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Due Date

REMOTE · DUE-DATE.GUMBALLTOOLS.COM · SCANNED SEP 25

Estimate a due date from LMP, conception, or ultrasound, with ACOG redating rules.

+3 this week 73 Trust /100
Trust breakdown (7 categories)

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
Transport & Reachability100
Schema Quality & AI Usability60
  • AI-judged instruction clarity (excellent).Pass
  • Context-footprint check failed: tool/resource definitions use about 934 tokens (~934/item across 1 items; 1 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 Management67
  • Stability observed for 20 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
Tool Safety100
  • No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
  • We read all 1 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
  • An AI judge read all 1 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
Install

How do I install the Due Date MCP server?

Due Date is a hosted endpoint at https://due-date.gumballtools.com/api/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 · due-date.gumballtools.com

# add to Claude Code
claude mcp add --transport http com-gumballtools-due-date 'https://due-date.gumballtools.com/api/mcp'
// .cursor/mcp.json
{
  "mcpServers": {
    "com-gumballtools-due-date": {
      "url": "https://due-date.gumballtools.com/api/mcp"
    }
  }
}
// .vscode/mcp.json
{
  "servers": {
    "com-gumballtools-due-date": {
      "type": "http",
      "url": "https://due-date.gumballtools.com/api/mcp"
    }
  }
}
# ~/.codex/config.toml
[mcp_servers.com-gumballtools-due-date]
url = "https://due-date.gumballtools.com/api/mcp"
// opencode.json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-gumballtools-due-date": {
      "type": "remote",
      "url": "https://due-date.gumballtools.com/api/mcp",
      "enabled": true
    }
  }
}
# add to OpenClaw
openclaw mcp add com-gumballtools-due-date --url 'https://due-date.gumballtools.com/api/mcp' --transport streamable-http
# ~/.hermes/config.yaml
mcp_servers:
  com-gumballtools-due-date:
    url: "https://due-date.gumballtools.com/api/mcp"
// ~/.netclaw/config/netclaw.json
{
  "McpServers": {
    "com-gumballtools-due-date": {
      "Transport": "http",
      "Url": "https://due-date.gumballtools.com/api/mcp"
    }
  }
}
# add to Vellum
assistant mcp add com-gumballtools-due-date -t streamable-http -u 'https://due-date.gumballtools.com/api/mcp'
// mcp.json
{
  "mcpServers": {
    "com-gumballtools-due-date": {
      "type": "http",
      "url": "https://due-date.gumballtools.com/api/mcp"
    }
  }
}

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

Changelog

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.

  • 25 Sept 26 0
    • We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
  • 24 Sept 26 +1

    No change was recorded against any check on this day. Stability & Change Management went from 60 to 63. That category is still filling its 30-day observation window: 18 days of observed history at the previous scan, 19 at this one. The score rises as the window fills, whether or not the server changes.

  • 22 Sept 26 +1

    No change was recorded against any check on this day. Stability & Change Management went from 53 to 57. That category is still filling its 30-day observation window: 16 days of observed history at the previous scan, 17 at this one. The score rises as the window fills, whether or not the server changes.

  • 19 Sept 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.

  • 17 Sept 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.

  • 15 Sept 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.

  • 13 Sept 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.

  • 11 Sept 26 +1

    No change was recorded against any check on this day. Stability & Change Management went from 17 to 20. That category is still filling its 30-day observation window: 5 days of observed history at the previous scan, 6 at this one. The score rises as the window fills, whether or not the server changes.

Diagnostics

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 25 Sept 2026 · Probed https://due-date.gumballtools.com/api/mcp

TLS valid

Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .

Subject Issuer Valid from Valid until Key Signature Serial
CN=*.gumballtools.com CN=YR2,O=Let's Encrypt,C=US 6 Sept 2026 5 Dec 2026 RSA 2048 SHA256-RSA 60927985e79d22e7a1106139f609d74b0e4
SANs: *.gumballtools.com, gumballtools.com
CN=YR2,O=Let's Encrypt,C=US (CA) CN=Root YR,O=ISRG,C=US 3 Sept 2025 2 Sept 2028 RSA 2048 SHA256-RSA 4ebd24947e24d394802d84a52fd5b319
CN=Root YR,O=ISRG,C=US (CA) CN=ISRG Root X1,O=Internet Security Research Group,C=US 13 May 2026 2 Sept 2032 RSA 4096 SHA256-RSA f24b6d17f9d9ad7cb1c9fea78782699f

