Do licences, certificates or insurance policies cover a required period without gaps?

$0.005 USDC per call · Business, finance and compliance · POST /api/v1/credential-coverage · Id credential-coverage

Given a required date range (a contract term, a project, a shipment window) and up to 200 credentials each valid from a date to a date (both inclusive), reports the merged covered ranges, every uncovered gap with its first and last day and length, and whether each checkpoint date is covered; a credential ending the day before the next starts is contiguous. Built for an agent verifying insurance, licences, calibration or certification continuity. It does not verify that a credential is genuine, its scope, or renewal status, and does not read the clock.

What you get

A one-day lapse between renewals is invisible in a list and fatal in a claim.

Call it

Send the JSON body below to https://agents.writerslogic.com/api/v1/credential-coverage. An unpaid request answers 402 with the price and how to pay; a request that fails with a 5xx status is not charged.

curl -i -X POST https://agents.writerslogic.com/api/v1/credential-coverage \
  -H 'content-type: application/json' \
  -d '{"required":{"start":"2026-01-01","end":"2026-12-31"},"credentials":[{"id":"policy-1","validFrom":"2025-07-01","validTo":"2026-06-30"},{"id":"policy-2","validFrom":"2026-07-02","validTo":"2027-06-30"}],"checkpoints":["2026-07-01"]}'

Input

Field	Type	Required	Description
`required`	object	yes
`credentials`	array<object>; max 200 items	yes
`checkpoints`	array<string; length 0..10>; max 100 items	no	Specific dates that must be covered (delivery date, audit date).
`toleratedGapDays`	integer; 0..365	no	Gaps up to this many days are reported but do not fail (a grace period you are entitled to).

Example request body

{
  "required": {
    "start": "2026-01-01",
    "end": "2026-12-31"
  },
  "credentials": [
    {
      "id": "policy-1",
      "validFrom": "2025-07-01",
      "validTo": "2026-06-30"
    },
    {
      "id": "policy-2",
      "validFrom": "2026-07-02",
      "validTo": "2027-06-30"
    }
  ],
  "checkpoints": [
    "2026-07-01"
  ]
}

Result

The response is { "data": ..., "_provenance": ... }. data carries these fields; _provenance is a signed W3C Verifiable Credential with a C2PA-style manifest, checked free at POST /api/v1/verify-provenance.

Field	Type	Required	Description
`status`	string; one of "pass", "fail", "unknown", "unsupported"	no	pass: every rule held. fail: a rule was violated (see witnesses). unknown: the input lacks the evidence to decide. unsupported: outside what this engine covers. Missing evidence is never a pass.
`covered`	array<object>	no
`gaps`	array<object>	no
`checkpoints`	array<object>	no
`requiredDays`	integer	no
`coveredDays`	integer	no
`reason`	string	no
`witnesses`	array<object>	no
`versions`	object	no	Every semantic dependency of this answer (engine, tables and their as-of dates, tokenizer, calendar, rounding profile).
`limits`	array<string>	no
`deterministic`	boolean	no	Always true: pure code, no model.

Pay and connect

Available through: x402 (USDC on Base), MCP. MCP clients reach it through the calendar-deadline-kit package.

Machine-readable

This agent as JSON (schemas, example, OpenAPI operation)
Free signed sample response
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