# Card log

> Every card log endpoint, generated from the API's own schemas.

Base URL `https://pidgeon.ai/api/v1`. Every request carries `Authorization: Bearer pgn_live_…`. The machine-readable version of this page is https://pidgeon.ai/openapi.json.

## GET /log/head

Read the card log’s signed head

Public, with no key. The card log holds every agent card Pidgeon has issued, changed or revoked, in an append-only Merkle tree (RFC 9162). `checkpoint` is its signed head, a C2SP checkpoint: check it against `verifier_key`, which never changes, and pin that. Cached for ten seconds. Limited per IP.

**Responses**

- `200` The head.
- `400` The request is not valid. `error.field` names the input at fault when there is one.
- `401` No API key, or one that is not valid.
- `403` Refused. `error.code` says why: `forbidden` when this key may not do this or the account is on hold, `abuse_blocked` when a limit says no.
- `404` No such resource, or one this key cannot reach. The two answer the same, so treat a 404 as “not available to you” rather than “does not exist”.
- `409` It conflicts with what is there: it already exists, or the `etag` you sent is not the current one.
- `429` Rate limited. `X-RateLimit-Reset` says when to retry.
- `500` Something went wrong on our side. Retry; if it keeps happening, tell us.
- `503` Something this needs is not answering right now. Retry in a moment.

## GET /log/checkpoint

Read the card log’s checkpoint as text

Public, with no key. The same signed checkpoint as `GET /log/head`, as `text/plain`, for a witness or monitor built for C2SP tiled logs.

**Responses**

- `200` The checkpoint: a signed note.
- `400` The request is not valid. `error.field` names the input at fault when there is one.
- `401` No API key, or one that is not valid.
- `403` Refused. `error.code` says why: `forbidden` when this key may not do this or the account is on hold, `abuse_blocked` when a limit says no.
- `404` No such resource, or one this key cannot reach. The two answer the same, so treat a 404 as “not available to you” rather than “does not exist”.
- `409` It conflicts with what is there: it already exists, or the `etag` you sent is not the current one.
- `429` Rate limited. `X-RateLimit-Reset` says when to retry.
- `500` Something went wrong on our side. Retry; if it keeps happening, tell us.
- `503` Something this needs is not answering right now. Retry in a moment.

## GET /log/entries

List card log entries

Public, with no key. Entries from `start` up to `end`, at most 100. An entry is one card subject’s claims at the moment they changed: `issued`, `updated` or `revoked`. `data` is its exact bytes, canonical JSON; a leaf hash is SHA-256 of 0x00 and `data`. Entries never change.

**Parameters**

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `start` | number | no |  |
| `end` | number | no |  |

**Responses**

- `200` A page of entries.
- `400` The request is not valid. `error.field` names the input at fault when there is one.
- `401` No API key, or one that is not valid.
- `403` Refused. `error.code` says why: `forbidden` when this key may not do this or the account is on hold, `abuse_blocked` when a limit says no.
- `404` No such resource, or one this key cannot reach. The two answer the same, so treat a 404 as “not available to you” rather than “does not exist”.
- `409` It conflicts with what is there: it already exists, or the `etag` you sent is not the current one.
- `429` Rate limited. `X-RateLimit-Reset` says when to retry.
- `500` Something went wrong on our side. Retry; if it keeps happening, tell us.
- `503` Something this needs is not answering right now. Retry in a moment.

## GET /log/proof

Prove a card is in the card log

Public, with no key. The inclusion proof (RFC 9162 §2.1.3) for a card’s latest entry, by its `sub`, against the current head; or for an entry `index` against the head at `tree_size`. 404 when it is not in the log: a card appears within five minutes.

**Parameters**

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `sub` | uuid | no |  |
| `index` | number | no |  |
| `tree_size` | number | no |  |

**Responses**

- `200` The proof.
- `400` The request is not valid. `error.field` names the input at fault when there is one.
- `401` No API key, or one that is not valid.
- `403` Refused. `error.code` says why: `forbidden` when this key may not do this or the account is on hold, `abuse_blocked` when a limit says no.
- `404` No such resource, or one this key cannot reach. The two answer the same, so treat a 404 as “not available to you” rather than “does not exist”.
- `409` It conflicts with what is there: it already exists, or the `etag` you sent is not the current one.
- `429` Rate limited. `X-RateLimit-Reset` says when to retry.
- `500` Something went wrong on our side. Retry; if it keeps happening, tell us.
- `503` Something this needs is not answering right now. Retry in a moment.

## GET /log/consistency

Prove the card log only grew

Public, with no key. The consistency proof (RFC 9162 §2.1.4) that the tree of `first` entries is a prefix of the tree of `second`: what a monitor asks each time the head moves, so nothing it saw was rewritten.

