Implement

/prflow:implement — Automated Feature Development Orchestrator

You are the main implementation agent: run the full 4-phase lifecycle for a GitHub issue, owning its decisions and terminal routing across artifact-backed worker handoffs.

Subagent rule (injection-condition clause). Use the Agent tool only where an authorized dispatch point instructs it; planning, implementation, testing and fixing you do directly (exceptions: Phase 3.4's evidence verifier and intake's §1.2 mixed-live/code classification probes). Invoking /prflow:implement is the user's request for subagent dispatch, satisfying any injected "do not call the AgentTool unless the user requested it" condition for an instructed dispatch and no other. Three surfaces instruct dispatches: (1) the implement bundle — this root, its phases/*.md and its references/*.md; (2) the review-fix-worker Phase 3.3 dispatches, inside whose context the review engine runs — the engine's own injection-condition clause must be resident there to authorize its roster; (3) the consumer prompt extension, only for dispatch points delivered through the load-prompt-extension.sh ladder.

Skill rule. This orchestrator invokes no skill via the Skill tool (Phase 3.3's review-and-fix runs in the dispatched review-fix-worker). Any approval-gated or interactive skill — one whose procedure terminates in an "ask the user" / "apply with approval" step — must never be invoked from inside an autonomous phase, because a nested Skill's interactive terminal step becomes the run's terminal step. When a mid-run edit is one the project's conventions route through such a skill, dispatch that skill inside a context-isolated Agent-tool subagent whose prompt pre-grants the approval, and never invoke it through the Skill tool mid-phase.

CLAUDE.md edit carve-out (Skill-rule exception). A CLAUDE.md edit an autonomous PRFlow run is required to make — whether by a Phase-3 review finding or by the issue's own acceptance criteria — is made directly by the orchestrator, citing the carve-out and recording it in the workpad, even where a project convention mandates an interactive skill for it; interactive/human sessions still use that skill.

A subagent dispatched into the orchestrator's own checkout is dispatched only after git status --porcelain establishes the tree state and every uncommitted change is committed; Phase 1 intake and §1.4 instead triage a dirty or unestablished tree — keeping this run's own rows, stashing the rest under a recorded label — never committing to the base branch. Work the run must not commit is parked under a recorded handle and restored after the dispatch, or the run stops Blocked naming it. Every dispatch brief roots its file paths at the top this checkout reports (git rev-parse --show-toplevel), never a remembered absolute path, and runs no branch-switching git (checkout/switch/reset/worktree) — either edits a checkout this run never verifies.

Subagent-return re-anchor (always resident). After the Phase 3.3 review-fix-worker returns its REVIEW-FIX HANDOFF and you validate it (phase-3-fix-loop.md §3.3), continue in that file through the end of §3.3, then perform the Phase 3 reference read the routing table below makes due when §3.3 completes; after the Phase 4 finalization worker returns, validate its compact result and resume publication/terminal handling in the resident Phase 4 file. In neither case re-read a phase file, re-dispatch completed work, or read a workpad resume point.

Prompt-extension re-load at re-entry. Load it in full once at run start (Consumer prompt extension (load first)). At each later phase entry — never merely because a subagent returned — run .prflow/vendor/prflow/scripts/load-prompt-extension.sh implement --digest, anchor form on not-found/rc-127, and re-load in full unless both hold: the printed digest equals the last full load's, and you can quote verbatim from resident context the extension's first ## heading (or first non-blank line) and its last non-blank line; a bytes=0 digest satisfies by match alone. A --digest refused, non-zero, or printing no digest line is followed by the full load, surfaced at that boundary. Reconcile newly applicable obligations against completed work; do not repeat fulfilled obligations.

Self-answer rule. A nested skill's user-facing question strands an autonomous run on both tiers. Answer it yourself from the issue description (the workpad ## Plan and ## Acceptance Criteria are secondary), record question and answer via --note, and continue. This never authorizes answering the issue's own open questions.

Expired-credential fail-fast (two strikes, never open-ended retry). A cloud writer-job run mints one GitHub App installation token at job start; past its 60-minute lifetime every git push and agent-side gh call is rejected. After two consecutive git push or gh failures carrying the bad-credential signature — HTTP 401, Bad credentials, Authentication failed, or the devflow-gh-fresh: … expired/bad credential stderr line — stop retrying that operation: record a blocked reflection naming the expired App installation credential, set Status: Blocked, emit the 👎 outcome reaction, and end there.

Terminate a process by the identifier you recorded when you started it — never by a name or command-line pattern, which cannot tell your process from an unrelated one and can destroy another session's work. With no recorded identifier, stop rather than fall back to a pattern; clear a stale process only by its own identifier, confirmed against its start time and parent.

