feat(server): ACP Captains propose a Crew without a native prompt

[bryantderosier]

Important

⚠️ Merge order: merge these in this exact order

This PR is part of the Captains stack. Merge top to bottom, one at a time; each PR is based on the one above it. The stack has no migrations and no ordering against the other Crews PRs.

1. refactor(server): one J5 tool pre-approval list for Codex and Claude #301: One J5 tool pre-approval list, and every adapter can be a Captain
2. feat(server): OpenCode Captains propose a Crew without a native prompt #302: OpenCode Captains propose a Crew without a native prompt
3. feat(server): Pi Captains propose a Crew without a native prompt #303: Pi Captains propose a Crew without a native prompt
4. feat(server): ACP Captains propose a Crew without a native prompt #304: ACP Captains propose a Crew without a native prompt ⬅️ this PR

Problem

ACP registry agents run on AcpAdapterV2, and a t3-code MCP call reached acpPermissionDisposition as an ordinary unclassified tool (#267). That meant a native card in interactive modes and a refusal for read-only personas, so a persona Captain couldn't propose and a persona seat couldn't message its Captain or write its handoff. codex-acp asks a second time through an mcp_tool_call_approval_<toolCallId> elicitation.

What I changed

• apps/server/src/j5/a2a/mcp/acpToolApproval.ts (new):
  • j5AcpT3ToolName proves which t3-code tool a call invokes, or returns nothing.
  • j5AcpPermissionResponse returns a one-time allow for a proven, pre-approved call.
  • j5AcpMcpElicitationDisposition handles codex-acp's elicitation, linked by request id.
• AcpAdapterV2.ts (upstream, FORK.md case 48): one prefix at each call site. The permission handler returns the J5 response when it's defined, before acpPermissionDisposition. The elicitation handler tries j5AcpMcpElicitationDisposition(...) ?? first. AcpClientPolicy.ts is untouched.
• docs/user/personas.md: the Codex, Qwen Code, and Claude Code agents from the ACP registry move to the harnesses that never add a step.

Why this shape

ACP has no typed MCP call, and nothing at permission time proves a call came from T3's server: the bridge only sees a call after it's approved. So identity can come only from structured fields the harness fills from its own MCP dispatch. I dropped title matching entirely because some harnesses let the model write titles (pi-acp puts the shell command there; cline and Kimi append raw arguments).

Invariants

• Identity comes only from the root session's recorded tool-call state for that toolCallId. The permission request must repeat the recorded kind and can only veto.
• Granting fields:
  • codex-acp: _meta.is_mcp_tool_call with rawInput.server/rawInput.tool;
  • qwen: _meta.serverId plus a _meta.toolName of mcp::t3-code::<tool> (both required);
  • claude-acp: _meta.claudeCode.toolName of mcp__t3-code__<tool>.
• Every identity field present, in the state or the request, must name t3-code and the same tool. An untagged rawInput server/tool still counts and vetoes on disagreement, as does goose's extension name.
• Edit, delete, and move never match; execute matches only under the codex-acp tag.
• Only an allow_once option is ever selected. With none offered, upstream's policy decides. The tool must be in j5PreapprovedTools for the thread's policy.
• Child sessions are ignored, since tool-call ids are only unique per session.

Surfaces

Surface	Decision
Entry points (chat, Settings, command palette, keybinding)	Unaffected.
Clients (web, desktop, mobile)	Unaffected.
Providers	ACP registry agents: codex-acp, qwen, and claude-acp match. Every other ACP agent, Grok and Antigravity included, keeps today's verdict and stays on the still-prompts list.
Contracts (packages/contracts)	Unchanged.
Reverse states	n/a.
Connection modes (local, remote, tunnel)	Unaffected.
Upstream files / FORK.md	AcpAdapterV2.ts, recorded as FORK.md case 48.
Docs	docs/user/personas.md.

Out of scope

• FORK.md numbering follows landing order: the formatter keeps the case list consecutive, so the Captains stack (feat(server): OpenCode Captains propose a Crew without a native prompt #302–feat(server): ACP Captains propose a Crew without a native prompt #304) and feat(crews): answer a Crew thread's provider approvals and questions from the Inbox #309 both start at case 46 on their branches. Whichever lands second renumbers its cases and file-table rows when it's brought up to date with j5/main.

• Capture and match Grok MCP permission requests #268 (Grok) and Match Antigravity MCP permission requests by server #269 (Antigravity): their payloads carry no server-identifying field in the fixtures we have, and the tests assert they don't match.

• droid, Gemini CLI, Amp, Kilo, opencode-acp, Copilot, Auggie, glm, and Kimi have no structured identity field, so they stay on the still-prompts list (Pre-approve J5 tools on ACP registry agents #267's final rule).

• Accepted risk: a harness running a user-configured server named exactly t3-code in place of T3's bridge would get that server's J5-named tools pre-approved. It's noted in the module doc comment.

Upgrade and data

None.

