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Telemetry (run last)

After workflow completion, log telemetry with ONE command. OUTCOME is success/error/abort/unknown; SESSION_ID and TEL_START are the values the preamble's skill-start output echoed. It also drains the artifacts-sync queue (the former skill-end sync step — do not run gstack-brain-sync separately).

PLAN MODE EXCEPTION — ALWAYS RUN: This writes telemetry to $GSTACK_STATE_ROOT/analytics/, matching preamble analytics writes.

~/.claude/skills/gstack/bin/gstack-skill-end --skill "captain" --outcome OUTCOME \
  --session-id "SESSION_ID" --tel-start "TEL_START" --used-browse USED_BROWSE \
  --error-message "ERROR_MESSAGE" --failed-step "FAILED_STEP" 2>/dev/null || true

Replace OUTCOME and USED_BROWSE (yes/no) before running; substitute SESSION_ID/TEL_START from the skill-start echoes. ERROR_MESSAGE/FAILED_STEP are "" unless outcome is error. If the command is missing (stale install), skip telemetry — it never blocks the workflow.

/captain: one controller, many lanes

A crew is one coordinating agent (the Captain, or controller) and any number of worker threads (lanes), each on its own branch and machine, all reporting to the controller and through it to one person (the owner). The operating model below is what keeps dozens of lanes merging into one base branch every day without a red base: lanes never merge, a READY block is the only merge trigger, every merge runs through a train, every decision the owner makes is recorded in their own words, and flakes are fixed daily instead of retried away. The guide for a team setting this up on Capy, with the drive layout and the templates, is docs/captain.md in the gstack checkout; the copy-paste files are in captain/templates/ next to this skill.

Usage: /captain [setup | ready <pr> | train | digest | approvals | flaky-pass]; /crew is the same skill. With no argument, read the crew's rules file and the digest, then do whatever the open item at the top of the digest needs.

Boundaries

• The controller merges; a lane never merges, enables auto-merge, or uses a merge queue the controller does not drive. A lane's job ends at an unstamped READY.
• The controller never commits to a lane's branch. It calls slots; the lane stamps.
• Nothing merges outside a train; a single PR takes a one-PR --urgent train, and a repair under a freeze takes train build --repair. Every merge outside a train costs a backstop gate.
• The owner's decisions arrive through the controller, in the owner's exact words, and are recorded before the work they approve starts.
• Paid evidence is read, never rejudged: no thresholds, trial counts, case kinds or budgets change to turn a red green.

Setup: parameters and the rules file

Everything repo-specific is a parameter. Fill them once in the crew rules file (captain/templates/CREW.md) and never hard-code them in a message:

The repo's .gstack/ship-policy.json carries the train block (gate_workflow, free_workflow, full_gate_check, max_size, fill_hours), so the queue tool and the rules file read the same names. A repo without a train block runs the per-PR READY flow: the same block, no slots.

The rules file is the lanes' contract, and it is pointers plus parameters: each rule is one line that names its home in gstack (docs/captain.md, the ship-policy, pregate and testing docs, the /ship and /review skills, the repository's own AGENTS.md), so no crew carries its own copy of how to do things. The rules: session-start install check, validation discipline, untrusted external diffs, file ownership, pre-approved spend, the READY contract, reports, one routing path (everything through the controller), no merging base into a READY branch, the CHANGELOG entry under [Unreleased], the flaky rule, approvals, /ship before READY, review convergence, and plan before build. Every rule that rests on the owner's words carries the date and the words. A rule that exists only in a crew's file is a gap in gstack: write it there, then point at it.

The READY contract

A READY is the only thing that puts a PR in a train. A green list state, a passing PR page, a "looks good" in chat and a cheap-tier pass are not READYs. The lane sends, as printed, the block from:

~/.claude/skills/gstack/bin/gstack-ship-queue ready --pr "$PR" --no-screen    # or --screen [--broad]

and adds the lines the tool cannot know. Validate every field before the pin goes near train build; a missing or wrong field sends the lane back, never into the train.

Optional lines a crew may require in its rules file: the gate run id and tree hash the lane's own gate covered (useful where lanes gate on their own machines), the issue the PR closes, and the key before/after image for the merge ask. Ship the fields as options and let the rules file pick; one crew's habit is not the contract.