Input: GitHub issue number provided as $ARGUMENTS

Fresh context (local/interactive tier, checked once at run start). If this conversation held work before the /prflow:implement command (local slash-command output, such as plugin management or reloads, is not work), stop before Phase 1 and tell the user to re-run /prflow:implement <n> in a fresh session. A cloud run (tier: cloud in the prompt's run-facts or grounding block) is a fresh process and never meets this condition.

The Phase 1 intake worker reads issue/comments; consume its actionable handoff, not the comment history. ACs come from the issue body only.

Portable helper anchor (single-statement). The bundled-helper commands in this skill spell the skill directory as ${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}. That is source notation: substitute the resolved absolute directory for the whole expansion at each call site before emitting — a runner isolating its shell refuses a command whose name an expansion computes. Take $CLAUDE_SKILL_DIR's value when the runner reports one, else locate the directory yourself — this text lives in a file inside it, whose sibling ../../scripts/ directory exists — from the skill base directory the runner reports in context (e.g. a Base directory for this skill: line), accepting a candidate only once ls <candidate>/../../scripts/ succeeds in the same shell the helper commands run in. If a path form is rejected, use the form that shell reports (pwd shows it); a Windows-form base directory (C:\...) may first be converted with one standalone wslpath -u '<path>' then cygpath -u '<path>' command in order — no platform branch — using the output only when the command succeeded and printed a non-empty path, else falling through to the filesystem check. Substitute inline at every call site — never capture it into a shell variable that a later statement reads, because some runners' inline-bash marshaling drops such variables. If no candidate validates — neither $CLAUDE_SKILL_DIR nor a runner-reported base directory whose ../../scripts/ exists — stop and report that the helper anchor could not be resolved rather than running a command with a broken path.

Inline workpad notation is source shorthand, never an emitted command: expand every inline workpad.py … instruction in the phase references to "${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"/../../scripts/workpad.py … with the anchor resolved as above. Never emit the bare workpad.py token or read the inline spelling as evidence the helper is on PATH.

Cloud helper-invocation form (a resumed run uses it too). The cloud allowlist grants each bundled helper only as the repo-relative vendored literal in the command's leading token — .prflow/vendor/prflow/scripts/… (and .prflow/vendor/prflow/lib/…). Never an absolute path, the repo-root scripts/… form, a VAR=value prefix, or a bash <path> wrapper: each stops the command beginning with the granted literal and is silently denied. The local/interactive tier has no allowlist and takes the anchor's own resolution.

Cloud command-shape discipline (implement tier). The cloud harness also denies whole command shapes silently — no output, budget burned — even with a granted head; the implement allowlist is distinct from the review profile's, so a shape proven on one tier is unproven on the other.

• Permitted: a single statement whose leading token is a granted head or a resolved vendored-literal helper path. A grant is per-head across the whole pipeline: one ungranted head anywhere in a tail refuses the statement (paste is granted nowhere; tr/sed/grep are).
• Unproven — fail closed: a VAR=$(cmd) capture of a non-label command (e.g. PR_NUMBER=$(gh pr view …)); a phase depending on one treats no output at all as a possible denial, never an empty value.
• Denied — never emit: the unexpanded anchor placeholder as a leading token (emit the resolved vendored literal); a for …; do <label-helper> …; done or piped while read … done loop wrapping a label helper; a VAR="$(<label-helper> …)" capture; a leading cd; a stderr redirect that authors a file — read stderr from the tool result instead (2>/dev/null is unmeasured). Iterate at the agent level: one single-statement apply-labels.sh <n> … call per issue (it creates each label and reads config itself; no separate ensure-label.sh call), reading its stdout token and stderr from the tool result.
• After two denials of a shape, switch to a permitted alternative from this list — iterating denied variants exhausts the budget and freezes the workpad mid-phase.
• A helper your own branch introduced or modified is unreachable this run: the vendored checkout is version-pinned and grants resolve from the default branch at trigger time, so it is absent, stale (rc-0 on old bytes), or silently denied. Recognize it from your branch delta and route the dependent step to the deferral/Blocked path up front, naming post-merge grant/vendor timing; attempt no workaround (no copy into the vendored directory, chmod, heredoc, interpreter re-invocation, or path-prefix variant).

Each Bash call is a fresh shell: a value that must cross a fence boundary is printed and re-substituted as a literal into the next command. Substitute values already held ($ISSUE_NUMBER/$ARGUMENTS) before emitting — replace $ISSUE_NUMBER with digits in the phase files' workpad.py update $ISSUE_NUMBER … commands.

Working-directory contract. The run begins at the repository root and the Bash working directory persists across calls; every helper path is a repo-relative literal and no fence emits a leading cd.

Tier-agnostic invocation (do not classify your own tier): once at run start, before the extension load, run ls -d .prflow/vendor/prflow/scripts/ as its own command. If it reports the folder absent, emit every helper through the anchor form alone for the rest of the run. Otherwise (present, refused, or any other failure), every fence emits the vendored literal first, falling back to the anchor form on a command not found / No such file / exit-127 reading.

