5a8e3a14ee
The proposal survives contact with the code with three amendments, per the RFCs-are-proposals rule. (1) A mode transition logs a request/header-delta only when expressible: adding exit_plan_mode resorts the canonical tool list, and a pure reordering has no delta form, so entering plan mode logs the full fallback snapshot — the attributability claim holds either way. (2) The proposed/ skeleton converts to the implemented grammar: Proposal → Decision, the roadmap's staging (now history) drops to the standing Deferred list, and Acceptance criteria + Risks fold into Consequences (what holds, then the accepted costs, including the ACP v2 mode-removal migration). (3) The two recorded scenarios stay pending a with-key session, recorded in Deferred. The docs tail completes: the cookbook's plan-mode row upgrades from sketch to the shipped package, architecture.md gains the ctx.modes capability row (ceiling 1640 → 1650: a new capability service's table row does not fit the old budget), and every reference repoints to implemented/.
plan-acp-agent
The coding agent as an ACP server with session modes composed — the live composition of the plan-mode RFC.
What it demonstrates
session/new advertises the mode picker (default / plan); the editor's session/set_mode switches the session, applied at the next turn boundary. In plan mode the model sees only the read-only allowlist (read, todo_write, exit_plan_mode here — this tree loads no web tools) plus the plan-mode guidance section, and every call outside the allowlist is denied at tools/pre-execute with a reason that steers it back to planning. The model leaves by presenting its plan through exit_plan_mode: the plan markdown renders as the tool's call card, the review question arrives as an elicitation form (approve / keep planning, free text welcome), and a keep-planning answer returns the feedback to the model verbatim.
Run
pnpm run demo:plan-acp # needs DEEPSEEK_API_KEY (repo-root .env works)
Drive it from Zed or any ACP client; the mode picker appears on the session. Switching back to default (or an approved exit_plan_mode) restores the full toolset on the next step.
Tests
pnpm run test:snapshot replays the keyless modes-advertise scenario: the modes advertisement on session/new, both session/set_mode round-trips with their optimistic current_mode_update, and the loud rejection of an unknown mode id, as committed wire bytes. The recorded plan-mode arc (explore → denied write → exit_plan_mode → scripted approve / keep-planning) awaits a with-key recording session; its deny/review texts are pinned at the unit tier meanwhile (packages/mode/mode/tests, packages/ui/acp/tests/modes.spec.ts).