Harden generate-spec: build-time intake, SKILL↔guide seam, Decision Ledger + §0 pre-build gate

[Carr1005]

Hardens the generate-spec skill and its guide so a generated spec.md is buildable, reproducible, and surfaces its design decisions to the learner. Four commits, each a distinct fix found by running a course (agent-memory) through the loop.

Commits

1. Make learner intake a build-time input, not a generation input (e1d2b3f)
   One spec.md serves many learners, so the generator can't collect a specific learner's project. Intake becomes a build-time substitution: every learner-specific value is emitted as a [slot] carrying a course-derived default, so the spec builds as-is with zero intake and the generator never blocks asking for a project.

2. Harden the SKILL.md ↔ guide seam; track the eval suite (0eae7fe)
   Keep the spec-quality contract in one place. SKILL.md defers entirely to references/spec-generation-guide.md ("do not restate its rules here") so the two files can't drift into two sources of truth.

3. Untrack generate-spec evals/; keep the contract in the guide only (772611e)
   Point-in-time eval artifacts were a second source of truth that drifts from the guide. Untracked via .gitignore; the durable spec-quality contract lives in the guide's §3/§13/§14.

4. Add Decision Ledger + §0 pre-build gate to the guide (a45e738)
   The core restructure of how a spec surfaces design decisions, fixing three failure modes observed run-to-run:

   • Decision Ledger (§5.5, §6) replaces the fixed six-slot intake table with one course-derived, reviewable table of every point where a build could diverge — learner-context AND pattern-critical / course-contradicted technique & dependency decisions — each pinned to exactly one buildable default. Adds the invariant/options/default/trade-off/owner row anatomy and a surfacing bar.
   • §3 dependency precedence so a heavy course dependency (e.g. a cloud DB) resolves to one baked default — substitute-local unless the tech is the taught subject — never a menu or contract (new traps §12.8/§12.9, closing an observed non-determinism where one generation baked a local store and another emitted a menu).
   • §0 "Before you build — REQUIRED" gate (§6.0): an imperative, build-agent-addressed, mechanism-agnostic instruction (works for Claude Code / claude.ai / Codex / Cursor / a custom harness) to present every Ledger row (labeled "course default") and hard stop — end the turn and wait for the user's reply before writing any code — with no "proceed on no response" escape (new trap §12.10, which that escape would re-open).
   • Demotes CTX-C to reference-only, adds the owner provenance label (§9), and adds matching §14 pre-handoff checks.

Scope / notes

• Touches only the harness: spec-generation-guide.md, SKILL.md, .gitignore. No course content ships (courses/* is gitignored by policy — per-user workspace).
• The §0 gate is a portable prose mechanism: it maximizes cross-environment compliance but is not a hard guarantee (only a PreToolUse hook could enforce, which isn't portable to an arbitrary learner environment — deferred).

🤖 Generated with Claude Code