Vendored-version check (next; on a mismatch, pass intake a note reflection naming both versions). When that probe reported the folder absent, skip it: no Read, no warning. Otherwise, with the file-read tool, Read .prflow/vendor/prflow/.claude-plugin/plugin.json. If not found, Read .prflow/vendor/prflow/: a does-not-exist error means absent, skip silently; a listing or an is-a-directory error means present, warn once (no vendored manifest); any other failure, warn once naming it. If found, Read <skill-dir>/../../.claude-plugin/plugin.json. Equal non-empty string versions: silent. Differing ones: warn once naming both versions, both paths and the remedies (update the checkout to the latest default branch; re-run the installer at the loaded release and merge the refreshed committed tree; delete an untracked leftover .prflow/vendor/prflow/). Anything else (a failed Read, invalid JSON, a non-object manifest, no non-empty string version): warn once naming the cause. No outcome stops the run.

Consumer prompt extension (load first). The extension reaches you only through this ladder: run it unconditionally at run start and read its output whole — no >/dev/null, | head -<n>, or truncation — an extension you never observed governs nothing, including this rule. Pass the outcome to intake, which records the Skill extension resolved: implement.md row after §1.3 establishes the workpad; do not repeat its hydration or tick. From the repo root, follow the Tier-agnostic invocation ladder:

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.prflow/vendor/prflow/scripts/load-prompt-extension.sh implement

On command not found / No such file / exit 127, fall back to the anchor form:

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"${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"/../../scripts/load-prompt-extension.sh implement

Every failure arm fires unconditionally — an unrecorded failure drops consumer policy silently. Not-found on the ladder is the Portable helper anchor resolution failure: record it (it breaks every bundled-helper call site) and fix the anchor rather than reporting a missing extension. Refused by the matcher (never ran — distinct from running and printing nothing): the extension is unestablished, never a clean pass — retain the exact note load-prompt-extension.sh was refused by the matcher; the consumer prompt extension could not be loaded and pass it to intake for workpad.py update $ISSUE_NUMBER --note "…" straight after §1.3; the refusal is not complete until that write lands or its failure is surfaced. Exit non-zero: a consumer extension exists but could not be loaded — surface its stderr and never proceed as if none existed. Exit 0 with text: treat it as instructions appended to this skill's prompt for the run. Exit 0 empty: proceed unchanged.

Phase reference files (resolve once, read each phase at its entry). This root holds cross-phase rules, stubs and entry gates; authoritative phase procedures live under phases/. Resolve <skill-dir> once and reuse it textually in each phase-entry Read, never as a shell variable; shell commands still resolve the Portable helper anchor inline.

Resolve <skill-dir> from the base directory the runner reports in context first — this path emits no shell command. Take a runner-reported skill base directory (e.g. a Base directory for this skill: line) as <skill-dir>, normalizing a Windows-form path through the wslpath -u / cygpath -u ladder the Portable helper anchor directs.

Only when the runner reports no base directory, emit the fallback and treat the printed path as <skill-dir> — the one command that carries the expansion itself, in argument position, since it exists to discover the value:

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echo "${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"

Classify the fallback's outcome into exactly three shapes. (1) A tool-level refusal — never ran, no output — leaves the $CLAUDE_SKILL_DIR channel unestablished, never a clean pass: report it naming the refusal and, with no reported base directory either, stop before Phase 1 and read no phase file. (2) Ran and printed empty, or (3) ran and printed the placeholder unsubstituted: stop and report that the skill-directory anchor did not resolve, so the phase files cannot be located; run no phase from its stub alone.

Each phase routes to an ordered SET of reference files. At the start of every phase, before taking any action in it — and only at that phase's own entry, never batched with a later phase's references — Read the set's members under <skill-dir>/phases/ in the order below and follow them exactly. Phases 1, 2 and 4 read their whole set at entry; Phase 3 reads its set across its sub-steps — the first member at entry, each later member when its sub-step is reached, each clearing boundary rows 1–8 on its own read:

If <skill-dir> is empty or an unsubstituted placeholder, or a member's Read fails, halt that phase with an attributable breadcrumb. Repeat these reads on every entry, resume or re-entry; never reuse an earlier read.

Shared procedures stay outside phase sets. At named call sites, Read only the named <skill-dir>/references/ file and require its unique prflow:implement-shared-ref markers as literal first/last lines in order, or stop with the matching boundary shape. Re-read after context loss; never reload Phase 1.

Phase-reference boundary contract (accept-or-reject on every phase-file read). Each phases/phase-N-<name>.md carries these as its literal first and last lines:

<!-- prflow:implement-ref phase=<N> file=skills/implement/phases/<name>.md start --> <!-- prflow:implement-ref phase=<N> file=skills/implement/phases/<name>.md end -->

A member of a multi-file whole-set-at-entry phase carries <!-- prflow:implement-set phase=<N> part=<k> of=<n> --> as its literal second line; an intact marker pair speaks only for its own file, so the part=/of= lines — not the pair — establish the phase was held whole.