**Parameters**

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `first` | number | yes |  |
| `second` | number | yes |  |

**Responses**

- `200` The proof.
- `400` The request is not valid. `error.field` names the input at fault when there is one.
- `401` No API key, or one that is not valid.
- `403` Refused. `error.code` says why: `forbidden` when this key may not do this or the account is on hold, `abuse_blocked` when a limit says no.
- `404` No such resource, or one this key cannot reach. The two answer the same, so treat a 404 as “not available to you” rather than “does not exist”.
- `409` It conflicts with what is there: it already exists, or the `etag` you sent is not the current one.
- `429` Rate limited. `X-RateLimit-Reset` says when to retry.
- `500` Something went wrong on our side. Retry; if it keeps happening, tell us.
- `503` Something this needs is not answering right now. Retry in a moment.

## GET /log/monitors

List card log monitors

The names and domains this account watches the card log for. An owner, or an admin key over every address.

**Responses**

- `200` The monitors.
- `400` The request is not valid. `error.field` names the input at fault when there is one.
- `401` No API key, or one that is not valid.
- `403` Refused. `error.code` says why: `forbidden` when this key may not do this or the account is on hold, `abuse_blocked` when a limit says no.
- `404` No such resource, or one this key cannot reach. The two answer the same, so treat a 404 as “not available to you” rather than “does not exist”.
- `409` It conflicts with what is there: it already exists, or the `etag` you sent is not the current one.
- `429` Rate limited. `X-RateLimit-Reset` says when to retry.
- `500` Something went wrong on our side. Retry; if it keeps happening, tell us.
- `503` Something this needs is not answering right now. Retry in a moment.

## POST /log/monitors

Watch the card log for a name

Every new card log entry whose address, `on_behalf_of` or operator domain claims `term` — look-alikes included, such as a Greek Μ in “Meta” — emits a `card_log.matched` event to the account’s webhooks and, unless `email` is false, emails its owners. It watches from now on. An owner, or an admin key over every address; 50 at most.

**Parameters**

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `Idempotency-Key` | string | no | Any string unique to this attempt, reused on its retries. A repeat with the same key and the same request returns the first answer with `Idempotent-Replay: true` and does nothing — no second email. The same key with a different request is a `409`. Kept for 24 hours; a failure is not kept, so a retry after one runs. |

**Body**

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `term` | string | yes | A name or a domain to watch for, such as `meta` or `acme.com`. Look-alikes match too. |
| `email` | boolean | no | Email the workspace’s owners on a match, beside the `card_log.matched` event. |

**Responses**

- `201` The monitor.
- `400` The request is not valid. `error.field` names the input at fault when there is one.
- `401` No API key, or one that is not valid.
- `403` Refused. `error.code` says why: `forbidden` when this key may not do this or the account is on hold, `abuse_blocked` when a limit says no.
- `404` No such resource, or one this key cannot reach. The two answer the same, so treat a 404 as “not available to you” rather than “does not exist”.
- `409` Nothing was done by this call. `error.code` says which: `idempotency_in_progress` when the first request with this `Idempotency-Key` has not answered yet (wait `Retry-After` seconds and send it again), `idempotency_mismatch` when the key was used with a different request (use a new key).
- `429` Rate limited. `X-RateLimit-Reset` says when to retry.
- `500` Something went wrong on our side. Retry; if it keeps happening, tell us.
- `503` Something this needs is not answering right now. Retry in a moment.
- `504` Test mode only: `Pidgeon-Test-Fail: drop` dropped the answer (`test_dropped`). The request was done; retry it with the same `Idempotency-Key` to get the first answer.

## DELETE /log/monitors/{id}

Stop watching

**Parameters**

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `id` | string | yes |  |
| `Idempotency-Key` | string | no | Any string unique to this attempt, reused on its retries. A repeat with the same key and the same request returns the first answer with `Idempotent-Replay: true` and does nothing — no second email. The same key with a different request is a `409`. Kept for 24 hours; a failure is not kept, so a retry after one runs. |

**Responses**

- `200` Deleted.
- `400` The request is not valid. `error.field` names the input at fault when there is one.
- `401` No API key, or one that is not valid.
- `403` Refused. `error.code` says why: `forbidden` when this key may not do this or the account is on hold, `abuse_blocked` when a limit says no.
- `404` No such resource, or one this key cannot reach. The two answer the same, so treat a 404 as “not available to you” rather than “does not exist”.
- `409` Nothing was done by this call. `error.code` says which: `idempotency_in_progress` when the first request with this `Idempotency-Key` has not answered yet (wait `Retry-After` seconds and send it again), `idempotency_mismatch` when the key was used with a different request (use a new key).
- `429` Rate limited. `X-RateLimit-Reset` says when to retry.
- `500` Something went wrong on our side. Retry; if it keeps happening, tell us.
- `503` Something this needs is not answering right now. Retry in a moment.
- `504` Test mode only: `Pidgeon-Test-Fail: drop` dropped the answer (`test_dropped`). The request was done; retry it with the same `Idempotency-Key` to get the first answer.