Check that what a message says is attached matches the attachments actually supplied

$0.005 USDC per call · Agent infrastructure · POST /api/v1/attachment-references · Id attachment-references

Compares a message's wording with its attachment list: 'see attached' with nothing attached, a named file (report.pdf) that is not in the list, a kind of file mentioned (the spreadsheet, a screenshot, the PDF) that no attachment matches by extension or MIME type, and a stated count ('two files') that differs from the list; attachments the text never mentions are listed. Mentions inside a negation ('no attachment', 'forgot to attach') are ignored. Rule-based and English only; it never opens a file or checks that a file's content matches its name. Offsets for every mention are in UTF-16, code points, UTF-8 bytes and graphemes.

What you get

Catches 'see attached' emails that go out with nothing attached. 20,000 characters per $0.005 call.

Call it

Send the JSON body below to https://agents.writerslogic.com/api/v1/attachment-references. 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/attachment-references \
  -H 'content-type: application/json' \
  -d '{"text":"Hi, please find attached the Q3 report (q3-report.pdf) and the budget spreadsheet.","attachments":[{"name":"q3-report.pdf","mimeType":"application/pdf"}]}'

Input

Field	Type	Required	Description
`text`	string; length 1..20000	yes	Message body.
`attachments`	array<object>; max 50 items	yes	The attachments actually present; may be empty.

Example request body

{
  "text": "Hi, please find attached the Q3 report (q3-report.pdf) and the budget spreadsheet.",
  "attachments": [
    {
      "name": "q3-report.pdf",
      "mimeType": "application/pdf"
    }
  ]
}

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.
`claims`	array<object>; max 50 items	no	Phrases asserting an attachment.
`namedFiles`	array<object>; max 50 items	no
`kindMentions`	array<object>; max 50 items	no
`count`	object	no
`unmentioned`	array<string>; max 50 items	no	Attachment names the text never refers to by name or kind.
`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 context-evidence-kit package.

Machine-readable

This agent as JSON (schemas, example, OpenAPI operation)
Free signed sample response
OpenAPI 3.1 · Catalog · Index of every agent