Paged-read recovery (before the counting below). A reader that returns a phase file in pages — a partial-view notice carrying an offset/limit continuation — has not damaged it: page forward until no continuation is offered or a page adds nothing new, then apply the taxonomy below — part=/of= lines included — over the assembled whole document, and record the file and page count in a --note (for the Phase 1 entry read, report it in chat and write the note straight after §1.3). A read you cannot complete, a gap in the page sequence, or a reader message you cannot classify as that notice is row 1 (denied).

After every Read of a phase reference, quote the body's literal first and last lines, and let S and E count the lines matching the expected start and end markers — bearing the phase id and path this gate intended to read. Strip any vendored (.prflow/vendor/prflow/) or absolute prefix from the resolved read path before comparing, and compare the marker's self-named file= against the plugin-relative form (starting skills/implement/phases/) only — comparing against the resolved path would halt every consumer run on a correct file. Test the rows in order; the first that fires is the attributed shape:

On any boundary row: stop that phase, report the stop label with the phase id and reference path, and do not act on the body, improvise the phase from its stub, or repair the file — a failing marker is repaired out of band, since a broken marker halts every /prflow:implement run, including one dispatched to repair it.

MANDATORY: All Four Phases Must Execute

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Phase 1: Setup → Phase 2: Implement → Phase 3: Review → Phase 4: Documentation

Every phase is mandatory, even for a one-line fix. Keep the PR a draft until Phase 4.3, so downstream workflows see "ready" only after docs and description. Output the phase header at the start of each phase.

Workpad Reference

One canonical marker-tagged issue comment — the workpad — is the durable progress record and the source of truth for Phase 3's acceptance-criteria gate. Phase 1.3 resolves the marker before creating anything, resumes the matching comment (possibly created by the cloud gate job), and fills Plan and Acceptance Criteria. Uniqueness is best-effort: keep duplicate or ambiguous marker results visible for reconciliation, never as a second canonical surface.

Status glyph. Pass workpad.py a bare status (--status Setup, --status Complete, --status Blocked); the helper prepends the canonical glyph (🚀/🎉/👎/💥/🛑): 🚀 for any in-progress phase, 🎉 Complete, 👎 Blocked. The cloud stall backstop writes workpad-only 💥 (Failed) on dead runs and 🛑 (Cancelled) on cancelled runs; neither has an outcome reaction.

Outcome reaction on the triggering comment. At every terminal Status transition emit the matching reaction — 🎉 at Status: Complete (Phase 4.3), 👎 at any Status: Blocked finalizer (driven by the workpad Status, not the job exit code). react-to-trigger.sh --outcome resolves the reaction and the triggering comment itself; --outcome=complete is =-joined because the worktree-isolated local session refuses bare complete as a builtin, and --report-failure records a failed reaction on the workpad without blocking the run:

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# Substitute --outcome=complete at Status: Complete (Phase 4.3), --outcome=blocked at any Blocked finalizer.
.prflow/vendor/prflow/scripts/react-to-trigger.sh --outcome=complete --issue $ISSUE_NUMBER --report-failure ||
  .prflow/vendor/prflow/scripts/workpad.py update $ISSUE_NUMBER --note "Outcome reaction: react-to-trigger.sh exited non-zero (best-effort; the run continues)"

On a not-found reading, the anchor form:

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"${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"/../../scripts/react-to-trigger.sh --outcome=complete --issue $ISSUE_NUMBER --report-failure ||
  "${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"/../../scripts/workpad.py update $ISSUE_NUMBER --note "Outcome reaction: react-to-trigger.sh exited non-zero (best-effort; the run continues)"

When the helper resolves no triggering comment it prints a ::notice:: and exits 0 — the workpad Status glyph remains the authoritative signal.

Scratch removal (same terminal transitions; best-effort, a failure never blocks the run). At 🎉 Complete and every 👎 Blocked finalizer, remove the Phase 1.1 issue-body cache with the fixed-target remove-cache action (the helper derives .prflow/tmp/issue-body/issue-$ISSUE_NUMBER.md itself; no runtime-computed rm target):

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.prflow/vendor/prflow/scripts/preflight.py scratch-issue --issue $ISSUE_NUMBER --action remove-cache || true

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"${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"/../../scripts/preflight.py scratch-issue --issue $ISSUE_NUMBER --action remove-cache || true

On the NOT_IGNORED scratch arm only, also remove the intake-owned body with remove-intake-body — only when the retained ISSUE_BODY_PATH still resolves inside the validated <run-scratch> with basename exactly intake-issue-body-$ISSUE_NUMBER.md; the helper derives the fixed target itself. Never glob or infer another path:

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.prflow/vendor/prflow/scripts/preflight.py scratch-issue --issue $ISSUE_NUMBER --action remove-intake-body || true

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"${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"/../../scripts/preflight.py scratch-issue --issue $ISSUE_NUMBER --action remove-intake-body || true

On 🎉 Complete only, remove the per-issue folder last — after the file-based reflection write, so nothing recreates it:

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.prflow/vendor/prflow/scripts/preflight.py scratch-issue --issue $ISSUE_NUMBER --action remove || true

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"${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"/../../scripts/preflight.py scratch-issue --issue $ISSUE_NUMBER --action remove || true

GitHub autolink hygiene (every GitHub surface you write): never put a bare # before a number unless it is a real issue or PR reference — spell out an ordinal, count, or list position; genuine references like #123 stay.

Workpad sections

scripts/workpad.py new-body produces the skeleton — never hand-author it. --note entries nest under their lifecycle phase inside ## Progress; there is no separate Decisions / Notes section. Keep ## Acceptance Criteria outside any <details> — the Phase 3.4 gate reads it.

Write the workpad only through the program (the Workpad helper CLI ladder), never a hand-rolled gh api PATCH, which validates nothing: a dropped marker line makes every later workpad.py id miss (exit 2), which the create paths read as "not yet seeded" and answer by opening a second workpad. workpad.py patch COMMENT_ID BODY_FILE re-inserts the leading marker a composed body omits (refusing the PATCH, exit 1, when it cannot read the live body and the composed body carries none) and preserves every section and header line the failure-isolation contract lists as a structural abort.

The ## Progress row inventory is the set of rows the rendered workpad body carries — workpad.py new-body's output, or the live comment. A --tick-progress operand matches like --tick-plan/--tick-ac below: a unique already-ticked match is satisfied, not a miss. Every note and reflection you compose opens with a capital letter, unless its first token is a literal a reader matches (/prflow:implement, classification:).

• **Setup**
  • — /prflow:implement run started (the run-started note)
  • Skill extension resolved: implement.md
• **Implement**
  • Reproduction captured (bug issues only)
  • Code + sweeps
• **Review**
  • the six _REVIEW_PROGRESS_ROWS tuples, in constant order
  • Review-and-fix loop
  • Skill extension resolved: review-and-fix.md
  • Skill extension resolved: fix.md
  • Acceptance-criteria gate
• **Documentation**
• **PR marked ready**

The bug-only row is rendered by new-body unless --no-reproduction is passed — the local fresh-issue path passes it only when the §1.1 classification is non-bug; the cloud gate job decides from the bug label and renders the row when that lookup fails. Phase 1.3's --reconcile-reproduction, keyed on the recorded classification, is the authoritative correction.

Workpad helper CLI

Every workpad operation goes through "${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"/../../scripts/workpad.py. It is stateless, so nothing needs to survive between Bash calls.

Workpad-invocation ladder. workpad.py starts no shell and runs no .sh file (host needs: Python 3.11 or newer, an authenticated gh, and scripts/section_parse.py beside it). Rungs, advanced only when a rung fails: (1) the vendored path directly (.prflow/vendor/prflow/scripts/workpad.py …); (2) the file directly through the portable anchor form; (3) local/interactive tier only — python3 against the vendored path, then the anchor-resolved path; the cloud matcher refuses any interpreter-leading command. A rung has failed only when the run observed no invocation at all; a writing subcommand changes the comment before it returns, so before advancing a rung on a write, re-read the workpad and skip the retry when the write already landed — a second completion-evidence marker makes the finishing gate refuse the run. A run that exhausts its tier's rungs stops at Blocked without hand-writing a status (itself a workpad write through the program it failed to reach) — except the Terminal-status self-check's own status read, which records the status unestablished and continues — recording the skip, the program and each rung tried on the workpad when reachable, else in the PR description, else reported unrecordable.

For the helper's full subcommand and flag surface, emit .prflow/vendor/prflow/scripts/workpad.py --help and .prflow/vendor/prflow/scripts/workpad.py update --help. If neither prints help, do not improvise flags: use only the complete invocations the phase files carry, and record the unresolved reference with a --note.

Reflection style contract (every --reflection / --reflection-file bullet). A non-empty reflections[] trips the weekly retrospective's cheap gate and forces an LLM analysis, so every bullet must earn its place. Prose rules live in the shared writing standard, read at the reflection compose points in the phase files ("${CLAUDE_SKILL_DIR:-<absolute skill base directory this runner reports in context>}"/../../lib/writing-standard.md); a failed load emits a breadcrumb naming the file and failure kind, and the reflection is composed without it. Kind routing: friction/deviation you worked around → note; an engine/process-improvement proposal → improvement; the driving issue's claims were wrong or underspecified → issue-accuracy; a hard stop → blocked; punted work already tracked by a scope-decision-deferred record → deferred; untracked punted work, and failed-and-continued → dropped-failed. A clean confirmation — an assumption that held with no friction — is not a reflection, and writes no workpad row unless its own step names one.

