Arch Epic

arch-epic

After explicit selection, wraps $arch-step to execute a multi-plan goal. Filing or decomposing GitHub issues does not select this lifecycle. The skill takes a prose goal, proposes a plain-English decomposition whose count follows proof gates rather than a preset range, gets user approval, and then drives each sub-plan through arch-step's new → auto-plan → implement-loop → audit-implementation arc. After each sub-plan completes, a new clean critic child inspects the shipped work for scope drift against the approved North Star. If the critic finds missing authorized work, post-approval proposed expansion, or unauthorized built scope, the skill halts. It may resume ordinary missing work, but it never enlarges scope from the critic. A human decides whether to approve expansion and re-approve, or keep the boundary and require subtraction/redesign. Otherwise it advances to the next sub-plan.

The normal lane is interactive and re-entrant: arch-epic invokes or observes arch-step commands in the visible session one transition at a time.

The same-session automatic commands are explicit and opt-in: auto-plan is a strict sequential driver over real $arch-step auto-plan <SUBPLAN_DOC_PATH> runs. It handles one approved sub-plan at a time, requires the generated ArcStep receipt gate to report ready for that exact DOC_PATH, and only then marks the sub-plan planned before moving to the next one. auto-implement is a strict sequential driver over real $arch-step auto-implement <SUBPLAN_DOC_PATH> runs. It handles one planned sub-plan at a time, lets ArcStep own the full implement/prove/audit loop, runs the epic critic only after ArcStep's implementation audit says Verdict (code): COMPLETE, and marks the sub-plan complete only after that critic passes.

Role-based automatic execution is transport-aware. After decomposition approval, arch-epic drives epic_planner, implementation_worker, and critic roles from durable epic/sub-plan artifacts. Same-host roles normally start as clean native children. The external-harness lane remains explicit and opt-in when a different provider, load-bearing exact model/profile, durable or detached lifecycle, worktree/process isolation, automation surface, structured receipt, or another real benefit is worth the added process cost. In that lane the existing script resolves and pins the external role table and owns only invocation and receipt mechanics. Workers apply arch-step doctrine directly from disk; they do not invoke nested auto-plan, implement-loop, or other automatic continuation commands.

Planner and implementation worker roles are resumable regardless of transport. If a new clean critic finds in-scope unfinished work, arch-epic resumes the exact planner or implementation worker with the critic's observation and artifact evidence. The critic never prescribes repair steps, and ordinary repair does not start a separate repair-worker role.

Progressive lazy planning is the default for interactive and role-based work: sub-plan N+1 is not planned until sub-plan N is complete. Same-session auto-plan is the deliberate exception: it plans all approved sub-plans first, but still plans exactly one sub-plan at a time and stops before implementation. The user approves the decomposition up front, then approves each sub-plan's North Star when it comes up in interactive mode. In role-based automatic mode, new clean critics check North Star and Epic Requirement Coverage gates instead of asking the user on every sub-plan.

Resume is the only mode — every $arch-epic invocation re-reads the epic doc and sub-plan docs from disk and picks up where things left off. "Continue my epic", "pick up where we left off", "keep going on " all work.

The skill is a thoughtful wrapper — its job is to reduce user orchestration burden. In interactive mode, user involvement is bounded to the goal, decomposition, per-sub-plan North Star, and material scope-preservation decisions. In role-based automatic mode, the user approves the decomposition up front; an external harness also pins its role table. Clean critics replace per-sub-plan North-Star pauses unless a material ambiguity or scope change requires the user.

When to use

• "This is too big for one arch-step plan. Help me break it into plans and run them in order."
• "Orchestrate these sub-plans: X, Y, Z. Check each one before moving to the next."
• "Continue my epic at docs/EPIC_<slug>_<date>.md."
• "Keep going on the epic."
• "Pick up where we left off on ."
• "Automatically implement this approved epic end to end."
• "Auto-plan every sub-plan before we implement any of them."
• "Run arch-epic auto-implement on this approved epic."
• "Run the epic automatically and ask me which models to use for the planner, implementation worker, and critics."

