (number, %, optional); target_percent (number, %, optional); charger_power_kw (number, kW); max_onboard_charger_kw (number, kW, optional); charging_efficiency_percent (number, %, optional); electricity_price_per_kwh (number, per kWh, optional). Outputs: energy_added_kwh [kWh], energy_from_grid_kwh [kWh], effective_power_kw [kW], charging_time_hours [h], charging_time_text, cost, range_note. Formula: energy_added_kwh = battery_capacity_kwh × (target_percent − start_percent) / 100; energy_from_grid_kwh = energy_added_kwh / (charging_efficiency_percent / 100); effective_power_kw = min(charger_power_kw, max_onboard_charger_kw); charging_time_hours = energy_from_grid_kwh / effective_power_kw; cost = energy_from_grid_kwh × electricity_price_per_kwh Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/ev-charging-time with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/energy/ev-charging-time.md Input parameters: - `battery_capacity_kwh` (number, required): Usable battery capacity in kilowatt-hours (e.g. 40, 60, 75, 100). Unit: kWh. - `charger_power_kw` (number, required): Power the charging point delivers: 1.4–2.3 kW household socket (Level 1), 7–22 kW wallbox / AC post (Level 2), 50–350 kW DC fast charger. Unit: kW. - `charging_efficiency_percent` (number): Share of grid energy stored in the battery; 85–92 % is typical for AC charging (onboard charger and battery losses). Unit: %. - `electricity_price_per_kwh` (number): Optional price per kWh in your currency for the cost of the session (grid energy × price). Unit: per kWh. - `max_onboard_charger_kw` (number): Optional maximum AC charging power of the car's onboard charger (commonly 7.4 or 11 kW); the effective power is the lower of the two. Omit for DC charging. Unit: kW. - `start_percent` (number): State of charge at the start of the session. Unit: %. - `target_percent` (number): State of charge to reach; must be higher than start_percent. Unit: %. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_depth_of_field` (~579 tokens) Depth of Field Calculator Use this when you need to know how much of a scene is acceptably sharp for given camera settings, or how far sharpness extends in front of and behind the focused subject. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only need the focus distance that maximises depth of field (use hyperfocal-distance), or you shoot macro above about 0.2× magnification where lens extension and pupil magnification make the thin-lens equations inaccurate. What it computes: Computes the near and far limits of acceptable sharpness, the total depth of field and the hyperfocal distance from focal length, f-number, focus distance and the sensor's circle of confusion, using the standard thin-lens depth-of-field equations. Inputs: focal_length_mm (number, mm); aperture_f (number); focus_distance_m (number, m); sensor (enum, optional); coc_mm (number, mm, optional). Outputs: hyperfocal_m [m], near_limit_m [m], far_limit_m [m], far_limit_text, total_dof_m [m], in_front_of_subject_m [m], behind_subject_m [m], coc_used_mm [mm]. Formula: H = f² / (N·c) + f; near = s·(H − f) / (H + s − 2f); far = s·(H − f) / (H − s) when s < H, otherwise infinity (f = focal_length_mm, N = aperture_f, c = coc_mm, s = focus_distance_m × 1000, all in mm) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/depth-of-field with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/photography/depth-of-field.md Input parameters: - `aperture_f` (number, required): Lens f-number, e.g. 2.8 for f/2.8. - `coc_mm` (number): Optional acceptable circle-of-confusion diameter; overrides the preset value (full frame 0.030, APS-C 0.020, Micro Four Thirds 0.015, 1-inch 0.011 mm). Unit: mm. - `focal_length_mm` (number, required): Actual (not equivalent) focal length of the lens in millimetres. Unit: mm. - `focus_distance_m` (number, required): Distance from the camera's sensor plane to the focused subject in metres. Unit: m. - `sensor` (string): Sensor format; selects the circle of confusion (0.030 mm full frame, 0.020 mm APS-C, 0.015 mm Micro Four Thirds ...). Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `convert_betting_odds` (~471 tokens) Odds Converter Use this when you have odds in one format and need the other two, the implied probability of a price, or the payout of a stake at those odds. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need the combined price of several selections (use parlay-odds), the value of a bet given your own probability estimate (use bet-expected-value), or a bookmaker's margin across a whole market (use arbitrage-bet). Mathematics only; not gambling advice. What it computes: Converts betting odds between American (moneyline), decimal (European) and fractional (UK) formats, auto-detecting the input format, and reports the implied probability, profit and total return for a stake. Inputs: odds (string); format (enum, optional); stake (number, optional). Outputs: american, decimal, fractional, implied_probability_percent [%], profit_on_stake, total_return, detected_format. Formula: decimal = 1 + american/100 (american > 0) or 1 + 100/|american| (american < 0); decimal = 1 + a/b (fractional a/b); american = +100·(decimal − 1) if decimal ≥ 2, else −100/(decimal − 1); fractional = (decimal − 1) reduced with the GCD; implied_probability_percent = 100/decimal; total_return = stake × decimal Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/odds-converter with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/gaming/odds-converter.md Input parameters: - `format` (string): Format of the odds input. Auto: a/b or a-b with digits on both sides is fractional, a sign or an integer of 100 or more is American, anything else is decimal. - `odds` (string, required): Odds in any format: American +150 or -200, decimal 2.50, fractional 3/2 or 3-2, or evens. - `stake` (number): Stake used for the profit and return outputs (any currency). Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `find_chinese_zodiac` (~543 tokens) Chinese Zodiac Calculator (生肖) Use this when you need someone's Chinese zodiac sign and element from a Gregorian birth date, especially for January–February births where the boundary matters, or the sign's traditional compatibility groups. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need a full Bazi chart with month, day and hour pillars (use bazi-four-pillars), or the Western star sign (use zodiac). What it computes: Finds the Chinese zodiac animal (生肖 shengxiao), sexagenary year (干支 ganzhi), stem element, yin/yang, nayin (纳音) and fixed element for a birth date, using either the Chinese New Year boundary or the 立春 (Lichun) boundary, plus the traditional relationship groups (六合, 三合, 六冲, 六害, 相刑) and 本命年 years. Inputs: birth_date (date); boundary (enum, optional); reference_year (integer, optional). Outputs: zodiac, zodiac_cn, year_ganzhi, year_ganzhi_pinyin, year_english, stem_element, yin_yang, nayin, animal_fixed_element, year_used, chinese_new_year_date, lichun_datetime, boundary_note, benmingnian_years, secret_friend, trine_partners, clash, harm, punishment, age_in_reference_year [years], is_benmingnian_in_reference_year, reference_year_zodiac. Formula: year_used = Gregorian year, minus 1 when birth_date is before Chinese New Year (or before 立春 with boundary = lichun); ganzhi index = (year_used − 4) mod 60; animal = branch = index mod 12; 六合 partner = (13 − b) mod 12; 三合 = b ± 4; 六冲 = b + 6; 六害 partner = (7 − b) mod 12 Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/chinese-zodiac with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/lunar/chinese-zodiac.md Input parameters: - `birth_date` (string, required): Gregorian birth date (civil date in China Standard Time), 1900–2100. - `boundary` (string): Which event starts the zodiac year: Chinese New Year (popular usage, default) or 立春 around 4 February (astrological usage). - `reference_year` (integer): Optional Gregorian year for which to report the age and whether it is a 本命年. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `calculate_bazi_four_pillars` (~915 tokens) Bazi Four Pillars (八字) Use this when you need the four stem-branch pillars (年柱 月柱 日柱 时柱) of a birth moment, the day master and its ten-god relations, element balance, or the start age and sequence of the 大运 luck pillars. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only need the lunar date or zodiac of a date (use lunar-calendar-converter or chinese-zodiac), the stem-branch of a single date without an hour (use sexagenary-cycle), or an interpretation of the chart — this tool computes the traditional chart only and gives no predictions. What it computes: Builds the Bazi (八字, Bāzì) / Four Pillars (四柱) chart of a birth date and time: year pillar by 立春 (Lìchūn), month pillar by the 节 (jié) solar terms, day pillar from the sexagenary day count, hour pillar by the 五鼠遁 (Wǔshǔdùn) rule, plus day master, five-element counts, ten gods (十神), hidden stems (藏干), 纳音 (nàyīn), void branches (空亡) and the ten-year luck pillars (大运). Inputs: birth_date (date); birth_time (string); sex (enum); utc_offset_hours (number, h, optional); longitude_degrees (number, °, optional); late_zi_next_day (boolean, optional); include_hidden_stems (boolean, optional). Outputs: bazi_chart, year_pillar, month_pillar, day_pillar, hour_pillar, pillars_pinyin, pillars_english, day_master, zodiac, five_element_counts, missing_elements, dominant_element, ten_gods, hidden_stems, nayin, void_branches, luck_direction, luck_start_age, luck_start_age_years [years], luck_pillars, lunar_birth_date, solar_term_context, time_used, notes. Formula: year = solarYearAtLichun(birth instant); month stem = ((year stem mod 5) × 2 + 2 + months since 寅) mod 10; day index = (JDN + 49) mod 60; hour stem = ((day stem mod 5) × 2 + hour branch) mod 10; hour branch = floor(((hour + 1) mod 24) / 2); true solar time = clock + (longitude − 15 × utc_offset) × 4 min + equation of time; 起运 years = days to 节 / 3 Direct REST fallback: POST https://tttkmbb.com/ap… Input parameters: - `birth_date` (string, required): Gregorian civil date of birth in the local clock time of the birthplace (1900–2100). - `birth_time` (string, required): Local clock time of birth, 24-hour HH:MM. 23:00–00:59 is 子时 (Zǐ hour). - `include_hidden_stems` (boolean): Add the hidden stems (藏干) of the four branches to the element count with weights 1.0 (main), 0.5 (middle) and 0.3 (residual). - `late_zi_next_day` (boolean): true: 23:00–23:59 belongs to the next day's 子时 and the day pillar advances at 23:00. false: 晚子时 convention — the day pillar stays, only the hour stem is taken from the next day. - `longitude_degrees` (number): Optional east-positive longitude. When given, the clock time is converted to true solar time: correction = (longitude − 15 × utc_offset_hours) × 4 min + equation of time. Unit: °. - `sex` (string, required): Sex, used only for the direction of the luck pillars (阳年男/阴年女 forward, 阴年男/阳年女 backward). - `utc_offset_hours` (number): Time-zone offset of birth_time in hours (China Standard Time = 8; use the historical zone in force at birth). Unit: h. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `lookup_iching_hexagram` (~702 tokens) I Ching Hexagram Lookup (六十四卦) Use this when you need to identify or describe a hexagram, convert between its number, name, trigram pair and line pattern, or find its derived hexagrams and palace position. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you have moving lines and need the changed hexagram and reading rule (use hexagram-change), or you need to cast a hexagram from a date or numbers (use meihua-yishu). What it computes: Identifies one of the 64 hexagrams (六十四卦, liushisi gua) from its King Wen number, name, two trigrams or line digits and returns its lines, trigrams, nuclear (互卦, hugua), inverse (综卦, zonggua) and opposite (错卦, cuogua) hexagrams, its Jing Fang palace (京房八宫, Jingfang bagong) with 世/应 (shi/ying) lines, and the received judgment text (卦辞, guaci). Inputs: king_wen_number (integer, optional); name (string, optional); upper_trigram (string, optional); lower_trigram (string, optional); lines (string, optional). Outputs: number, name_cn, full_name_cn, pinyin, english, symbol, lines, lines_text, upper_trigram, lower_trigram, nuclear_hexagram, inverse_hexagram, opposite_hexagram, palace, palace_position, shi_line, ying_line, judgment_text, sequence_pair, binary_value, notes. Formula: lower trigram = lines 1–3, upper trigram = lines 4–6; nuclear = lines 2,3,4 + 3,4,5; inverse = reversed line order; opposite = each line flipped; binary_value = Σ line_i · 2^(i−1); 应 = 世 ± 3 Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/hexagram-lookup with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/yijing/hexagram-lookup.md Input parameters: - `king_wen_number` (integer): Hexagram number 1–64 in the King Wen sequence (1 = 乾, 64 = 未济). Give exactly one of king_wen_number, name, lines or the trigram pair. - `lines` (string): Six digits from line 1 (bottom) to line 6 (top): 1/0 for yang/yin, or 6/7/8/9 (老阴/少阳/少阴/老阳) as produced by yarrow or coin casting. - `lower_trigram` (string): Lower (inner) trigram, in any form accepted by bagua. - `name` (string): Chinese name (屯, 水雷屯, 乾为天; traditional forms accepted), pinyin (zhun; ambiguous pinyin such as qian or bi is rejected with the candidates) or Wilhelm/Baynes title (Difficulty at the Beginning). - `upper_trigram` (string): Upper (outer) trigram, in any form accepted by bagua (坎, kan, water, ☵, 010). Must be given together with lower_trigram. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ### `cast_plum_blossom_hexagram` (~875 tokens) Plum Blossom Numerology (梅花易数) Use this when you need a Plum Blossom hexagram cast for a moment or from numbers, with the upper/lower trigram arithmetic, the moving line and the 体/用 five-element reading laid out step by step. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you already have six lines from coins or yarrow (use liuyao for a 六爻 chart or hexagram-change for plain line changes), or you only want a hexagram's text and structure (use hexagram-lookup). What it computes: Casts an I Ching hexagram by the Plum Blossom (Meihua Yishu) method of Shao Yong from the lunar year, month, day and hour (年月日时起卦) or from two or three given numbers, then derives the moving line, changed hexagram (之卦), nuclear hexagram (互卦), the 体 (Ti, self) and 用 (Yong, matter) trigrams and their five-element relations. Inputs: method (enum, optional); date (date, optional); time (string, optional); number_1 (integer, optional); number_2 (integer, optional); number_3 (integer, optional); add_hour_to_moving_line (boolean, optional). Outputs: method_used, lunar_date, upper_trigram, lower_trigram, original_hexagram, original_lines, moving_line, moving_line_name, changed_hexagram, nuclear_hexagram, ti_trigram, yong_trigram, ti_element, yong_element, yong_ti_relation, nuclear_relations, changed_relation, ti_seasonal_strength, calculation_trace, reading_hint, disclaimer. Formula: Time method: year = branch number of the lunar year (子 = 1 … 亥 = 12), month = lunar month, day = lunar day, hour = 时辰 number (子 = 1 … 亥 = 12); upper = (year + month + day) mod 8, lower = (year + month + day + hour) mod 8, moving line = (year + month + day + hour) mod 6 (remainder 0 → 8 or 6); trigram numbers in earlier-heaven order 乾1 兑2 离3 震4 巽5 坎6 艮7 坤8. Two numbers: upper = number_1 mod 8, lower = number_2 mod 8, moving = (number_1 + number_2 [+ hour]) mod 6. Three numbers: moving = number_3 mod 6. 体 = trigram without the moving line, 用 = trigram with i… Input parameters: - `add_hour_to_moving_line` (boolean): Two-number method only: some schools add the 时辰 number (子 = 1 … 亥 = 12) of the given time before taking mod 6. - `date` (string): Civil date in China Standard Time (UTC+8), 1900–2100; defaults to today. - `method` (string): How the trigrams and the moving line are derived. - `number_1` (integer): First number for the number methods; mod 8 gives the upper trigram (0 counts as 8). - `number_2` (integer): Second number for the number methods; mod 8 gives the lower trigram. - `number_3` (integer): Third number for the three-number method; mod 6 gives the moving line (0 counts as 6). - `time` (string): Clock time HH:MM (China Standard Time) that fixes the 时辰 (double hour) for the time method or the optional hour addition. Output parameters: - `freshness` (object) - `links` (object) - `next_actions` (array) - `request` (object) - `result` (object) - `sources` (array) - `success` (boolean) - `timestamp` (string) - `version` (string) ## Diagnostics Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/com-tttkmbb-calcgrid/tttkmbb#diagnostics ## Score history - 2026-09-26: 74 - 2026-09-25: 74 ## Common questions ### What is the Calcgrid MCP server? Calcgrid is an MCP server listed in the public MCP registry as com.tttkmbb/calcgrid. Pinned IANA time-zone and finance calculators plus source-traceable China working-day data. This page covers its hosted endpoint (https://tttkmbb.com/mcp). ### Is the Calcgrid MCP server safe to use? Calcgrid scores 74 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm. ### What tools does the Calcgrid MCP server expose? Calcgrid exposes 50 tools: search_calculators, list_calculators, list_calculator_categories, get_calculator_schema, run_calculator, and 45 more. Their descriptions and schemas cost roughly 22,138 tokens of context every time the server is loaded. ### Does the Calcgrid MCP server require authentication? No. We connected to Calcgrid without credentials and it answered, so anything it exposes is reachable by anyone who knows the address. ### Is the Calcgrid MCP server still maintained? Calcgrid is still listed as active in the MCP registry. We last reached this channel on 26 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced. ## Links - Remote endpoint: https://tttkmbb.com/mcp - Website: https://tttkmbb.com/ - Changelog RSS feed: https://verifymcp.io/servers/com-tttkmbb-calcgrid/tttkmbb.xml - Changelog JSON feed: https://verifymcp.io/servers/com-tttkmbb-calcgrid/tttkmbb.json - HTML version of this page: https://verifymcp.io/servers/com-tttkmbb-calcgrid/tttkmbb