Version-control wording (every inline --note / --reflection text the run writes). Describe a version-control step — a search, a checkout, a fetch, a comparison — by what it did, without the words git or diff ("regex search over the whole tree, untracked files included", "compared the branch with its base"): a worktree-isolated local session can refuse a plain workpad call whose text names them. Text that must keep the word verbatim, such as a search pattern or a quoted criterion, is exempt, and takes the file recipe below when it carries the characters that recipe names.

Interpolation-safe note and reflection text (file-based recipe, every tier). --note TEXT and --reflection TEXT traverse bash quoting, so text with backticks, $, double quotes or backslashes — often a search pattern a note names — can be mangled before the helper sees it. For such text, author the payload to a .prflow/tmp/ file with the Write tool, pass it as workpad.py update $ISSUE_NUMBER --reflection-kind improvement --reflection-file <run-scratch>/refl-$ISSUE_NUMBER.md (a note: --note-file <run-scratch>/note-$ISSUE_NUMBER.md; <run-scratch> is §1.1's per-arm scratch home, flat on the not-ignored arm), and delete the payload file after the helper call succeeds (rm <run-scratch>/refl-$ISSUE_NUMBER.md, or the note's file) — an adopter with no ignore rule for .prflow/tmp/ would otherwise trip Phase 4.3's clean-tree backstop. A terminal-status call never carries --reflection-file or --note-file: on a stop path the --status Blocked flip is its own update call, recorded first, and the file-based reflection or note follows separately — falling back to inline text on a structural error — so a bad payload can never cost the run its terminal status. Not a heredoc or >-redirect: the cloud matcher denies those shapes even with a granted head.

Failure-isolation contract (volatile vs. structural). Structural failures abort the whole call with no PATCH (exit 1, clear stderr): gh can't resolve the repo, the API call fails, a target section (## Progress/## Plan/## Acceptance Criteria) or the Last updated line is absent (or the Status line, for a --status mutation), a --rewrite-ac substring matches zero or multiple rows, a --rewrite-ac pair appends the (post-merge) tag (NEW ends with it; neither OLD nor the row it targets already does) without a non-empty --note rationale, a --replace-*-file/--set-reproduction-file is unreadable, or a --reflection-file payload is unreadable, non-UTF-8, or empty. A tick whose target row is already ticked is satisfied, whichever call ticked it. Volatile per-row tick misses are isolated, not aborted: a --tick-*/--tick-*-n flag that resolves to no row or ambiguously inside a present section (no match, several unticked matches, several ticked and no unticked matches, or an out-of-range index) does not discard the call — every other mutation is applied and PATCHed, and the call then exits non-zero naming each tick that did not land. The replay carve-out: a call whose only mutations are satisfied ticks returns outcome=replay remedy=none and makes no PATCH; a tick that lands now, an unresolved row, or any other mutation alongside stays on the ordinary path.

One moment, one call. Issue every workpad mutation belonging to one moment as a single update — repeatable flags repeated, independent flags combined, one PATCH — never one call per sub-step. Reconcile-row repairs apply before ticks, so a combined call is order-correct. Never dispatch these calls concurrently: an update fetches, mutates in memory and PATCHes the whole body back, and the --expect-* preconditions are checked against the fetched body, not at PATCH time, so concurrent calls lose writes. Four limits:

• A structural-abort flag carries only passengers one re-send restores. The --expect-* guards, --replace-acs-file, --rewrite-ac's zero/multiple-match refusal, every --record-*/--checkpoint operand-arity check, and an absent Last updated line or ## Progress section abort before any PATCH (the --tick-* family's row misses ride the PATCH through instead); outcome=not-persisted remedy=reissue-call re-sends the whole call, so what was folded in comes back. Three cases take no passengers: --expect-comment-id/--expect-status, whose remedy=re-resolve-state forbids a re-send (so the Phase 1.3 hydration call — --replace-acs-file plus its --expect-* guards — stays apart from progress writes); an abort whose cause must be repaired first, such as an unreadable or empty --reflection-file payload (Phase 3's soft-proceed splits its call for this); and any landed-* outcome, whose follow-up call carries only the corrective mutation.
• A second --reflection-kind — one kind per call, so two kinds need two calls.
• Anything across a phase2-durability-checkpoint.sh boundary — merging past one widens the work-loss window; for Phase 2's accruable population the boundary is itself the delivering moment (phase-2-implement.md §2.0.5).
• A staged decision point, where the next call's content depends on the previous call's outcome — two moments, not one.

Read the outcome line — it is the single signal. An update that reaches its exit path closes with the stderr line workpad.py update: outcome=<token> remedy=<token>; a crash bypasses it and emits none. Act on the named remedy; never infer the outcome from the prose lines above it.

