CronSpell
REMOTE · CRONSPELL.MIKE-TUSA.WORKERS.DEV
Validate and explain cron expressions; list next/previous run times in any time zone, DST-aware.
Available components
Last scanned (2 hours ago)
Scores higher than 58% of remote servers
Reachable. Last reached 5 Nov 2026.
Category Developer Tools
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. How we score → Why this is hard to score →
Endpoint Security63
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one. See how to fix → View diagnostics → Partial
- HTTPS enforcement could not be verified: the plaintext port answered with HTTP 405, which proves neither a plaintext path nor enforcement. View diagnostics → Unverified
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability67
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 1057 tokens (~264/item across 4 items; 4 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management47
- Stability observed for 14 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
- Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a current MCP spec version (2026-07-28).Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 5 Nov 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 43 to 47. That category is still filling its 30-day observation window: 13 days of observed history at the previous scan, 14 at this one. The score rises as the window fills, whether or not the server changes.
- 3 Nov 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 37 to 40. That category is still filling its 30-day observation window: 11 days of observed history at the previous scan, 12 at this one. The score rises as the window fills, whether or not the server changes.
- 1 Nov 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 30 to 33. That category is still filling its 30-day observation window: 9 days of observed history at the previous scan, 10 at this one. The score rises as the window fills, whether or not the server changes.
- 30 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.
- 27 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 13 to 17. That category is still filling its 30-day observation window: 4 days of observed history at the previous scan, 5 at this one. The score rises as the window fills, whether or not the server changes.
- 25 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.
- 23 Oct 26 +1
- Stability: unverified → 0.03 ▲ functional
- 22 Oct 26 65
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 5 Nov 2026 · Probed https://cronspell.mike-tusa.workers.dev/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=mike-tusa.workers.dev | CN=WE1,O=Google Trust Services,C=US | 12 Oct 2026 | 10 Jan 2027 | ECDSA 256 | ECDSA-SHA256 | f05aa95d8943eeed0e4e86dd1f6f1e02 |
| SANs: mike-tusa.workers.dev, *.mike-tusa.workers.dev | ||||||
| CN=WE1,O=Google Trust Services,C=US (CA) | CN=GTS Root R4,O=Google Trust Services LLC,C=US | 13 Dec 2023 | 20 Feb 2029 | ECDSA 256 | ECDSA-SHA384 | 7ff31977972c224a76155d13b6d685e3 |
| CN=GTS Root R4,O=Google Trust Services LLC,C=US (CA) | CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE | 15 Nov 2023 | 28 Jan 2028 | ECDSA 384 | SHA256-RSA | 7fe530bf331343bedd821610493d8a1b |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of cronspell.mike-tusa.workers.dev. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| dev. | present | 60074 | 8 | Verified |
| workers.dev. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| x-content-type-options | nosniff |
| x-frame-options | DENY |
| referrer-policy | no-referrer |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://cronspell.mike-tusa.workers.dev/mcp | Verified | 200 | |
| http (plaintext) | http://cronspell.mike-tusa.workers.dev/mcp | Inconclusive | 405 |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
cron_runs_between List cron runs between two times ~282
List every run of a cron expression between start and end (both inclusive) in an IANA time zone, DST-aware, oldest first. Default limit 20, max 100; truncated is true when there are more. Read-only. Same engine as GET /api/between.
| Name | Type | Req | Description |
|---|---|---|---|
| end | string | yes | Window end (inclusive). ISO 8601 with Z or an offset (2026-11-01T09:00:00Z), a local time read in the time zone (2026-11-01T09:00), or unix seconds. |
| expression | string | yes | Cron expression, e.g. "0 9 * * 1-5", "*/15 * * * *", "0 30 8 * * *" (6 fields = leading seconds) or "@daily". |
| limit | integer | – | Max runs to return (1-100). |
| start | string | yes | Window start (inclusive). ISO 8601 with Z or an offset (2026-11-01T09:00:00Z), a local time read in the time zone (2026-11-01T09:00), or unix seconds. |
| timezone | string | – | IANA time zone the schedule runs in, e.g. "America/Denver", "Europe/London". Default UTC. |
| Name | Type | Req | Description |
|---|---|---|---|
| complete | boolean | – | – |
| description | string | – | – |
| end | string | – | – |
| expression | string | yes | – |
| normalized | string | – | – |
| notes | array | yes | – |
| runs | array | yes | – |
| start | string | – | – |
| timezone | string | yes | – |
| truncated | boolean | yes | – |
| version | string | yes | – |
No examples provided.
