# Anchor Manifest specification (slim)

> Specification for the Anchor Manifest, a small JSON document at /.well-known/anchor.json that links a publisher's tools to the standards they already use (MCP server.json, OpenAPI, A2A agent cards, llms.txt, x402) and adds the things agents still can't find anywhere, namely read-only variants, payment terms, status, changelog and a way to verify who published it.

- Full: https://www.anchorterminal.com/docs/manifest.md (~2,150 tokens) · this version ~480 tokens · JSON https://www.anchorterminal.com/docs/manifest.json · canonical https://www.anchorterminal.com/docs/manifest
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-05

Serve `https://<publisher-domain>/.well-known/anchor.json` (JSON, CORS on). Optional `Link: </.well-known/anchor.json>; rel="anchor-manifest"` and a line in `llms.txt`. Draft v0.1, fields added not removed before v1.

## Shape

- `anchor` "0.1" · `publisher {name, url, contact, docs, llmsTxt}` · `tools[]` · `verify {dnsTxt, http}` · `updated` (ISO date).
- Tool entry: `id` (reverse-DNS, same as the MCP registry), `kind` (`mcp`, `http`, `openapi`, `a2a`, `sdk`), `name`, `description`, `endpoint`, `packages[{registry, name}]`, `transport` (`streamable-http`, `stdio`, `sse`), `auth[]` (`none`, `oauth2`, `api-key`, `pat`, `httpsig`, `x402`), `readOnlyVariant` (URL, scored), `scopedVariants{}`, `payments[{protocol, version, networks (CAIP-2), asset, priceUsd, unit, discovery}]`, `pricing` (URL), `freeTier {cardRequired, limit}`, `schemas {mcpServerJson, openapi, a2aAgentCard, jsonSchema}`, `status`, `changelog` (scored), `deprecations[{what, sunset, replacement}]`, `telemetry {collected, optOut, policy}`, `security`, `source`, `license`.

## Verification (any one)

DNS TXT at `_anchor.<domain>` with `anchor-verify=<token>` · served same-origin as the tool's `endpoint` · `id` is a verified MCP registry namespace whose `server.json` lists the same endpoint. Unverified manifests are ignored, never penalised.

## Effects

Fetched, verified and diffed on every crawl. Facts update the same day. Declared sunsets are graceful, never negative events. A declared `readOnlyVariant` is probed. Declared `payments` are probed like any x402 endpoint. Example document in the full page.