Verification

• acpToolApproval.test.ts: parity across the policy matrix plus the persona policy for each of the three forms, plus negatives:
  • a title-only call, with and without state;
  • full codex fields on the request with no state;
  • a request that contradicts the recorded tool, kind, or id;
  • an offer of only allow_always;
  • a foreign server in any field;
  • execute outside the codex tag, and edit/delete/move;
  • the acp-mcp-call fallback and bare names;
  • non-J5 t3-code tools;
  • Antigravity and Grok shapes;
  • a qwen serverId with a bare or unprefixed name.
• acpToolApproval.adapter.test.ts drives both hooks through AcpAdapterV2, including child-session reuse of a root call id.
• 552 tests pass across the mcp dir, provider/acp, and the ACP, OpenCode, and Pi adapters.

Review focus

• claimsOf in acpToolApproval.ts: this is the security boundary. I changed two things from the earlier draft. An untagged rawInput server/tool now vetoes; the draft ignored it, so a request naming another tool there was allowed, and its own adapter test caught that. And qwen now grants only through the full mcp::t3-code:: name.
• Whether any ACP harness reports an MCP call's kind as execute without the codex tag; those calls fall through to upstream's verdict.

Closes #267

Claude Opus 5.5 via Claude Code

🤖 Generated with Claude Code

[coderabbitai]

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[Jacksondr5]

[Review panel: Opus 5.5 + Astra + Fable 5.1] FORK.md: apps/server/src/orchestration-v2/Adapters/AcpAdapterV2.ts has no file-table row.

Case 48 describes the edit, but the upstream-file table has no entry for AcpAdapterV2.ts. #302 and #303 both add rows for their upstream files (OpenCodeAdapterV2.ts → 46; PiAdapterV2.ts, PiAdapterV2.test.ts, piT3McpExtensionSource.ts → 47). Without a row, an upstream advance that walks the table won't see the two J5 call-site prefixes in this file, and a rebase can silently drop them. The J5 handler would still exist, so nothing fails loudly.

Fix: add | apps/server/src/orchestration-v2/Adapters/AcpAdapterV2.ts | N | 48 | in sorted position.

[Jacksondr5]

[Review panel: Opus 5.5 + Astra + Fable 5.1] Live interaction tests, run by Astra on the stack tip (62d6dbd). No seats were launched: every roster was declined and every control was denied.

Harness	Scenario	Result
claude-acp 0.81.2	Supervised Captain propose_crew	PASS: roster only, no native card (screenshot)
claude-acp 0.81.2	Native Write control	PASS: native prompt still shown
codex-acp 1.13.1	Captain propose_crew, with codex-acp's own mode set to "Ask for approval"	PASS: roster only, no native card (screenshot)
codex-acp 1.13.1	Negative control	PASS
Native Codex / Claude	Interactive and never rosters (#301 has no behavior change)	PASS
Native Codex	Supervised preview_open	PASS: prompts
Native Claude	Supervised preview_open	Runs without a prompt. This predates the stack: upstream's non-read-only mcp__t3-code__* wildcard.

Protocol observations that matter for the claimsOf rework:

• claude-acp: the initial tool_call carries _meta.claudeCode.toolName = mcp__t3-code__propose_crew, kind other, and rawInput: {}. It arrived 369 ms before request_permission, which repeats the kind and meta and offers allow_once.
• codex-acp: the initial tool_call carries kind execute, _meta.is_mcp_tool_call: true, and rawInput.server/tool = t3-code/propose_crew. It arrived 2 ms before a sparse request_permission that carries only toolCallId, kind, and status. Identity therefore has to come from the recorded state. If the update lands late, the call falls back to a native prompt, which fails safe.
• codex-acp 1.13.1: its default mode is its own "Approve for me", even under T3 Supervised. It never emitted the mcp_tool_call_approval_ elicitation, so j5AcpMcpElicitationDisposition has no live coverage.
• Antigravity: not configured, so the bypass above has unit and source proof only.

[Jacksondr5]

Closing (Jackson, 2026-09-26). Per the ruling on #233, J5 pre-approves its tools only on Codex and Claude. Other harnesses may show their own MCP prompt once before the roster card, which is acceptable. ACP's permission request carries no trustworthy server identity, so any version has to infer identity per agent. That's hard, it's security-sensitive (see the panel's Antigravity finding), and it's upstream adapter territory. A general fix for T3's own MCP tools belongs upstream and is tracked in #276. Thanks for the careful work here: the review surfaced real upstream gaps, which are now recorded.

[Jacksondr5]

Reopened: closing it was my overreach, not Jackson's call. The decision above stands (per #233, J5 won't pre-approve its tools on this harness), so it won't merge. @bryantderosier, closing it is yours to do whenever you like.

[bryantderosier]

@Jacksondr5 Closing this per your ruling on #233: J5 pre-approves its tools only on Codex and Claude, and a ACP Captain may show its own MCP prompt once before the roster card. The general fix for T3's own MCP tools is tracked upstream in #276. Thanks for the panel's review; the gaps it found are recorded there. I'm closing #267 as not planned for the same reason.