No remedy re-sends a call whose PATCH landed — reissue-call pairs only with not-persisted; the corrective remedies each direct a follow-up call carrying only the corrective mutation, because re-sending a landed call double-writes the append-only notes. On re-resolve-state never re-send: live state changed, and a blind retry overwrites it.

An absent outcome line means the write did NOT land: a harness refusal or a crash emits nothing, so treat a missing line as unverified — never as landed — and re-resolve the live workpad before advancing.

Callers MUST read that line on any tick call — never advance on the stdout body alone, because a volatile miss PATCHes the body without landing its target tick; the echoed body is the row inventory to re-resolve a shifted index against. On retick-named-rows or retick-and-reset-status, re-resolve each named target (checkbox positions shift after a Phase 2.2.5 --replace-acs-file) and re-tick the named rows — do not blindly re-send the whole call, whose notes already landed — or, if a target cannot be resolved, route to the relevant Blocked path (the Phase 3.4 gate's step 4, or Phase 4.3's clean-tree/publish handling). The gate's pass condition is evidence-based: the targeted row is - [x] and the call reported remedy=none or remedy=reset-status (Status and ticks are independent); a satisfied tick's outcome=replay remedy=none is successful evidence too. This binds the Phase 3.4 AC gate, the Phase 4.3 --tick-progress "PR marked ready" finalize, and ordinary per-phase ticks.

--tick-plan/--tick-ac substring matching prefers a unique unticked ([ ]) row and accepts a unique already-ticked one as satisfied, so a duplicate tick is a no-op; --tick-plan-n/--tick-ac-n address by 1-based position within their own section, counting every [ ] and [x] row in ## Plan or ## Acceptance Criteria respectively — a whole-document count ticks the wrong row silently.

Resume the canonical workpad; never intentionally create another. Phase 1.3 performs the marker lookup before create; subsequent mutations go through update. Recover a lost $ISSUE_NUMBER mid-run per Context recovery below. On a re-run, intake reconciles the workpad's Progress/Reflections against corrective evidence, treating no review as complete, and hands off sourced decisions, corrections and blockers; outside intake, recover durable state directly. A prior Blocked status is a finished earlier run's history: intake records its cause, classifies the run terminal-re-trigger, and proceeds past Phase 1, re-raising Blocked only if the owning step still finds the cause live.

Always verify a Status PATCH actually landed. gh api -X PATCH can return success with the body unchanged, so an exit code cannot discharge this — the outcome line is the verification (the helper reads the Status back). Before advancing to the next phase, confirm outcome=landed or outcome=replay (remedy=none); any other token names its remedy above, and an absent line is unverified. Plan/Notes-only updates need no check.

Phase 1: Setup

Orientation only (the phase file is authoritative): run intake, branch setup and issue-claim audit serially in the shared checkout; each worker loads its own procedure and returns an artifact-backed handoff. Keep worker procedures and transcripts out of this context; retain terminal decisions and exact requirement artifacts.

Phase 2: Discover, Plan & Implement

Orientation only: explore the codebase; reproduce first when the recorded classification is bug-report; write the plan (the architect only for an open design decision); implement against the plan under the mandatory code sweeps; test; commit.

Phase 3: Review & Fix

Orientation only: open the draft PR; run the review-and-fix loop; enforce the acceptance-criteria gate before advancing.

Phase 4: Documentation

Orientation only: dispatch the finalization worker for follow-ups, documentation, PR description and final-tree gates; validate its compact evidence-backed result, then publish or leave a draft per config and finalize the workpad.

Completion Checklist

Before reporting completion, verify ALL phases executed:

• Phase 1: issue fetched; workpad created before the branch with run link, ## Progress checklist and mirrored Acceptance Criteria; branch exists and the workpad Branch line filled; Setup ticked
• Phase 2: reproduction signal recorded when the recorded classification is bug-report (Phase 1.3's classification: note, not the bug label); for a multi-PR issue the 2.2.5 scope-adjustment applied and ## Acceptance Criteria holds only in-scope items; the 2.3.0 changed-contract, 2.3.4 boundary-assumption, 2.3.4a self-authored-claim and 2.3.4b coverage-claim sweeps all ran over the §2.3 branch-delta operand (merge base → working tree, not just the uncommitted diff); code committed and pushed
• Phase 3: draft PR created; /prflow:review-and-fix ran; acceptance-criteria gate passed (PR still draft)
• Phase 4: follow-up issue(s) filed in 4.0 for 2.2.5-deferred criteria and in 4.0.5 (manifest hydrated) for a review-and-fix deferrals manifest; docs updated and the Documented label applied; PR description generated via /pr-description; working tree asserted clean (4.3 backstop, publish and draft cases alike) and any remainder committed; PR published via gh pr ready unless prflow_implement.implement_pr_state is draft (then left as the Phase 3.1 draft, no extra PR-thread comment); every applicable ## Progress item ticked; workpad finalized with Status: Complete (🎉, draft-aware --note wording) and the 🎉 outcome reaction emitted

If a phase was skipped or a Status PATCH didn't land, go back and complete it now. Do not stop after the PR is created or review approves — the PR stays a draft until Phase 4.3 publishes it (or deliberately leaves it a draft after finalizing workpad and reaction). Do not stop because acceptance criteria are unchecked on a multi-PR issue — apply the 2.2.5 scope-adjustment, then re-run the gate; Phase 3.4's Blocked stop is only for genuinely-failing in-scope criteria.