When not to use

• Single architecture plan, including single-plan automatic planning through implementation: use $arch-step full-auto or $miniarch-step full-auto.
• One-pass mini plan that hands off to implement: use $arch-mini-plan.
• 1–3 phase feature flow: use $lilarch.
• Open-ended optimization with bet-and-learn iteration: use native goal mode.
• Read-only routing across arch artifacts: use $arch-flow.
• Stepped orchestration in a foreign repo with a per-step critic: use $stepwise.
• One-shot review of a diff, branch, or completion claim: use ordinary host review. Use $codex-review-yolo only when the exact external yolo profile and its receipts are the requested benefit.
• Work that fits in a single orchestrator turn.

Non-negotiables

Must happen every run:

• Pin raw_goal verbatim with sha256 in the epic doc. Any silent rewrite clears the decomposition-approved flag.
• Produce a one-sentence-per-sub-plan decomposition and get user approval before planning any sub-plan.
• Treat the raw human goal and approved decomposition as the epic baseline. Decomposition approval does not authorize hidden infrastructure in later sub-plans. Apply ../_shared/scope-and-convergence.md.
• Apply ../_shared/agent-orchestration-policy.md whenever a planner, worker, or critic is dispatched, and apply $prompt-authoring to every actual populated first brief or materially reframed follow-up. Prefer a clean native child for ordinary same-host work. Use the explicit external harness when a concrete provider, exact model/profile, durable or detached lifecycle, worktree/process isolation, automation surface, structured receipt, or another real benefit is worth the added process and integration cost. These examples are recognition aids, not an allowlist.
• Native starting context is explicit. Codex dispatch always sets fork_turns to "none" for clean planner/worker/critic roles, to a positive count only for deliberately bounded chat context, or to "all" only when the full conversation is genuinely required. Claude uses a clean named subagent by default; an explicit conversation fork means full inherited conversation, while a skill with context: fork is an isolated clean subagent context. Context is separate from permissions, capabilities, and worktree isolation.
• The parent owns sequencing, external topology, and final integration. Planner, worker, and critic prompts allow each role its own native sub-agents on its own host and forbid starting external agents.
• Each sub-plan inherits its approved epic boundary, records its own initial minimal convergence closure during initial architecture, and signs off that closure before implementation. After sign-off, only explicit human approval may add a path, obligation, sub-plan, mechanism, or proof category.
• Each sub-plan is its own full $arch-step canonical DOC_PATH. The epic doc does NOT contain plan internals (no Sections 0–10, no call-site audit).
• Progressive planning: in interactive and role-based automatic modes, invoke $arch-step new or planner harness work for sub-plan N+1 only after sub-plan N is complete per the epic critic. In same-session auto-plan, assign or create only the scaffold needed for the next sub-plan's canonical DOC_PATH, then invoke or continue the real $arch-step auto-plan <SUBPLAN_DOC_PATH> flow for that exact DOC_PATH. Creation, scaffold repair, copied sections, or marker-looking text are never readiness proof.
• In same-session auto-plan, update a sub-plan Status to planned only after python3 skills/arch-step/scripts/arch_stage_gate.py ready --doc <SUBPLAN_DOC_PATH> exits 0 for that exact DOC_PATH. If the gate is not ready, keep or set the sub-plan to planning and continue or report the exact $arch-step auto-plan <SUBPLAN_DOC_PATH> command.
• Per-sub-plan North Star approval uses $arch-step's existing North-Star gate. arch-epic does not re-invent it — it just stops when arch-step stops. In role-based automatic mode, this gate is replaced by a new clean North-Star critic after the user-approved decomposition is pinned. An external harness also pins its role table. In same-session auto-plan, the approved decomposition can stand in for per-sub-plan user approval only when the sub-plan North Star is a direct, unambiguous expansion of the approved epic scope; otherwise stop and ask.
• Per-sub-plan implementation runs through $arch-step implement-loop in interactive mode and real $arch-step auto-implement <SUBPLAN_DOC_PATH> in same-session auto-implement. Same-session auto-implement is not complete after one invocation; it keeps the selected sub-plan at implementing and continues the ArcStep implement/prove/audit loop until arch_skill:block:implementation_audit says Verdict (code): COMPLETE or a true blocker stops progress. In role-based automatic mode, implementation workers execute the approved sub-plan directly from arch-step doctrine and the sub-plan doc; the top-level orchestrator still does not edit target code itself.
• Epic critic runs once per sub-plan at sub-plan completion and returns structured JSON EpicVerdict. It is always a new clean child and is never resumed. Prefer native dispatch; the external harness remains available for deliberate external benefits.
• Permissions and worktree posture are resolved independently from starting context. Use enforced read-only capability for critics when available, retain the no-edit prompt contract, and compare repository state before and after critic work. External harness processes keep the existing dangerous / skip-permissions / no-sandbox convention; that convention does not describe native children.
• Native role execution needs no invented runtime/model promise. For the explicit external harness, the user supplies role execution for epic_planner, implementation_worker, and critic; ask once for missing load-bearing values. An omitted model on an external Codex role defaults to gpt-6-astra, and an omitted effort on that Astra role defaults to xhigh. An external Kimi role defaults to kimi-code/k3 and the model-default max effort; other runtimes, Codex models, and efforts never silently default. Natural Grok wording resolves to grok-4.6, while explicitly named legacy Grok ids remain exact. Existing external policies with legacy repair_worker values may load, but ordinary critic failures resume the exact original planner or implementation worker. Same-session auto-plan needs no role table. Same-session auto-implement uses the same transport-selected completion-critic policy as interactive mode.
• Resume is re-entrant: any invocation against an existing epic doc re-reads on-disk state and continues. No dedicated resume command.