explain_cron Explain a cron expression ~142
Explain a cron expression in plain English, e.g. "0 9 * * 1-5" → "At 09:00, on Monday through Friday." Also returns notes on cron rules that often surprise people (day-of-month OR day-of-week, seconds field, shorthand expansion). Invalid expressions return isError with the reason. Read-only. Same engine as GET /api/explain.
| Name | Type | Req | Description |
|---|---|---|---|
| expression | string | yes | Cron expression, e.g. "0 9 * * 1-5", "*/15 * * * *", "0 30 8 * * *" (6 fields = leading seconds) or "@daily". |
| Name | Type | Req | Description |
|---|---|---|---|
| dayMatching | string | – | – |
| description | string | yes | – |
| expression | string | yes | – |
| format | string | – | – |
| normalized | string | – | – |
| notes | array | – | – |
| version | string | yes | – |
No examples provided.
next_cron_runs List next (or previous) cron run times ~276
List the next (or, with direction "previous", the most recent past) run times of a cron expression in an IANA time zone, DST-aware. Each run has the local time with its UTC offset, the UTC time, unix seconds and weekday. Default 5 runs, max 20; searches up to 50 years. Read-only. Same engine as GET /api/next and GET /api/previous.
| Name | Type | Req | Description |
|---|---|---|---|
| count | integer | – | How many runs (1-20). |
| direction | string | – | "next" (default) or "previous" (most recent first). |
| expression | string | yes | Cron expression, e.g. "0 9 * * 1-5", "*/15 * * * *", "0 30 8 * * *" (6 fields = leading seconds) or "@daily". |
| from | string | – | Start point (exclusive); default now. ISO 8601 with Z or an offset (2026-11-01T09:00:00Z), a local time read in the time zone (2026-11-01T09:00), or unix seconds. |
| timezone | string | – | IANA time zone the schedule runs in, e.g. "America/Denver", "Europe/London". Default UTC. |
| Name | Type | Req | Description |
|---|---|---|---|
| complete | boolean | yes | – |
| description | string | – | – |
| direction | string | – | – |
| expression | string | yes | – |
| from | string | – | – |
| normalized | string | – | – |
| notes | array | yes | – |
| runs | array | yes | – |
| timezone | string | yes | – |
| version | string | yes | – |
No examples provided.
validate_cron Validate a cron expression ~145
Check whether a cron expression is valid. Returns valid true with the expanded values of every field (minute, hour, day of month, month, day of week, and seconds for 6-field expressions), or valid false with an error code, the field at fault and a message. Detects schedules that can never run (e.g. February 30). Read-only. Same engine as GET /api/validate.
| Name | Type | Req | Description |
|---|---|---|---|
| expression | string | yes | Cron expression, e.g. "0 9 * * 1-5", "*/15 * * * *", "0 30 8 * * *" (6 fields = leading seconds) or "@daily". |
| Name | Type | Req | Description |
|---|---|---|---|
| dayMatching | string | – | – |
| description | string | – | – |
| error | object | – | – |
| expression | string | yes | – |
| fields | object | – | – |
| format | string | – | – |
| normalized | string | – | – |
| valid | boolean | yes | – |
| version | string | yes | – |
No examples provided.
How do I install the CronSpell MCP server?
CronSpell is a hosted endpoint at https://cronspell.mike-tusa.workers.dev/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.
remote · cronspell.mike-tusa.workers.dev
claude mcp add --transport http dev-workers-mike-tusa-cronspell-cronspell 'https://cronspell.mike-tusa.workers.dev/mcp'
What is the CronSpell MCP server?
CronSpell is an MCP server listed in the public MCP registry as dev.workers.mike-tusa.cronspell/cronspell. Validate and explain cron expressions; list next/previous run times in any time zone, DST-aware. This page covers its hosted endpoint (https://cronspell.mike-tusa.workers.dev/mcp).
Is the CronSpell MCP server safe to use?
CronSpell scores 72 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 CronSpell MCP server expose?
CronSpell exposes 4 tools: validate_cron, explain_cron, next_cron_runs, cron_runs_between. Their descriptions and schemas cost roughly 845 tokens of context every time the server is loaded.
Does the CronSpell MCP server require authentication?
No. We connected to CronSpell without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the CronSpell MCP server still maintained?
CronSpell is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.