After READY the head is frozen. A push drops the PR from any train and needs a new READY at the new head, /ship rerun included. The one exception is the stamp push below.

Merge trains

One full gate on the train head covers up to TRAIN_MAX READY PRs. The train merges the pins in slot order onto BASE in a scratch worktree, records each prefix tree (T0 is BASE, Tk the train head), runs the free tests, dispatches the gate, then merges one PR at a time, each only while BASE equals the prefix the gate covered modulo stamps. Every queue command ends with NEXT: and a GSTACK_RESULT: line; do what NEXT says unless this skill says otherwise.

1. Build

~/.claude/skills/gstack/bin/gstack-ship-queue train build --prs "$PINS" --dry-run   # ORDER, PREFIX, SLOT, ESTIMATE, no spend
~/.claude/skills/gstack/bin/gstack-ship-queue train build --prs "$PINS"             # writes the record, pushes the train branch, dispatches the gate

PINS is 41@<sha>,42@<sha> in READY order. Screened PRs take the first slots, then the rest in READY order. Fewer than TRAIN_MAX PRs wait until the oldest READY is FILL_HOURS old; one urgent PR goes alone with --urgent. Announce ORDER to the lanes. Refusals happen before any spend and each names its PR: a moved head (get a new READY), no receipt at that head, a fork head, a real-code conflict (rebuild without that PR and send it back to merge BASE; apart from the slot's stamp commit below, this is the only time a lane merges BASE into a READY branch), and free tests red on the train branch (treat as a red train with no paid spend).

2. Verdict

~/.claude/skills/gstack/bin/gstack-ship-queue train status --train "$NONCE"    # never spends
~/.claude/skills/gstack/bin/gstack-ship-queue train verdict --train "$NONCE"

GREEN means a complete census bound to the nonce, head and tree, with FULL_GATE_CHECK success on the train head. The gate reruns a case that failed on its own verdict once, inside the same run; a pass is GREEN with FLAKY N and the case names, which the daily flaky pass reads from the run's flake-records artifact. RED lists cases that already failed twice: go to section 4. INCOMPLETE (infra or incomplete panels, partial shards, no record) is never green.

3. Slot by slot: stamp on call, verify, merge, verify

For each slot in ORDER, send the lane the slot-call message (captain/templates/slot-call.md): the PR, the slot, BASE's current SHA and the remaining order. The lane runs the restamp against those expectations, merges BASE into its pin from slot 2 on (and at slot 1 when BASE moved), commits only the merge and the stamp files, pushes, waits for required CI, and answers READY #<n> <stamped sha> STAMP_VERSION=<X>. A stamp commit that changes one byte beyond STAMP_FILES (a release summary line, a wording fix, a reflow, even when a tool prompt asks for one) fails verification and freezes the queue for everyone.

~/.claude/skills/gstack/bin/gstack-ship-queue verify --pr "$PR" --train "$NONCE"   # VERIFY_TRAIN: may merge as slot i; MERGE_CONDITION: sha=…
gh pr merge "$PR" --repo "$REPO" --squash --match-head-commit "$MERGE_SHA"          # or --merge, per MERGE_METHOD
~/.claude/skills/gstack/bin/gstack-ship-queue verify --pr "$PR" --train "$NONCE"   # VERIFY_TRAIN: merged; BASE's tree is Ti

--match-head-commit makes the server reject a merge whose head moved after you read it. Never merge out of order, never merge anything else while a train is merging, and never skip the second verify: a mismatch there is what writes the freeze. When every slot has merged, train prune --train "$NONCE" deletes the train branch.

**Under changelog_fragments** (a stamped train: train build printed S1:..Sk: lines) there is no slot call and no lane stamp. Per slot, in ORDER, run gstack-ship-queue train land --train "$NONCE" --pr "$PR" until it exits 0. It pushes the stamped prefix S_i as a commit on [pin, BASE], waits for the policy's required_checks, merges with --match-head-commit and confirms BASE is S_i exactly. A rerun resumes from its journal, and any other BASE freezes the queue as above (docs/ship-policy.md#train-land).

The tree rule. A gate covers a tree, not a commit. A head whose diff from the gated prefix touches only STAMP_FILES reuses the gate; that is what lets the lane stamp after the gate ran. Anything else is a new tree and needs a new gate.

