Imported from Consiliency/agent-harness (skills-src/gemini/gemini-phase-roadmap-builder/SKILL.md). Install upstream with npx skills add Consiliency/agent-harness --skill gemini-phase-roadmap-builder. Copyright stays with the author.

Gemini Phase Roadmap Builder

Builds a multi-phase roadmap that downstream gemini-plan-phase can turn into implementation lanes. This is the Gemini port of the Claude-oriented roadmap builder; do not edit or depend on the original skill at runtime.

Shared Protocol

Follow shared/phase-loop/protocol.md for the shared closeout contract. Roadmap-builder closeout must emit automation: metadata that agrees with the human-readable Next phase, next_skill, next_command, and verification_status fields.

Core Rules

Use phase_loop_runtime.skill_paths resolver helpers for harness skill roots, handoff roots, helper roots, and reflection roots.

• Preserve Plan Mode boundaries. In Plan Mode, inspect files and produce a <proposed_plan> roadmap only; do not create or edit repo-tracked files.
• In Default mode, write the roadmap artifact only after enough context is available.
• During planning-only roadmap creation, do not execute test suites, builds, formatters, generators, or migrations. Capture end-to-end verification commands in the roadmap without running them.
• Use local truth first: read named specs, AGENTS.md, and repo docs the user explicitly points at. Do not invent phases from vague context.
• Use PMCP for external capability research when current docs or third-party tooling facts affect the roadmap. Prefer gateway_catalog_search, then gateway_describe, then gateway_invoke; use Context7 for library/product docs. Use Bright Data only if PMCP exposes it in the current environment.
• Use request_user_input only when available; in Default mode ask one concise plain-text question only if a missing decision would make the roadmap wrong.
• Prefer fewer serial phases and more parallel work inside each phase. A phase boundary exists only when a contract must freeze before downstream work starts.
• Do not spawn subagents unless the user explicitly asks for agents, subagents, delegation, or parallel agent work.

Inputs

• Optional spec path: markdown file to fold into the roadmap.
• Optional output path: default specs/phase-plans-v<N>.md, choosing the highest existing version or v1 if none exists.
• Append mode: if the output roadmap exists, add phases without rewriting prior phases unless the user explicitly requests a replacement.
• Multi-roadmap disambiguation: when several specs/phase-plans-v*.md exist, default to the highest version but confirm the intended target before writing. Each roadmap file is its own alias namespace — create mode starts a fresh namespace for a new version, and append mode must reuse the existing file's aliases without renumbering or colliding with them. Never fold a new initiative into an unrelated newer roadmap just because it is the latest version; a new initiative is a new roadmap (create mode), not an append.

Workflow

1. Resolve repo root with git rev-parse --show-toplevel, then inspect:
   • the named spec, if any;
   • AGENTS.md and CLAUDE.md, if present;
   • existing specs/phase-plans-v*.md;
   • markdown files the user named.
2. Choose create or append mode:
   • Create mode writes a full roadmap.
   • Append mode reads existing aliases, phase numbers, dependencies, and interface gates, then appends only new phases.
3. Write top-level context:
   • Context
   • Architecture North Star when structural
   • Assumptions
   • Non-Goals
   • Cross-Cutting Principles
4. Decompose into phases:
   • serial phases only at interface-freeze boundaries;
   • sibling phases for independent subtrees;
   • at least two likely lanes per implementation phase unless it is a preamble or interface-only phase;
   • explicit Depends on and Produces entries.
5. Add:
   • Top Interface-Freeze Gates;
   • Phase Dependency DAG;
   • Execution Notes that name which phases can be planned or executed concurrently;
   • end-to-end Verification commands.
6. Validate mechanically, then by eye:
   • run phase-loop validate-roadmap <output-path> (or python3 -m phase_loop_runtime.roadmap_lint <output-path>) — always available wherever the phase-loop runtime is installed; it mechanically checks stable headings, unique aliases, acyclic DAG, IF-gate reconciliation, and the lane-count hint. Fix every reported issue, then confirm by eye:
   • stable headings are present;
   • aliases are unique;
   • dependency graph is acyclic;
   • every produced gate has a producing phase;
   • append mode did not silently rewrite old phases.

