Add agent-approval-check composite action (#1429)

* Add agent-approval-check composite action

Require N human approvals on PRs that contain agent-authored commits.
Posts an agent-approval-check commit status that repos mark as a
required check on protected branches.

This is a sanitized port of the check Anthropic runs internally on
every agent-authored PR — same detection rules, /approve <sha>
comment flow, sibling-PR-same-SHA guard, and fail-closed semantics,
with the Anthropic-specific path exemptions and kill-switch removed
and config moved to action inputs.

Co-Authored-By: Claude <noreply@anthropic.com>

* Drop stray internal acronym from comment

* agent-approval-check: require write-access approvers, pin deps, pagination + doc fixes

🏠 Remote-Dev: homespace

* agent-approval-check: prettier

🏠 Remote-Dev: homespace

* agent-approval-check: verify approver write permission via REST; commits(last:100); docstring

🏠 Remote-Dev: homespace

* agent-approval-check: use headRefOid; drop pull_request_review trigger and correct threat-model docs

🏠 Remote-Dev: homespace

* agent-approval-check: stale-notification wording, no-retry-on-4xx, docstring API-call count

🏠 Remote-Dev: homespace

* agent-approval-check: fail-closed sibling guard on commits-ordering edge; drop stale 'reviewed' from README

🏠 Remote-Dev: homespace

* agent-approval-check: drop hardcoded API-call counts from logs; clarify author write-access requirement in README

🏠 Remote-Dev: homespace

* agent-approval-check: count all agent-email commits (close-reopen bypass); validate REQUIRED_APPROVALS>=1; exempt_head_branches warning

🏠 Remote-Dev: homespace

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Octavian Guzu <oct@anthropic.com>

agent-approval-check/action.yml

@@ -0,0 +1,72 @@
+name: Agent Approval Check
+description: |
+  Require N human approvals on PRs that contain agent-authored commits
+  (Claude, Claude Code, or any configured bot identity). Posts an
+  `agent-approval-check` commit status — mark it as a required check on
+  protected branches to gate merges.
+
+inputs:
+  github_token:
+    description: Token with statuses:write and pull-requests:write on this repo.
+    default: ${{ github.token }}
+  required_approvals:
+    description: Number of distinct human approvals required. Must be >= 1.
+    default: "2"
+  agent_emails:
+    description: Comma-separated committer emails treated as agent-authored.
+    default: noreply@anthropic.com
+  agent_logins:
+    description: |
+      Comma-separated GitHub logins treated as agents — a PR opened by, or an
+      APPROVED review from, one of these triggers the check.
+    default: claude[bot],claude-code[bot]
+  excluded_approvers:
+    description: Comma-separated logins whose approvals never count (e.g. rubber-stamp bots).
+    default: ""
+  exempt_head_branches:
+    description: |
+      Comma-separated glob patterns; PRs from matching head branches auto-pass.
+      WARNING: leave empty — branch names are attacker-controlled, so this is
+      not a safe place to encode trust.
+    default: ""
+  exempt_path_prefixes:
+    description: Comma-separated path prefixes; PRs touching only these auto-pass.
+    default: ""
+  protected_bases:
+    description: |
+      Comma-separated base branches this check gates. Empty = the repo's
+      default branch only. PRs targeting any other base are refused (no
+      status posted) so a sibling PR sharing the head SHA can't get the
+      shared commit stamped green.
+    default: ""
+  config_file:
+    description: Optional path to an agent-identities YAML file (overrides the inline inputs).
+    default: ""
+  docs_url:
+    description: Link shown in the PR comment footer.
+    default: "https://github.com/anthropics/claude-code-action/tree/main/agent-approval-check"
+
+runs:
+  using: composite
+  steps:
+    - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
+      with:
+        python-version: "3.12"
+    - run: pip install 'httpx==0.28.1' 'pyyaml==6.0.3' 'tenacity==9.1.4'
+      shell: bash
+    - run: python "${{ github.action_path }}/agent_approval_check.py"
+      shell: bash
+      env:
+        GH_TOKEN: ${{ inputs.github_token }}
+        GH_REPOSITORY: ${{ github.repository }}
+        GH_EVENT_NAME: ${{ github.event_name }}
+        GH_EVENT_PATH: ${{ github.event_path }}
+        REQUIRED_APPROVALS: ${{ inputs.required_approvals }}
+        AGENT_EMAILS: ${{ inputs.agent_emails }}
+        AGENT_LOGINS: ${{ inputs.agent_logins }}
+        EXCLUDED_APPROVERS: ${{ inputs.excluded_approvers }}
+        EXEMPT_HEAD_BRANCHES: ${{ inputs.exempt_head_branches }}
+        EXEMPT_PATH_PREFIXES: ${{ inputs.exempt_path_prefixes }}
+        PROTECTED_BASES: ${{ inputs.protected_bases }}
+        CONFIG_FILE: ${{ inputs.config_file }}
+        DOCS_URL: ${{ inputs.docs_url }}