Epic Plan

Epic Plan Skill

Use this skill only from the root session. The root session must delegate the supplied objective to the project custom agent epic-planner; it must not execute this procedure locally or route it through orchestrator. The root-invocation hook records the authorization receipt consumed when epic-planner starts.

Use the objective or existing manifest path supplied in the invoking user request.

Planning ends after every child feature has completed promotion, research, feature documents, atomic planning, and preflight clearance. Atomic execution, PR authoring, feature execution review, and CI monitoring are not part of this skill.

Prerequisites

Before proceeding, epic-planner must read AGENTS.md, the applicable language policies under .agents/skills/, config/orchestration-routing.json, and any existing artifacts/orchestration/epic-planner-state.json checkpoint.

Epic-Worthiness Gate

The objective warrants an epic only when both conditions hold:

1. It decomposes into at least two independently mergeable child features, each with its own issue, active feature folder, and eventual PR.
2. At least one child exceeds, or the combined work clearly exceeds, one practical large-path feature budget.

When either condition fails, record epic_worthiness.verdict: "non_epic", state the feature-count and change-budget rationale, and offer a single root-session orchestrator delegation. Do not create epic scaffolding unless the user explicitly overrides the verdict.

Decomposition and Wave Design

For an epic-worthy objective:

1. Define docs/features/epics/<epic-slug>/ and author epic.md using the manifest schema in epic-orchestrate.
2. Record goal, scope, non-goals, shared design, acceptance criteria, decomposition rationale, production-file estimates, and integration risks.
3. Add depends_on edges only for real upstream contracts.
4. Compute execution waves with the longest-path formula in scripts/dev_tools/epic_wave_computation.py; unresolved references and cycles block preparation.
5. Assess each child as C1-C4 using the central policy. Record the assessed band, rationale, deployment agent, model, reasoning effort, and the monotonic orchestration complexity ceiling.
6. Set max_parallel_features to an integer from 1 through 8. Use the routing-policy default of 4 unless repository or user constraints require a lower value.

Child issue numbers may be placeholders only while the draft manifest is being decomposed. Before creating child worktrees, promote every child through the worktree-aware MCP lifecycle, backfill the final positive issue_num and active feature_folder, commit and push that resolved manifest, and persist the promotion receipts. Launch specifications and their immutable receipts must never use placeholders.

Integration Branch

Create or reuse epic/<epic-slug>-integration from origin/main, push it, and commit the epic home before preparation. All prepared child outputs must fan into this branch.

Concurrent Preparation

Place all child preparations in one preparation batch, regardless of execution-wave dependencies. Each child runs in an isolated worktree branched from the current origin/epic/<epic-slug>-integration tip. Dependency context is supplied for planning, but it does not serialize preparation. The batch launcher enforces max_parallel_features; excess children remain queued in the same batch rather than being divided by execution wave.

Before each child starts, persist its epic-child topology receipt, complexity assessment, delegation receipt, and Codex model-routing receipt. The model receipt must carry the same delegation_id as the delegation receipt.

Do not use native spawn_agent for a worktree child because that API does not bind the child to the prepared worktree. Write one immutable launch specification under artifacts/orchestration/epic-child-launches/<batch-id>/ and invoke .codex/scripts/launch-epic-child-wave.ps1. Use checkpoint_kind: "epic-planner", wave_number: 0, the planner checkpoint path, integration branch, bounded maximum, and one launch record per child. Every record supplies the unique launch/delegation ids, prepared worktree and branch, generated orchestrator-cN profile, exact model/reasoning/permissions, and prompt. C3 epic children use the elevated Sol/High profile. Monitor the returned durable status path; a nonzero child exit or missing completion status blocks fan-in.

The launch specification schema is:

{
  "schema_version": 1,
  "wave_id": "<safe-preparation-batch-id>",
  "checkpoint_kind": "epic-planner",
  "checkpoint_path": "artifacts/orchestration/epic-planner-state.json",
  "integration_branch": "epic/<epic-slug>-integration",
  "wave_number": 0,
  "max_parallel_features": 4,
  "launches": [
    {
      "launch_id": "<unique-id>",
      "delegation_id": "<unique-id>",
      "feature_folder": "<final-active-feature-folder>",
      "issue_num": 123,
      "deployment_agent": "orchestrator-c3-elevated",
      "model": "gpt-5.6-sol",
      "model_reasoning_effort": "high",
      "permissions": "orchestrator-workspace",
      "execution_context": "epic_preparation_child",
      "worktree_path": "<canonical-absolute-path>",
      "branch_name": "<child-preparation-branch>",
      "prompt": "<preparation prompt>"
    }
  ]
}

Write it under artifacts/orchestration/epic-child-launches/<batch-id>/, then run:

pwsh -NoProfile -File .codex/scripts/launch-epic-child-wave.ps1 -LaunchSpecPath <spec-path> -MaxParallel <max_parallel_features>

Parse the returned JSON and persist its shared status_path. Every worktree must be a clean Git worktree of this repository on the checkpoint branch. Its committed .codex/, .agents/, AGENTS.md, routing configuration, and selected profile must match the trusted integration source; the launcher rejects drift before starting Codex.