Validator Format Contract

phase-loop validate-roadmap (the phase_loop_runtime.roadmap_lint module) parses by regex on stable headings, not a full Markdown parser, so these formatting rules are load-bearing — a violation drops the phase, mis-parses a field, or trips a structural check rather than warning politely:

• Phase heading shape is ### Phase N — <Name> (<ALIAS>). The alias must match [A-Za-z0-9]+ — letters and digits only, no spaces, hyphens, underscores, or punctuation — and nothing may follow the closing ) on that line. Trailing decoration after (ALIAS) makes the heading malformed. Use UPPERCASE aliases (SKILLREF, P2A), the convention every roadmap follows: a lowercase alias parses in the heading but its Depends on references will not resolve, because the dependency parser uppercases the tokens it reads while the phase's own alias is compared as written.
• A malformed heading cascades — fix the heading first. A heading that fails the phase regex is not parsed as a phase at all, so its fields, alias, Depends on, and produced gates disappear and downstream checks (unknown-alias, IF-gate reconciliation, DAG acyclicity) light up with secondary errors. When a heading error appears, correct it and re-run before chasing the rest.
• Each **Field** label sits on its own line, with the field body on the following lines. **Objective** text on the same line is not recognized and reads as a missing field.
• Lists are bulleted: Key files uses - bullets and Exit criteria uses - [ ] / - [x] checkboxes. Prose in place of bullets reads as empty.
• Each exit-criterion leads with a stable goal ID EC-<ALIAS>-<N> (alias = the phase alias): - [ ] EC-<ALIAS>-1 — <assertion>. A downstream plan REFERENCES the ID instead of restating (and drifting from) the goal. Rules: all-or-none per phase (every criterion carries an ID or none do — a mixed phase is a phase-loop validate-roadmap (H) error); unique + alias-scoped; gaps allowed — never reuse or renumber a deleted ID (a plan references it by ID). Runtime goal-coverage checks each ID is referenced by ≥1 plan acceptance item.
• Every implementation phase declares a lane hint in Scope notes (or a **Lanes** block): a literal such as decompose into N lanes, Single lane (with justification), or partition words (disjoint, owns, partition, lane A/lane B), unless the phase is marked preamble/interface-only.
• Required top-level headings, unique aliases, non-decreasing phase numbers, IF-0-<ALIAS>-<n> gate IDs reconciled with Produces, (none) roots, and an acyclic DAG are enforced too. Run the validator and fix every reported issue before hand review.

Artifact Contract

Use this shape so gemini-plan-phase can parse it:

# Phase roadmap v<N>

## Context

## Architecture North Star

## Assumptions

## Non-Goals

## Cross-Cutting Principles

## Top Interface-Freeze Gates
- IF-0-<ALIAS>-<N> — <frozen contract>

## Phases

### Phase N — <Name> (<ALIAS>)
**Objective**

**Exit criteria**
- [ ] EC-<ALIAS>-1 — <testable criterion>

**Scope notes**

**Non-goals**

**Key files**

**Depends on**
- (none)

**Produces**
- IF-0-<ALIAS>-<N> — <contract>

## Phase Dependency DAG

## Execution Notes

## Verification

Spec Delta Policy

Every roadmap phase must declare its expected spec_delta_closeout.v1 policy. Add a phase-local **Spec closeout policy** block that names schema: spec_delta_closeout.v1, the expected decision (no_spec_delta, roadmap_amendment, canonical_spec_update, governed_pipeline_refresh, mirror_cutover_required, dotfiles_skill_source_update, or human_source_judgment_required), target surfaces, evidence paths, redaction_posture: metadata_only, and any non-human blocker_class=contract_bug routing for missing or malformed evidence. Use no_spec_delta for phases that do not change reusable specs, dotfiles_skill_source_update for dotfiles-owned skill/source updates, and downstream routing decisions such as governed_pipeline_refresh or mirror_cutover_required only as metadata-only deferrals, not as write authorization.