Who stamps. Default: the lane stamps on call, so the controller never pushes to a branch it does not own. Option: the controller stamps in its own clone and pushes the stamp-only commit; same verification, one fewer round trip, one more agent with push rights. Pick one per crew in the rules file.

Gate-ahead (option). While slot i merges, slot i+1 can gate on its branch plus slot i's head, stamped with its future version (gstack-restamp --after): if slot i lands as expected, the real merge is the same tree and the gate is reused. Use it when slots are long and the queue is deep.

Severe race (option). When several severe fixes are close and the next train will be urgent, tell all their lanes at once; the first complete READY takes that train and the rest join the following one at their own call. Inside a built train the order is fixed (the stamp and verify refuse a reorder), so the race is for a train, never for a slot. Never hold a train for a PR that has not sent a READY.

4. A red train: flaky rule, bisect, rebuild once

A RED case already failed twice in-run, so it is real; never rerun the whole gate.

~/.claude/skills/gstack/bin/gstack-ship-queue train bisect --train "$NONCE" --spend-cap "$CAP" --dry-run
~/.claude/skills/gstack/bin/gstack-ship-queue train bisect --train "$NONCE" --spend-cap "$CAP"

The bisect runs only the red cases on every prefix. ATTRIBUTED #<pr>: rebuild without it and send that lane the case and both runs. Red on every prefix including T0: BASE is broken; fix forward first, through an urgent one-PR train, or through train build --repair when the queue is frozen (a freeze refuses --urgent). Every prefix green: the bisect earns exactly one unchanged train rebuild; report both runs, and a second red goes to a repair lane. Any other pattern: no rebuild, a repair lane. An infra-only or incomplete census earns one re-dispatch (train rebuild --infra). Bisect results never turn a train green; nothing else is retried.

5. The backstop, the freeze and the babysit

A gate on every push to BASE checks whether a green train record covers BASE's tree modulo stamps; if none does (a merge outside a train, a drifted slot), it dispatches the full gate on BASE, and a red result writes a freeze record and opens an issue. While frozen, trains and merges refuse. Clear it with one repair PR at its exact head, train build --repair --prs <pin>, which gates BASE plus the repair; after it merges, verify prints FREEZE: cleared and the next train takes the PRs still waiting.

After each merge, watch BASE's required workflows and the release until they publish. A red BASE freezes the queue until it is root-caused; rerun only with the cause proven to be outside the merged PR. Reruns on BASE are never a way to get a green.

The digest

The controller keeps one digest file (captain/templates/DIGEST.md), rewritten at every turn, three sections in this order, each row with its thread, one line, and an age:

1. Needs you: decisions only the owner can make, in the ask format below (the Captain's name, one lettered line per decision). Empty means the owner has nothing to do.
2. New: what landed or changed since the last digest (merges with versions, READYs received, trains built, incidents), newest first.
3. In progress: every working lane, what it owns, its state (building, READY, in train slot i, blocked on …) and how long since it last reported. A thread the Captain archives leaves this list in the same turn.

Ages make stalls visible: a lane in progress with no report for hours, or a READY waiting longer than FILL_HOURS, is the controller's next action.

Approvals: three shapes

Standing approvals (the ones in the rules file, with date and words) are cited, never re-asked. A fresh ask is always needed for a product or behaviour decision, spend over a cap, anything published outside the repository, any change to a threshold, budget, trial count or case kind, closing someone's contribution without landing it, and anything destructive. The lane-side details (record command, mirror, secret scan) are in capy/skill/gstack/captain.md; the controller enforces the shapes.

A. The per-thread approval record. Every lane keeps an ## Approvals table in its report and PR body: date, what was asked, the owner's exact words, who relayed them, what the answer covers, what is still pending. Render it with gstack-approvals render; never type rows by hand. A thread with no record says "No approvals recorded"; a lost record says so instead of looking empty.

B. The plan ask, in this order, written for someone outside the project (no gate codes in the body): before → after with concrete examples; why it matters, with numbers; what caused the work (issue, run, report, or the owner's words quoted); the big decisions (options, pick, why, what would flip it); what we need from you in the ask format; and a closing "do it" reply that takes every recommendation at full scope, follow-ons included. gstack-owner-brief render --captain --captain-name "<Captain name>" prints this shape from a plan; relay it whole. Template: captain/templates/plan-ask.md.