Must never happen:

• arch-epic editing the target repo's code directly. Sub-plans do that via arch-step's implement-loop in interactive mode or implementation workers in role-based automatic mode.
• Scope reduction. The epic scope is the epic scope. If the critic sees a dropped, narrowed, or silently removed requirement from the raw goal, approved Decomposition, North Star, Epic Requirement Coverage, Section 7, acceptance criteria, or verification obligations, the sub-plan fails. A requirement assigned to a named later sub-plan is preserved scope, not a failure for the current sub-plan. Agent-written Decision Log entries are evidence, not approval to reduce scope.
• Scope expansion by an agent, critic, review, or Decision Log. The same symmetry applies to additions: initial sub-plan architecture may record the smallest evidenced same-contract closure before sign-off; any later addition or new sub-plan needs explicit human approval. A Decision Log entry proves a change was recorded, not that it was authorized.
• Auto-acting on materially-different-path detections without user approval. Material scope discoveries always halt. The human may approve expansion via extend_current or new_sub_plan, or keep the approved boundary and require subtraction/redesign. No critic recommendation is self-authorizing.
• Letting critics author repair steps. Critics report verdict, failed checks, evidence, and scope discoveries only. The parent routes the result, and the resumed planner or implementation worker owns the reasoning for the next attempt.
• Starting a separate repair worker for ordinary in-scope critic failures. Exact-role resume is the default repair path; a new clean role child is only for unrecoverable handle loss, invalidated inputs, or explicit user override.
• Parallel planning or parallel implementation. Same-session auto-plan may plan every sub-plan before implementation, but it still handles one sub-plan at a time in decomposition order. Implementation always runs one sub-plan at a time and advances only after the epic critic passes.
• Marking a same-session auto-plan sub-plan planned from a consistency marker, plausible Section 3-7 content, prior stored status, or ArcEpic-authored setup. The ArcStep generated receipt gate is the proof.
• Same-session auto-implement starting while any non-complete sub-plan is not planned. Plan all sub-plans first with auto-plan.
• Marking a same-session auto-implement sub-plan complete from stored Status, worklog optimism, local proof, one $arch-step auto-implement invocation, or ArcStep audit alone. ArcStep audit COMPLETE must come first, then the epic critic must return pass.
• Running the epic critic while the sub-plan implementation audit is missing, NOT COMPLETE, reopened, or otherwise not clean. Continue or report $arch-step auto-implement <SUBPLAN_DOC_PATH> for that sub-plan instead.
• Two-second child polling. The external-harness lane defaults to 180-second waits while waiting for external processes unless the user explicitly pins a different cadence in the role policy.
• Calling a slow planner or worker "hung" just because it has no final artifact after a few minutes. Native host state or external stream receipts may show progress; external children often run for 5+ minutes; broad xhigh or max planner/worker runs can reasonably take 20-40 minutes. In the external lane use process state plus events.jsonl, stderr.log, stream.log, heartbeat.json, and monitor.json; treat recent thinking/tool/output stream activity as progress.
• Terminating an external child before the long-run floors expire unless there is clear failure evidence. External defaults are: poll every 180s, call a run quiet only after 900s without stream activity, and call it needs_attention only after 1800s without stream activity or after the pinned max runtime.
• Passing raw model shorthand to external subprocesses. Resolve it first using shared model-resolution doctrine; preserve exact family/version or ask for the runnable ID.
• Heuristic keyword mapping for decomposition. Interpretation is prose reasoning, taught by references/decomposition-principles.md.
• A second "resume" command. The user types what they type; the skill figures it out from the epic doc + sub-plan docs.

