generated: '2026-08-30'
method: probed
source: >-
  live probes of https://sourcebook.acus.gov/api.php and
  https://sourcebook.acus.gov/rest.php/v1/* on 2026-08-30 (response bodies and headers),
  cross-read against the MediaWiki 1.43 Action API help served at
  https://sourcebook.acus.gov/api.php
provider: Administrative Conference of the United States
providerId: administrative-conference-of-the-united-states
description: >-
  Cross-cutting runtime semantics for the one callable ACUS API surface, the MediaWiki
  Action API and REST API v1 behind the Federal Administrative Procedure Sourcebook at
  sourcebook.acus.gov. Everything below was observed on the wire; nothing is inferred
  from a vendor claim, because ACUS publishes no API documentation of its own — the
  contract is whatever MediaWiki 1.43.0 exposes.
surfaces:
  - name: MediaWiki Action API
    base: https://sourcebook.acus.gov/api.php
    style: RPC-over-querystring (action= parameter)
    actions_available: 54
    formats: [json, jsonfm, none, php, phpfm, rawfm, xml, xmlfm]
    self_documenting: https://sourcebook.acus.gov/api.php
  - name: MediaWiki REST API v1
    base: https://sourcebook.acus.gov/rest.php/v1
    style: resource-oriented REST
    verified_paths:
      - /page/{title}
      - /page/{title}/bare
      - /page/{title}/html
      - /revision/{id}/bare
      - /search/page?q=&limit=
      - /search/title?q=&limit=
auth_style:
  read: anonymous, no credential of any kind
  write: MediaWiki session cookie plus a CSRF token from action=query&meta=tokens
  oauth: not installed (action=rsd reports OAuth false)
  see: authentication/administrative-conference-of-the-united-states-authentication.yml
versioning:
  scheme: path-versioned on REST (/rest.php/v1/), unversioned on the Action API
  current_version: MediaWiki 1.43.0 (siprop=general generator field)
  deprecation_signalling: >-
    None published by ACUS. Upstream MediaWiki emits deprecation warnings in the
    Action API `warnings` envelope; no Deprecation or Sunset (RFC 8594) response
    headers were observed on any probed response.
pagination:
  action_api:
    style: continuation token
    request_params: ['continue', 'limit', '{prefix}limit', '{prefix}continue']
    response_field: continue
    note: >-
      The Action API returns a top-level `continue` object whose members are fed back
      verbatim as query parameters on the next request. `batchcomplete` marks the end
      of a batch.
  rest_api:
    style: bounded result set
    request_params: [limit]
    response_field: pages
    note: >-
      /search/page and /search/title accept `limit` and return a `pages` array. No cursor
      or offset field was returned on the probed responses.
field_selection:
  action_api: >-
    `prop`, `list`, `meta` and `siprop` select which projections are returned; `*props`
    parameters narrow fields per submodule. This is genuine sparse-fieldset control.
  rest_api: >-
    Representation is chosen by path suffix, not a query parameter — /bare returns the
    metadata envelope, no suffix returns metadata plus wikitext `source`, /html returns
    Parsoid HTML.
error_envelope:
  rest_api:
    content_type: application/json
    shape:
      errorKey: machine-readable error slug, e.g. rest-no-match
      messageTranslations: object of BCP-47 language code to human message
      httpCode: integer, mirrors the HTTP status
      httpReason: HTTP reason phrase
    rfc9457: false
    note: >-
      Structured and machine-readable but NOT application/problem+json — no type, title,
      detail or instance members. See errors/administrative-conference-of-the-united-states-problem-types.yml.
  action_api:
    content_type: application/json
    shape:
      errors: array of {code, module, "*"} when formatversion=2 / errorformat is set
      warnings: array, used for deprecation and parameter warnings
      servedby: request node identifier
    note: >-
      The Action API answers HTTP 200 for most application-level errors and reports the
      failure inside the body. An agent MUST parse the body, not the status code.
request_id_tracing:
  header: x-request-id
  observed: true
  example: apQH1-iZEGwdCsKBP0ackAAAAIE
  note: >-
    Present on both the Action API and REST responses. Useful for a support report, but
    ACUS publishes no support channel that accepts it.
rate_limit_signalling:
  headers_observed: []
  note: >-
    No X-RateLimit-*, no RateLimit-*, no Retry-After on any probed response. The only
    published throttling signal on any acus.gov host is `Crawl-delay: 2` in robots.txt.
    See rate-limits/administrative-conference-of-the-united-states-rate-limits.yml.
caching:
  action_api: 'cache-control: private, must-revalidate, max-age=0; vary: Accept-Encoding,Treat-as-Untrusted,Cookie'
  rest_api: 'cache-control: max-age=5; etag and last-modified both present; vary: x-restbase-compat'
  conditional_requests: supported on REST (ETag / Last-Modified observed)
content_negotiation:
  action_api: format= query parameter (json is the practical default; jsonfm is the HTML debug view)
  rest_api: fixed per path suffix; application/json for metadata, text/html for /html
security_headers:
  x-content-type-options: nosniff
  x-frame-options: DENY (Action API)
  server: Apache/2.4.62 (Amazon Linux)
idempotency:
  supported: na
  reason: >-
    The publicly reachable surface is read-only. Every anonymously callable operation is a
    GET and is therefore naturally idempotent. No idempotency key header is offered, and
    none is needed, because there is no anonymous write path. NOT scored as a miss — scored
    as not-applicable.
dry_run_mode:
  supported: na
  reason: No anonymous write surface to rehearse.
reversibility:
  applicable: false
  grade: na
  reason: >-
    Read-only for every consumer who can actually authenticate. All 54 Action API modules
    are advertised, but the write half (edit, upload, move, delete, protect, revisiondelete,
    rollback, undelete, userrights, block) requires a Sourcebook wiki account and the wiki
    offers no public registration, so no agent or third-party integrator has a write path
    that could need reversing.
  write_surfaces: []
  note: >-
    For completeness: MediaWiki itself carries strong native reversal semantics for
    account holders — action=undelete restores deleted pages, action=rollback reverts the
    last contributor's consecutive edits, and revision history makes every edit
    reversible without a stated time window. ACUS publishes no policy stating a retention
    or restoration window, so no window is asserted here.
agent_notes:
  - >-
    A default HTTP client cannot reach this API. curl, python-requests and GPTBot all
    receive HTTP 403 from every acus.gov host; only a browser User-Agent returns 200.
    Any agent integration must set a browser-like User-Agent, which is at odds with
    MediaWiki's own convention of sending a descriptive bot UA.
  - >-
    The corpus is small and stable: 30 pages, 21 content articles, 1,998 edits, 0 files
    (siprop=statistics, 2026-08-30). A full harvest is a handful of requests, so polling
    should be rare and conditional requests (ETag) should be used.
cross_references:
  errors: errors/administrative-conference-of-the-united-states-problem-types.yml
  authentication: authentication/administrative-conference-of-the-united-states-authentication.yml
  lifecycle: lifecycle/administrative-conference-of-the-united-states-lifecycle.yml
  rate_limits: rate-limits/administrative-conference-of-the-united-states-rate-limits.yml
  conformance: conformance/administrative-conference-of-the-united-states-conformance.yml
maintainers:
  - FN: Kin Lane
    X-twitter: apievangelist
    email: info@apievangelist.com