Every child prompt must contain this literal line:

Preparation mode: true. route_id: preparation. epic_feature_folder: <epic-slug>. integration_branch: epic/<epic-slug>-integration. Reuse and verify the completed promotion receipt, then perform research, feature documents (issue.md, spec.md, user-story.md), atomic planning, and preflight clearance only. Atomic execution, PR authoring, and CI monitoring are out of scope for this run and are executed later by epic-orchestrator. After the atomic-executor preflight returns PREFLIGHT: ALL CLEAR, commit the feature folder and plan to the current branch, set out-of-scope step statuses to not-applicable, set next_step to S5_atomic_execution, and stop, reporting research_path, plan-path, preflight_evidence_path, and the exact preflight status.

The line intentionally omits Epic mode: true. For dependent children, also cite the upstream manifest scope, specification, and planned contract.

Preparation Route Contract

Each child selects the exact preparation route from the central routing configuration:

• required agents, in configured order: task-researcher, prd-feature, atomic-planner, atomic-executor;
• required skills: orchestrate, feature-promotion-lifecycle, atomic-plan-contract;
• required MCP operations: new_potential_entry, potential_to_issue, new_active_feature_folder, validate_orchestration_artifacts;
• mandatory completed phases: S3_promotion, S4_atomic_planning;
• terminal next_step: S5_atomic_execution;
• execution-through-CI statuses: not-applicable;
• blocked_reason: none;
• requires_ci_gate: the literal JSON Boolean false.

Promotion must use worktree-aware MCP calls and receipts. A child must not claim feature completion, create a PR, execute the atomic plan, or monitor CI.

Fan-In

As each preparation finishes:

1. Merge the child preparation branch into the integration branch.
2. Treat any conflict as a decomposition defect: abort fan-in, record blocked state, and do not resolve the conflict ad hoc.
3. Backfill issue_num and feature_folder in epic.md.
4. Record preparation_status: "prepared", research_path, plan_path, preflight_evidence_path, and preflight_status: "PREFLIGHT: ALL CLEAR" in the planner checkpoint. research_path must be under docs/features/<feature>/research/ inside the feature folder. Each child references its immutable receipt and the shared wave.<wave_id>.status.json path.
5. Remove the worktree only after its preparation branch is merged.

Push the integration branch after final fan-in.

There is no mid-planning approval pause. The planner completes promotion, research, feature documents, atomic planning, and preflight before stopping at the user execution boundary.

Execution-Readiness Gate

Do not emit a kickoff until the manifest is valid, the checkpoint has a forced epic-planner topology receipt, and every child has a promoted issue, active folder, issue.md, research, spec.md, user-story.md, approved atomic plan, epic-preparation topology receipt, delegation-bound model-routing receipt, successful launcher receipt/status, PREFLIGHT: ALL CLEAR evidence, and a pushed preparation commit. The durable and ignored kickoff copies must be byte-identical; the manifest, durable kickoff, plans, and planning commits must pass the repository-aware readiness validator without worktree drift.

Invoke validate_orchestration_artifacts for epic-planner-state with require_ready_for_execution: true and the explicit workspace root. Do not write or delegate the kickoff until this canonical gate succeeds.

Kickoff Artifacts

Write the ignored copy to artifacts/orchestration/epic-kickoff-<epic-slug>.md and commit the durable copy at docs/features/epics/<epic-slug>/epic-kickoff.md:

# Epic Kickoff: <epic-slug>

Planned by epic-planner on <iso8601>. All child features are prepared. Planning state:
artifacts/orchestration/epic-planner-state.json (branch: epic/<epic-slug>-integration).

## Invocation Prompt

Run `/epic-run <epic-slug>` to execute this epic, or paste the prompt below.

Use the epic-orchestrator subagent to execute the prepared epic at
docs/features/epics/<epic-slug>/epic.md. Reuse epic/<epic-slug>-integration. Every child resumes
at atomic execution from its committed plan-path; do not repeat promotion, research, feature
documents, planning, or preflight.

## Feature Summary

| issue_num | feature_folder | wave | complexity | plan-path |
| --- | --- | --- | --- | --- |
| ... | ... | ... | ... | ... |

The baseline artifact shape is authoritative. An optional integrity block may record the planning commit and plan hashes, but epic-run must derive absent integrity values from Git.

Checkpoint and Completion

Persist artifacts/orchestration/epic-planner-state.json after every completed step with: objective, epic folder and manifest, integration branch, worthiness verdict and rationale, the bounded max_parallel_features, forced root topology_receipt, and kickoff path. Each feature records issue/folder/dependencies/wave/complexity, research_path, plan_path, optional preflight_evidence_path, preparation/preflight state, branch/worktree, topology receipt, delegation receipt, delegation-bound model receipt, launch receipt/status paths, and planning commit/hash when declared. Also record completed_steps, next_step, and last_updated.

The successful terminal result is EPIC_EXECUTION_READY. The final report lists the manifest, integration branch, both kickoff paths, and one plan-path: and preflight-status line per child. It must state that execution has not started and starts only after a later root invocation of epic-run.