First move

1. Capture the user's goal verbatim. Compute sha256.
2. Resolve or propose the epic doc path (docs/EPIC_<TITLE>_<YYYY-MM-DD>.md).
3. Read ../_shared/agent-orchestration-policy.md and references/model-and-effort.md. Prefer clean native same-host roles. Ask one consolidated question only when an explicit external harness or another selected external lane lacks load-bearing execution values. Same-session auto-plan runs no critic during planning.
4. Read references/decomposition-principles.md. Draft the Decomposition (one-sentence descriptions, assertion-style gates, dependency-then-risk ordering, and count chosen from real proof boundaries rather than a target range).
5. Read ../_shared/scope-and-convergence.md.
6. Read references/epic-doc-contract.md. Write the epic doc.
7. Surface the Decomposition and ask the user to approve or adjust.

Modes (re-entrant; one per turn)

Detail per mode lives in references/workflow-contract.md.

1. start — epic doc does not yet exist. Propose the path, resolve the intended lane without inventing native model settings, ask only for missing external values when an external lane was selected, draft the Decomposition, and surface it for approval.
2. approve-decomposition — epic doc has sub_plans_approved: false. Apply user adjustments, flip flag, set status: active.
3. run — main orchestration pass. Routes per references/arch-step-integration.md to the next arch-step command for the first non-complete sub-plan or runs the critic.
4. resume-scope-change — epic is halted after a critic flagged a scope issue; a human has replied. Apply the explicit choice: approve and re-approve an extend_current/new_sub_plan expansion, or keep scope and route subtraction/redesign. Log the human decision and resume.
5. summary — user asked a status question. Render a table of sub-plan statuses and the most recent log entries. No state changes.
6. auto-plan — same-session planning driver after decomposition approval. Sets up the next sub-plan DOC_PATH, drives real $arch-step auto-plan <SUBPLAN_DOC_PATH> for that exact doc, runs the ArcStep readiness gate, marks it planned only when the gate exits 0, then repeats for the next sub-plan in decomposition order. It stops before implementation.
7. auto-implement — same-session implementation driver. Requires every non-complete sub-plan to be planned, then runs each in order through real $arch-step auto-implement <SUBPLAN_DOC_PATH> until ArcStep audit is COMPLETE, runs the epic critic, and marks the sub-plan complete only after critic pass.
8. auto-run — role-based automatic execution after decomposition approval. Prefer clean native planner/worker/critic children from durable artifacts, resume the exact planner or worker for repair, and start every critic clean. If the external harness was deliberately selected, resolve and pin its role table, initialize its auto run directory, and use the script only for external invocation and receipts.

Output expectations

• Epic doc at the user-named (or proposed) path.
• Per-sub-plan canonical arch-step DOC_PATHs under docs/epic/<EPIC_SLUG_WITH_DATE>/PHASE_<NN>_<SUBPLAN_SLUG>_<YYYY-MM-DD>.md, owned by arch-step.
• Same-session auto-plan leaves non-complete sub-plans at Status planned only when their exact DOC_PATH passes the arch-step generated receipt gate.
• Native role dispatches record their exact child handles and return evidence as compact Orchestration Log pointers. External epic critic artifacts live under <orchestrator repo root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/ including the EpicVerdict JSON, the exact invocation.sh, and the subprocess stream log.
• External-harness automatic artifacts live under <orchestrator repo root>/.arch_skill/arch-epic/auto/<epic-slug>/run-<ts>/ including state.json, execution_policy.json, worker prompts, worker session IDs, latest worker-attempt pointers, critic verdicts, child events.jsonl, stderr.log, stream.log, heartbeat.json, monitor.json, and report.md.
• Orchestration Log and Decision Log append-only in the epic doc.
• Console summary with the epic doc path, the per-sub-plan status table, and the current active sub-plan's next action.

