Slice 11 / Phase 1 (v2): Article collection spine — schema, dual-format, feeds, listing

[tkowalczyk]

Parent PRD

#12

What to build

A thin vertical slice that validates the architecture before any article is written.

Define the article content collection with its Zod schema, including the series discriminator (enum: build-log | essay) and the conditional episode_number requirement (required when series === "build-log"). Define the independent SCHEMA_VERSION_ARTICLE marker.

Commit one placeholder article entry (real frontmatter shape, throwaway prose, episode_number: 0 reserved for stubs). Verify that the existing Dual-Format Serving deep module from PRD #1 resolves both /articles/<slug> and /articles/<slug>.md without per-route code. Verify that the existing Feed Generators deep module includes the new collection in rss.xml, llms.txt, sitemap.xml without code changes.

Build the /articles/ listing page as composition over the collection — sorted by episode_number ascending for build-log entries, inline by date for essays.

Extend the schema-rejection tests to cover article-specific malformed cases. Extend the dual-format integration tests to iterate over the new collection.

See plans/slice-11-build-log.md Phase 1 for full details.

Acceptance criteria

• article content collection with Zod-validated frontmatter is live; SCHEMA_VERSION_ARTICLE marker is defined and exported
• A PR that adds a markdown file with malformed article frontmatter (missing required field, wrong series enum, missing episode_number when series === "build-log", malformed commit_range) fails CI before merge; error message identifies the bad field
• The placeholder article resolves at /articles/<slug> (200 text/html) and /articles/<slug>.md (200 text/markdown) with body matching the source markdown
• rss.xml, llms.txt, and sitemap.xml include the placeholder article alongside existing statements
• Feed snapshot tests are deterministic over a fixture set that contains both statements and articles
• /articles/ listing page renders the placeholder, sorted by episode_number ascending
• pnpm types && pnpm test && pnpm lint && pnpm knip all pass in CI

Blocked by

None — can start immediately.

User stories addressed

Reference by number from PRD #12:

• User story 12 (LLM agent — .md ingestion)
• User story 13 (LLM agent — llms.txt listing)
• User story 14 (LLM agent — RSS inclusion)
• User story 16 (author — schema enforces required frontmatter)
• User story 19 (author — series discriminator)
• User story 20 (author — commit_range as internal metadata)