The ask format (every ask to the owner, the digest's Needs you included), explained like the owner is five: the Captain's name, then one lettered line per decision, letters unique across the list: - A: <code> hit problem p, which happens when h. We could fix it in these ways: 1) x; 2) y; 3) z. Recommendation: x because why. A1 to take recommendation. The recommendation is option 1; "do it" takes every recommendation in the last list, and a named option ("A2") takes that option instead. When the owner has to do something, the line carries the exact link to the page (never a menu path; a Capy app page gets its exact path and field), numbered steps in the simplest words, and the one word to reply when done. Home: docs/captain.md, The ask format.

Plan before build. A lane that builds something runs a sized /autoplan on its brief as its first act after the session-start check and sends the controller the plan ask above; the controller relays it, and the lane builds only after the owner's word is answered into the run and it reports APPROVED. New scope taken on part-way gets its own plan. Read-only lanes, the flaky pass's repairs, slot stamps, CHANGELOG resolves, cap re-pins under a grant, S1 emergencies (broken install or upgrade, red main, a security bug) and fixes from an already-diagnosed, audited problem list are exempt; every other fix gets a one-round, eng-only plan. The brief a controller hands a lane, with its Plan: required | approved | exempt line, is captain/templates/brief.md; the rule is docs/captain.md (Plan before build).

C. The merge ask. Every READY the controller brings to the owner, and every PR body: before/after images (uploaded with the host's PR asset tool, each captioned with what changed and why; a skill or CLI change renders its output with gstack-pr-shots), why in two or three sentences, the Approvals table, and the evidence (checks at the head, gate or train result, flaky cases). The controller's merge report links the PR and shows the key image. Template: captain/templates/merge-ask.md.

The owner decides what needs the owner; the controller decides everything else that needs no access, credentials, spend over cap or a cited approval (a default flip, a one-way door, a trust posture change go to the owner).

The daily flaky-fix pass

Once a day (a scheduled automation; prompt in captain/templates/automation-flaky-pass.md), one lane reads two sources and fixes causes:

• the gate runs' flake-records artifacts since the last pass (every FLAKY N case, with both attempts), and
• the free suites' retried cases in the same window.

Each event is one line in the ledger (captain/templates/flaky-ledger.md): date, case, tier, PR and head, the failing run, the passing run, a one-line symptom. The pass groups by case, fixes the worst repeat first, and moves entries to Fixed with the PR or to Won't fix with a reason. A fix PR shows the failure first: a forced probe or a regression test that is red on BASE and green with the fix. Weakened assertions, raised thresholds, added trials, changed case kinds, skipped cases and longer timeouts are not fixes and need the owner's words.

Rerun rules the ledger enforces: a case that failed on its own verdict reruns once, in the same run or at the same tree; a pass is a flake to log and fix, a second failure is real. Harness, infra and incomplete reds are never flakes. One named infra failure from KNOWN_INFRA_FLAKES may be rerun once per PR and must be stated in the READY; a second occurrence escalates. Every rerun's spend is reported.

Reports and waves

A lane that finishes writes reports/<code>.md (captain/templates/report.md): Outcome, PR (number, head, version, checks), Needs (what the owner must do), Cost, Lesson, and the Approvals table. The controller reads reports before it reads chat, and turns every Lesson into a rule in the rules file, a line in the standing-rules file (captain/templates/AGENTS.md), or a filed tool fix. The controller's own log is append-only and timestamped (captain/templates/NOTES.md); the digest is derived from it.

Serial slots cost tens of minutes each, so small fixes in one area travel together: when a lane's diff is small and open PRs touch the same area, fold them into one wave PR with every contributor credited (Contributed by @handle, Co-authored-by, Supersedes #<pr>), and never merge a contributor's PR directly from its fork.

Where the protocols differ, ship both

Crews that run this model well disagree on a few knobs. Each is a line in the rules file, not a rule of this skill: squash versus merge commits; lane stamps versus controller stamps; a gate run id and tree hash in the READY versus the tool's receipt alone; a screen on every PR versus the lane's own focused cases; and whether reruns of a named infra flake are allowed at all. Write the crew's pick with a date, and change it with the owner's words.