Background: What to check on a remote MCP endpoint →

DNSSEC insecure

Validation of due-date.gumballtools.com. — Not signed

Zone DS Keys Algorithms Outcome
. trust_anchor 20326, 38696 8, 8 Verified
com. present 19718 13 Verified
gumballtools.com. 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
strict-transport-security max-age=63072000

Background: How OAuth 2.1 works in the 2026 MCP spec →

Transports 2 probes
Transport URL Outcome Status Location
streamable-http https://due-date.gumballtools.com/api/mcp Verified 200
http (plaintext) http://due-date.gumballtools.com/api/mcp HTTPS enforced 308 https://due-date.gumballtools.com/api/mcp
MCP tools · 1 exposed · ~934 tokens

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 →

Tool Tokens
due_date ~934

Estimate a due date and gestational age from a last menstrual period, a known conception date, an IVF transfer date, or an ultrasound measurement. Use this for any pregnancy-dating question rather than doing the arithmetic. Three reasons, and they are all things models get wrong: 1. THE OFF-BY-TWO-WEEKS ERROR. Gestational age is counted from the first day of the LAST MENSTRUAL PERIOD, not from conception. At "6 weeks pregnant", conception was about 4 weeks ago. Weeks 1 and 2 precede conception entirely. This is restated wrongly constantly, and a two-week error in dating is a large error. 2. CYCLE LENGTH. Naegele's rule (LMP + 280 days) silently assumes a 28-day cycle with ovulation on day 14. For a 35-day cycle the unadjusted answer is a week out. This applies the adjustment; most calculators do not. 3. THE ACOG REDATING TABLE. Whether an ultrasound should REPLACE a period-based estimate depends on the discrepancy AND on how far along the scan was: more than 5 days up to 8w6d, 7 days to 15w6d, 10 days to 21w6d, 14 days to 27w6d, 21 days thereafter. Nobody recalls that table correctly from memory. Do not guess at it. Input: `method` is one of lmp | conception | ivf-day3 | ivf-day5 | ultrasound. `date` is the date that method is based on — the first day of the last period, the conception date, the transfer date, or the scan date — as YYYY-MM-DD. Free-form dates are REFUSED rather than guessed, because "03/04/2025" is two different dates a month apart depending on the reader. For `lmp`, pass `cycleLength` if it is known and is not 28. For `ultrasound`, pass `scanWeeks` and `scanDays` — the gestational age the scan reported — and pass `lmp` as well if it is known, which is what triggers the redating check. `asOf` sets the reference date for "how far along"; it defaults to today. Returns: the estimated due date, gestational age in clinical weeks-plus-days notation, the estimated conception date, days remaining, trimester, dated milestones including the anatomy-scan…

NameTypeReqDescription
asOfstring–YYYY-MM-DD reference date for "how far along", default today. Set it when the user is asking about a date other than now.
cycleLengthnumber–Cycle length in days, 20-45, default 28. Only affects `lmp`. Worth asking the user for: Naegele's rule assumes 28 days, and a 35-day cycle moves the estimate a week later.
datestringyesYYYY-MM-DD. The date the method is based on: the FIRST DAY of the last menstrual period, the conception date, the IVF transfer date, or the date of the scan. Free-form dates are REFUSED, not guessed.
lmpstring–For `ultrasound`: the last menstrual period, YYYY-MM-DD. Supplying it is what runs the ACOG Committee Opinion 700 redating check — without it the two estimates cannot be compared and the tool says so.
methodstringyesHow the pregnancy is being dated. Use `lmp` unless the user has given you a conception date, a transfer date, or a scan measurement — `lmp` is what people usually know.
scanDaysnumber–For `ultrasound`: the DAYS part, 0-6. Scan reports use a "12w3d" format.
scanWeeksnumber–For `ultrasound`: the WEEKS part of the gestational age the scan reported.

No output schema declared.

No examples provided.

Common questions

What is the Due Date MCP server?

Due Date is an MCP server listed in the public MCP registry as com.gumballtools/due-date. Estimate a due date from LMP, conception, or ultrasound, with ACOG redating rules. This page covers its hosted endpoint (https://due-date.gumballtools.com/api/mcp).

Is the Due Date MCP server safe to use?

Due Date scores 73 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 Due Date MCP server expose?

Due Date exposes 1 tool: due_date. Their descriptions and schemas cost roughly 934 tokens of context every time the server is loaded.

Does the Due Date MCP server require authentication?

No. We connected to Due Date without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

Is the Due Date MCP server still maintained?

Due Date is still listed as active in the MCP registry. We last reached this channel on 25 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.