[teamleaderleo]

Re-cut of #23869 (by the cosmic-gray lane 01a15bdd, now gone), rebased onto feat-cmux-next. The stale-pr-reconciler gave it to hb-acpmux; Leo, 2026-10-25: "these should never have been this stale for this long". Credit for the work goes to #23869. It is split in two to stay under 800 lines: this PR is the daemon side (acpmux, cmux-tui), and #25440 is the pane side (Swift, web). Each lands on its own: until both are in, an answer relayed from the pane is still refused, the same as today.

Answering an agent's question in the Mac app's chat pane failed for a chat on an ssh peer (Leo hit it live on huge-blue). The peer's acpmux refused it with "approve this on the Mac app: allowing a permission is accepted only from the cmux app".

Cause

A chat on another machine gets its answers over a connection that is never the person, so the peer counts an allow only when it carries the person's decision proof (cx-0q7o). That proof never covered question answers: person_decided and respond_permission refused any proof when answers was present.

Fix

• acpmux: a new proof, acpmux-person-decision-answers-v1 (hub/person/decision_answers.rs), signs the allow's five parts plus the sha256 of the canonical answers JSON (approvers::answers_digest). When the answer has annotations (Claude Code's chosen preview and notes, Send a question's chosen preview back to Claude Code (annotations) #24356), the sha256 of the canonical annotations is a seventh part.
• An answer from a connection that is not the person counts only under that proof, so a relay can neither swap the answers nor add annotations. Annotations from such a connection count only on the proof path: never for an ancestor's answer, and never with a phone's signed answer, whose signature covers the answers alone. Each nonce is still spent once, under the prompt's lock.
• cmux-tui agent-session-permission carries answers and annotations (objects of at most 64 KiB each, annotations only beside answers) to acpmux unchanged (spec/commands.md).

Tests

• cargo test -p acpmux --test person_allow:
  • a_relayed_answer_counts_with_the_persons_proof_over_exactly_its_answers, red at 2f32042 (a compile error: the proof does not exist yet).
  • a_relayed_answers_annotations_count_only_under_the_persons_proof_over_them, red at 9aab5bf (run: the annotated answer is refused).
  • the_answers_decision_proof_matches_the_apps_vector, with annotations and a character outside the BMP. The vectors were computed independently in Python, and the Swift side checks the same vectors in agent pane: a question answered in the pane for a chat on another machine carries the person's proof (re-cut of #23869, pane side) #25440.
  • All 25 green at b7ab635 (run).
• cargo test -p cmux-tui-core:
  • a_question_answer_carries_its_answers_and_proof_to_acpmux_unchanged, red at e621126.
  • a_question_answers_annotations_go_to_acpmux_unchanged, red at 9aab5bf.
  • Green at b7ab635.
• cargo test -p acpmux --test hub_integration questions: 8 of 8 pass. clippy -D warnings is clean, and rustfmt is clean at this head.
• agent_tools::tests::own_servers_run_under_the_daemon_prefix also fails on base 41e4d6b (run). It is not this PR's.

Review

Codex gpt-6-astra xhigh, through the bare mirror. Round 1 BLOCKed with two findings: the ticket did not bind the answers, and the remote wire dropped annotations. Both are fixed with tests. Round 2 BLOCKed on Unicode equality in the Swift ticket, which is fixed in #25440. Round 2 confirmed the daemon side by inspection. The final verdict at this head is in a comment.

No new timers or observers.

No capture: the change is in the proof and the daemon verb, and nothing in the UI changes.

Changelog

Fixed: Answering an agent's question in a chat on another machine no longer fails with "accepted only from the cmux app" (with #25440).

risk:high: this changes what the person's decision proof covers (auth).

Agent session: big-red
🤖 Generated with Claude Code

[teamleaderleo]

Owned by hb-acpmux on big-red · session

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[github-actions]

cmux status _{(one comment, edited in place; each line is updated by the job that owns it)}

Review fd848fb: HQ feed card · gallery before/after runs · checks

App of this head (app.zip, kept 1 day)

gh workflow run reload-build.yml -R manaflow-ai/cmux --ref feat-cmux-next -f tag=pr25424 -f ref=lane/hb-stale-pane-answer-proof -f platform=macos -f backend_mode=local

Stale: these images are of b7ab635; the head is now a7c004b and a new capture is running.

Gallery before/after for b7ab635: 16 states rendered, 4 images differ, 1951 more touched states not rendered. Images are in the run's artifact, not on this public PR.

gh run download 40306404424 -R manaflow-ai/cmux -n gallery-advisory-25424-b7ab6351d6d05f7e241cbb7540362466c75ecc6d (then read gallery-review.json)

States

State	Theme	Status	Diff	Picked by
agent-pane.chat-width/standard	Apple System Colors	changed	23.4%	imports direct.ts (1 hops)
agent-pane.chat-width/standard	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.chat-width/wide	Apple System Colors Light	changed	1.53%	imports direct.ts (1 hops)
agent-pane.chat-width/wide	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.chat-width/wide-blocks	Apple System Colors Light	changed	1.53%	imports direct.ts (1 hops)
agent-pane.chat-width/wide-blocks	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.composer-floats/scrolled-to-end	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.composer-floats/scrolled-to-end	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.composer-floats/composer-grown	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.composer-floats/composer-grown	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/new-chat	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/new-chat	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/after-turn	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/after-turn	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/working	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/working	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/typing-in-dock	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/typing-in-dock	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/long-title	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.docked-chat/long-title	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.gutter-select/from-left-margin	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.gutter-select/from-left-margin	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.gutter-select/from-right-margin	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.gutter-select/from-right-margin	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.inspector/chat-menu	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.inspector/chat-menu	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.inspector/wire-log	Apple System Colors Light	changed	0.0135%	imports direct.ts (1 hops)
agent-pane.inspector/wire-log	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.orchestration-lab/local-queue	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.orchestration-lab/local-queue	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)
agent-pane.orchestration-lab/build-box	Apple System Colors Light	unchanged	0%	imports direct.ts (1 hops)
agent-pane.orchestration-lab/build-box	Apple System Colors	unchanged	0%	imports direct.ts (1 hops)

_{Pick other states with a Gallery: entry.id, entry.id/variant line in the PR body.}

[teamleaderleo]

Review (codex gpt-6-astra xhigh, hb-stale-pane-review): SHIP at 40cba81

[teamleaderleo]

cmux-next fast gates / post cmux-next/fast-gates is red on 16 of 20 fresh feat-cmux-next PR heads in the last 2:00:00, so it is most likely a base red, not this PR's. The base-reds lane has it; a base merge picks up the fix once it lands.

[github-actions]

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.4032307340502 (35e1c1f88b)
• cmux NEXT nightly 1.0.0-nightly.4032901198601 (079a929b63)