Harness: Claude Code (v3)

Read at launch with the contract and the charter.

Launch

The launch file’s first line is the command; the message follows it:

cmd: claude --model claude-opus-5-5 --effort medium
You are the root. Read $PROTOCOL_SOURCE/sources/loop/contract.md, $PROTOCOL_SOURCE/sources/loop/harness-claude.md
and <abs charter path> in full. Write <abs closeout path> last, then reconcile and reply (contract section 12).
Standing: <abs path> sha256=<hex>
<each charter authority: or live: line touching customer data or a live system, verbatim>

• The root runs Opus 5.5 at medium unless the charter’s root: says otherwise.
• The agent-workflows Stop hook arms on “You are the root” plus exactly one codex/closeout-<date>-loop<N>.md path, or a bare path to a launch file holding them. It lets the turn end only when that closeout counts (contract section 12, step 4) or the last line is a current PAUSED: or WAITING: ... until <UTC> line; otherwise it re-prompts up to three times in a chain.
• Nothing wakes an owner-only wait. Before ending that turn, start one background command that sleeps until its WAITING deadline, so the session wakes then (contract section 12).

Permissions and owner questions

• A lane cannot clear an auto-mode permission block the root could, so SSH, deploys, tenant or cloud mutations, secret-store writes and destructive git stay with the root. Running the charter’s gate route (a just gate recipe, even one that reaches a build host) is lane work, not SSH.
• The auto-mode classifier weighs only owner messages, never the charter file. The launch message therefore repeats each charter authority: and live: line that touches customer data or a live system, verbatim, after Standing:. Paste the message text, not a bare launch-file path, when it carries such lines.
• AskUserQuestion blocks the session: call it only as contract section 7 allows, never in overnight mode, and reconcile (section 12) as soon as it returns.

Routes

Role	subagent_type	Model / effort
implementation (default)	agent-workflows:worker	Sonnet 5.5 / high
judgement, unknown cause, seams, compose and board batches	agent-workflows:senior	Opus 5.5 / medium
escalation (tripwire or owner-named)	agent-workflows:senior-escalation	Opus 5.5 / xhigh
review and security review	agent-workflows:reviewer	Opus 5.5 / high
read-only mapping, sweeps, wave drafts, log reduction	agent-workflows:scout	Sonnet 5.5 / medium

• Pass no model to these agents: it overrides the pin. Give each dispatch a description of <lane> <task>.
• Every role keeps a one-hour prompt cache, so a lane can wait on a gate slot without rewriting its context.
• If an agent-workflows:* type is missing, the plugin is not installed: stop and say so in chat.

Dispatch and repairs

• Dispatch unnamed, in the background. Never subagent_type: "fork" for a lane.
• The agent-workflows PreToolUse hook denies an armed root’s Agent call unless the prompt’s first non-empty line is the brief header (contract section 3). Fix the header and dispatch again.
• At most 30 running subagents (CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS); the 31st fails with Concurrent subagent limit reached. Wait for a return instead of retrying. Keep about 7 free when lanes may delegate; a brief says whether a lane may.
• A lane’s completion arrives as a task notification. Repair rounds and answers go to the same lane with SendMessage to its agent id, carrying the new evidence.
• TaskStop a lane once its task lands or parks, so it stops counting against the cap.
• Make lane worktrees yourself (git worktree add); isolation: "worktree" branches from the default branch, not your base. Keep your own shell at the repository checkout: your working directory persists between Bash calls and every lane you dispatch inherits it. Never cd into a worktree; use git -C <worktree> and absolute paths, or a subshell (cd <worktree> && ...). If pwd is not the checkout, cd back before the next dispatch. Lanes never call EnterWorktree.
• A lane’s hand-back is one-shot. After a resume, its next return may arrive as an agent message instead of a task notification: take the lane-return block in it as the return. If a resumed lane goes idle with neither, read its return.md.

Waits

• Your own waits (main CI, a release, a gate you run) are one run_in_background Bash command whose until loop exits on every terminal state; its completion wakes you. Streamed events use Monitor, re-armed when it expires.
• LOOP.md’s optional ci-status command replaces gh reads: substitute the full SHA for {sha}, sleep 60 s between reads, stop on success or failure, bound the loop by ci-max-minutes (default 30).
• A composed gate’s legs (contract section 6): after the git status --porcelain check, start each leg as its own run_in_background Bash command against the compose worktree by absolute path, one log per leg. If the classifier refuses the fan-out, record the denial, run the legs one after another and say so in the return or DECISIONS.md.
• Bash calls time out at 10 minutes: run anything longer in the background. Never a foreground sleep over 60 seconds.

Turn endings

A message with no tool call ends your turn, and the loop stops there until the operator returns.
Do not end a turn with a summary that announces the next step without taking it, an offer to carry
on, a list of decisions none of which blocks the remaining work, or a decision that this is a good
place to stop. Put status notes in the same message as your next tool call. End a turn only when the
closeout is written, when paused, or when a running background command, monitor or lane will wake
this session; when waiting, make the last line `WAITING: <what> until <YYYY-MM-DDTHH:MM[:SS]Z>`;
when paused, `PAUSED: <reason>`. Never TaskStop a lane mid-mutation.