---
title: "Archive Evidence Gap"
method: POST
path: "/archive/evidence-gap"
---

# Archive Evidence Gap

`POST /archive/evidence-gap`

## Request

- Base URL: `https://api.colourmemory.com` (the document declares no server; this is the origin it was published from)
- URL: `https://api.colourmemory.com/archive/evidence-gap`
- Auth: none declared

Given a hex value and a proposed claim about it, return whether the archive supports
that claim, what is missing, what kind of source would be needed, and safe wording.

This is Colour Memory's anti-hallucination endpoint. It turns the absence of evidence
into a forensic finding rather than a gap to be filled with invention.

A claim can only be "supported" or "partial" if a candidate is both a genuinely
close colour match (low dE2000) AND has real word-level overlap with the claim,
using whole-word matching against a stopword-filtered set. A nearby-but-different
colour that merely shares a generic word can never produce false confidence.

Example: hex #4A535C + proposed_claim 'cyanosis in a death chamber'
Returns: nearest archive support, whether the claim is supported, what is missing,
         what source type would be needed, and safe agent wording.

## Headers

- `x-api-key` string, nullable
- `origin` string, nullable

## Request body

- EvidenceGapRequest
  - `hex` string, required
  - `proposed_claim` string, required
  - `archive` string
  - `n_candidates` integer

## Response `200`

Successful Response

- unknown

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/colourmemory/apis/colour-memory-api.md) · [All operations](https://skmtc.dev/colourmemory/apis/colour-memory-api/llms.txt) · [OpenAPI document](https://skmtc.dev/colourmemory/apis/colour-memory-api/revisions/4ba028f64042?raw)