claude-phase-roadmap-builder

Invoke the roadmap builder with an optional path to your markdown spec; it reads the conversation and spec, decomposes the work into aliased phases with a dependency DAG, and writes specs/phase-plans-v<N>.md. The output is validated with phase-loop validate-roadmap before handoff.

Run the Skill against the existing specs/phase-plans-v*.md file; it detects append mode automatically, continues phase numbering from the highest existing phase, and never edits prior phases. New aliases must not collide with the existing alias set.

It requires stable headings parsed by regex: phase headings in the form '### Phase N — <Name> (<ALIAS>)', field labels like **Objective** and **Exit criteria** on their own lines, bulleted Key files, and checkbox exit criteria with EC-<ALIAS>-<N> goal IDs. The roadmap-template.md reference defines the exact skeleton.

Skip it for single-phase or single-concern changes, which belong in a detailed plan instead, and for lane-level planning of one phase, which is claude-plan-phase's job. Pure research questions should go to an Explore agent directly.

The validator requires the exact form '### Phase N — <Name> (<ALIAS>)' with an alphanumeric alias and nothing after the closing parenthesis. A malformed heading is not parsed as a phase at all, which cascades into unknown-alias and DAG errors, so fix the heading first and re-run the validator.

Yes, pass --review-external to run Gemini and Codex CLIs in parallel against the written roadmap using the bundled review prompt. Results are written to a <output-path>_reviews.md sibling file, and both CLIs must be installed and authenticated.