Reference map

• references/workflow-contract.md — re-entrant modes with inputs, outputs, failure modes, judgment-vs-determinism split.
• references/epic-doc-contract.md — epic doc shape, frontmatter, section structure, mutation rules, validation on load.
• references/decomposition-principles.md — when to split a goal into sub-plans. Prose reasoning with worked examples; no keyword tables.
• ../_shared/depth-first-planning.md — destination map, first working slice, expansion map, proof gates, and scope-cut distinction shared with arch-step and miniarch-step.
• references/arch-step-integration.md — sub-plan Status → arch-step command mapping. What the skill invokes vs. what the user or native goal-mode continuation does.
• references/scope-change-discipline.md — approved scope lock, materially-different path vs noise, and preservation-only scope decisions.
• references/critic-contract.md — EpicVerdict JSON schema and scope-drift / requirement-coverage checks.
• references/critic-prompt.md — verbatim critic prompt body with placeholders.
• references/auto-harness-prompts.md — transport-neutral role prompt contracts for planner, implementation, exact-role continuation, and clean critics.
• references/epic-verdict-schema.json — JSON schema file used by Codex --output-schema, inlined into Claude --json-schema, and appended to Grok and Kimi critic prompts before post-validation.
• references/model-and-effort.md — native-first role dispatch plus external model shorthand resolution, exact-version preservation, and ask-once discipline.
• references/resume-semantics.md — how the skill re-derives state each turn from the epic doc + sub-plan docs.
• references/examples.md — worked examples: happy path, scope-change insertion, harmless observations ignored.

The external harness adapter

scripts/run_arch_epic.py is deterministic external-lane plumbing. After the orchestrator deliberately selects the external harness, it resolves the external role policy, creates run directories, spawns and resumes workers, spawns structured critics, and writes artifacts. It does NOT choose transport, interpret decomposition, draft the epic doc, decide verdicts, or route sub-plan states — those live in the orchestrator's prose reasoning.

python3 scripts/run_arch_epic.py critic-spawn \
  --epic-doc <path> \
  --sub-plan-name "<name>" \
  --sub-plan-doc-path <path> \
  --prompt-file <path> \
  --schema-file references/epic-verdict-schema.json \
  --runtime claude|codex|grok|kimi \
  --model <model> \
  --effort <effort> \
  [--codex-profile <profile>] \
  [--orchestrator-root <dir>]

External-harness examples:

python3 scripts/run_arch_epic.py resolve-execution \
  --policy-file /tmp/arch-epic-auto-policy.json

python3 scripts/run_arch_epic.py auto-init \
  --epic-doc docs/EPIC_BIG_GOAL_2026-04-26.md \
  --policy-file /tmp/arch-epic-auto-policy.json

python3 scripts/run_arch_epic.py worker-spawn \
  --run-dir .arch_skill/arch-epic/auto/big-goal/run-2026-04-26T00-00-00Z \
  --target-repo . \
  --role implementation_worker \
  --sub-plan-name "Build the core service" \
  --prompt-file /tmp/worker.prompt.md \
  --run-mode auto

python3 scripts/run_arch_epic.py worker-resume \
  --run-dir .arch_skill/arch-epic/auto/big-goal/run-2026-04-26T00-00-00Z \
  --target-repo . \
  --role implementation_worker \
  --sub-plan-name "Build the core service" \
  --prompt-file /tmp/continue.prompt.md \
  --session-id <session-id-from-session_id.txt> \
  --try-k 2 \
  --run-mode auto

python3 scripts/run_arch_epic.py child-status \
  --try-dir <printed-child-run-dir> \
  --json

python3 scripts/run_arch_epic.py child-tail \
  --try-dir <printed-child-run-dir> \
  --lines 80

python3 scripts/run_arch_epic.py child-finalize \
  --try-dir <printed-child-run-dir>

Foreground child runs print the session ID or verdict path after completion. Detached child runs print the child run directory immediately; use child-status, child-tail, and child-finalize to monitor and finalize them. Writes:

• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/prompt.md
• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/invocation.sh
• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/stdout.final.json
• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/events.jsonl
• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/stderr.log
• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/stream.log
• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/heartbeat.json
• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/monitor.json
• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/verdict.json
• <orch-root>/.arch_skill/arch-epic/critics/<slug>/run-<ts>/start_ts / end_ts / exit_code