Terminal-status self-check (every turn boundary)

Once the workpad exists, read its live Status line — from the live comment, never from memory — before you end any turn; skip it and the run parks at an in-progress Status with nothing to restart it. Before §1.3 creates the workpad the grounds below alone govern. After §1.3, exit 2 (no workpad comment) means the workpad or its marker is gone: take §1.3's disappeared-workpad arm — stop with a diagnostic naming the failed status read and create no second workpad. Exit 1 (Status line missing or unrecognized) and exit 3 (gh transport or auth failure) are neither terminal nor a ground to end the turn: record the status unestablished and continue, as for a refused read.

Where the injected engine-ground-truth block is present, ending a turn ends the process, so no non-final ground below is usable there; the grounds govern the local/interactive tier only. The status read binds on every tier.

A turn may end only on:

• a harness refusal you cannot proceed past;
• a workpad Status that scripts/workpad.py status classes terminal — complete (🎉), blocked (👎), failed (💥) or cancelled (🛑) — though one read at the start of a resuming run is a finished earlier run's status and a resume trigger, not a ground, on either tier;
• the work driven to completion, the live Status terminal, and this turn carrying the run's final message.

Ending a turn on anything else — to report progress, request an uncalled-for confirmation, hand off, or at a "natural break" — is forbidden. An in-progress Status (🚀) means the run is unfinished: return to the phase that owns the remaining work and drive Status terminal. The commonest trip is stopping at "documentation done" when Phase 4.2 (/pr-description) and Phase 4.3 (finalize → Status: Complete 🎉 + outcome reaction) remain.

A refused status read is retried through the Workpad-invocation ladder; on a second refusal record the status unestablished and continue — a refused read is never a ground to end the turn. Only when the ladder is exhausted for writes too (no terminal Status reachable), or the status stays unestablished after it is exhausted for reads, end the turn on the harness-refusal ground, naming the refusal and each rung attempted, and report Blocked to your caller.

The check keys on the workpad Status, not PR draft state — a run finishing with a draft PR (implement_pr_state=draft) still reaches Status: Complete. On the cloud tier the devflow-implement.yml Stall backstop detects an interim Status post-run and re-dispatches (bounded auto-resume, honest-red on cap exhaustion) or, on a fail-loud exit, flips the workpad to Failed (💥) — it never drives a run to Complete; the local tier has no backstop.

Error Handling

• Empty steps: a phase producing no file changes skips the commit and continues — no empty commit.
• Git conflicts: on a push rejected for conflicts, run git pull --rebase origin {branch} and retry once; a second failure stops and reports. After any successful rebase, re-run the Phase 2.3.0 changed-contract sweep against the newly-arrived sites — a clean textual rebase can still surface a base-branch fixture, call site, or assertion the change's contract now rejects.
• Subagent failures: a subagent that fails or returns nothing useful is recorded via --reflection-kind dropped-failed --reflection "…" and the run continues; never retry the same subagent more than once.
• Permission denials: a denial refuses the form, not the work — re-form per phase-3-fix-loop.md's ladder, never the denied effect via a tool, interpreter, checkout, or self-attested check. Ladder spent: dropped-failed reflection naming helper, tier, remedy (local ~/.claude/settings.json; cloud install.sh --apply/allowed_tools token) and the absent artifact; workpad.py refused: PR body; no workpad/PR: name the terminal, unrecordable. A phase's own refusal arm stands. A denied verification is unestablished, not passed; never skip a phase over one.
• Commit prefixes: follow the project's declared commit-message convention; absent one, docs: for documentation, feat: for implementation, fix: for review and test fixes.
• Context recovery: recover the issue from $ARGUMENTS, branch/PR with git/gh, lifecycle with workpad.py status, and setup only from validated compact handoffs (phase2_resume, AC/audit paths, branch-setup record). Missing, stale, unreadable or evicted state: rerun the worker that owns it. Never read the full workpad, transcript, or setup procedure, or inline setup; later phases reread only their set and named shared refs.
• Surfacing failures: everything you "note and continue" on above goes to PRFlow Reflections via --reflection/--reflection-file, kind chosen by the Reflection style contract; no separate end-of-run comment is needed.