Verification Contract

Roadmap phases must set the expectation that downstream plans include machine-checkable verification commands and an effective automation.suite_command. If a phase depends on operational evidence that cannot be machine-checked directly, name the operational evidence artifact and the runner-stamped amendment mechanism that records it. proxy evidence requires a roadmap amendment before any downstream plan treats it as a gate verdict.

Closeout

In Default mode, write the roadmap with the active session's file-editing tool, then run git status --short -- <artifact>. If the artifact is untracked or modified and the user did not explicitly forbid staging, run git add <artifact> and include the _reviews.md sibling if one was produced. Rerun git status --short -- <artifact> and report Artifact state: staged|tracked|modified|unstaged|blocked. Do not commit unless the user asked for a commit.

Before final response and handoff, choose the next phase to plan from the roadmap DAG. If at least one phase is ready, report Next phase: <alias> - <phase name> and Next command: gemini-plan-phase <artifact> <alias>. If no phase should be planned next, report Next phase: none - <reason> and Next command: none - <reason>.

Add a machine-readable automation handoff that agrees with the human-readable next step fields. Closeout payload shape is defined by EmitPhaseCloseout in phase_loop_runtime/baml_src/emit_phase_closeout.baml (if that path is absent in the checkout, use the operator/prompt-supplied field contract or the installed phase_loop_runtime package — the missing vendored BAML source is not a blocker); keep skill text focused on value selection and handoff routing, not duplicated field ceremony.

If a roadmap edit changes downstream scope, amend the nearest downstream phase that is not already executing and treat any older downstream phase plan or handoff as stale until it is regenerated.

Before final response, write a reflection for every non-trivial run. Write it to resolve_skill_bundle_root("codex")/gemini-phase-roadmap-builder/reflections/<repo_hash>/<branch_slug>/<run_id>.md. The reflection must include ## Run context with skill name, ISO timestamp, repo, branch, commit, and artifact path if any, followed by ## What worked, ## What didn't, and ## Improvements to SKILL.md. skip only when no artifact was produced AND no decision was made AND the run was pure inspection.

Resolve closeout writes through the phase_loop_runtime.skill_paths resolver as the primary source — resolve_handoff_root(repo) for the handoff root and resolve_reflection_root(skill_name) for reflection roots; fall back to the repo-local shared/phase-loop/handoff_path.py resolver only when phase_loop_runtime is not importable. Legacy harness handoff roots are read only for migration. Follow gemini-config/shared/runtime-state.md and use Gemini paths only:

• Reflection: resolve_skill_bundle_root("codex")/gemini-phase-roadmap-builder/reflections/<repo_hash>/<branch_slug>/<run_id>.md
• Handoff: <repo>/.dev-skills/handoffs/gemini-phase-roadmap-builder/<run_id>.md
• Latest handoff pointer: <repo>/.dev-skills/handoffs/gemini-phase-roadmap-builder/latest.md

Handoff frontmatter must include from: gemini-phase-roadmap-builder, timestamp:, repo:, repo_root:, branch:, branch_slug:, commit:, run_id:, artifact:, artifact_state:, next_skill:, next_command:, and next_phase:. Update latest.md with the same handoff content.

GOVLEAN Policy

• Content & Behavior Falsifiers: Runtime evidence primitives evaluate content and behavior bound properties; never commit topology or future-history pins to plan specifications.
• External-Only Pins: Pinned inputs are restricted strictly to declared external inputs in a dedicated section.
• Plan Budget: Plan size is governed by a 3000-word budget with explicit justification required above it when exceeded.
• Review Policy: Ratified review requires cross-vendor ablation evidence for all Sol-authored plans.
• Proof-Cost Findings: Flag proof-cost findings when evaluation is constrained to a single node over roughly five minutes or when a test run is unable to report multiple failures.