Plan

plan

Produce a feature's architecture plan — Checkpoint 4, the most consequential architectural checkpoint. Where engineering authority over code design and performance is exercised: the agent proposes, the human decides.

Mixed mode — the agent proposes the architecture, the human confirms it, then the rest of the plan is drafted.

When to use

After discover-acs (Checkpoint 2) and atdd plugin atdd skill (Checkpoint 3). Produces plan.md.

If spec.md is missing, warn — planning should follow spec formalization — but the user may override and plan from acs.md alone (flag the skipped step in the handoff).

Not for: Given/When/Then specs (atdd plugin atdd skill); small changes to an existing plan (feature-edit).

Workflow

Step 0 — Entry gate. Before starting, verify the prior checkpoint is complete: run ${PLUGIN_ROOT}/scripts/dae_handoff.py <feature-dir> --through 3. On a non-zero exit, stop and surface the gap to the human — do not proceed.

Verify branch hygiene: run ${PLUGIN_ROOT}/scripts/dae_branch.py <feature-dir>. On a non-zero exit, stop and surface the message to the human — switch branches and re-invoke. The check honors the git.manual: true manifest opt-out.

After the gate passes, show the pipeline breadcrumb: run ${PLUGIN_ROOT}/scripts/dae_progress.py <feature-dir> and present its output to the human — it shows where this checkpoint sits in the DAE pipeline. The breadcrumb is advisory: a non-zero exit or a missing progress.md never blocks the skill. Then create one Codex plan item per workflow step below. See ${PLUGIN_ROOT}/references/progress-indicator.md.

1. Resolve + load — resolve the methodology root + manifest via ${PLUGIN_ROOT}/scripts/dae_resolve.py (see references/resolving.md); load feature.md, acs.md, spec.md, CHARTER.md.
2. Propose the architecture — draft only the Architecture section (components, data flow, where new code lives, coupling, key decisions + rationale + alternatives). Present it; iterate until the human confirms. Do not draft the rest until then.
3. Draft the rest — once confirmed, draft the remaining sections; the human reviews the finished file.
4. Charter Check — validate the plan against CHARTER.md. Produce the two-part structured check: a compliance table (one row per charter rule, plus auto-rows for autonomy stance, verification independence, mutation policy, and — at high autonomy — performance budgets), and an Amendments section. Hard rule: never finish a plan with a ⚠️ deviation that lacks a matching amendment ADR. Either write the amendment inline, or stop and emit a handoff with human_action_needed: decision.
5. Write plan.md — frontmatter (slug, checkpoint: 4, plan_status, created) + sections: Architecture, Charter Check, Phasing, Performance budgets, Collaboration schedule, Execution modes, Test strategy. Test strategy must explicitly incorporate feature.md's validation_method if it carries a non-default value — e.g. if validation_method is "canary 5% prod for 24h, watch dashboard X," the Test strategy section names the canary phase, the dashboard, and the rollback trigger. If validation_method is absent, default to the standard DAE stack (acceptance + unit + mutation per charter) and say so explicitly.
6. Handoff — emit a summary.

plan.md has phasing (stages/slices), not a task list — tasks emerge from specs (one spec = one TDD cycle), driven by atdd plugin atdd-team skill.

Handoff

Emit per ${PLUGIN_ROOT}/references/handoff-summary.md. checkpoint: 4; recommended_next: "atdd plugin -> atdd-team skill to implement against the specs". If a deviation needs a decision, human_action_needed: yes (decision).

The handoff MUST include the exit_criteria block asserting each of Checkpoint 4's exit criteria (Foundation Design Section 8) with verified_by, met, and evidence. For verified_by: tool criteria, the evidence MUST be the tool's actual output. The checkpoint is marked done only when every criterion is met.

References

• Foundation Design — the structured Charter Check (Section 3)
• The DAE methodology page — execution model, autonomy levels, collaboration schedule