rustdoc JSON → Fumadocs API pipeline

Status: Deferred — Phase 3

Problem

cargo doc HTML output is never published, lives in target/doc/, and is hard to navigate. The //! module contracts (once written) deserve a browsable, searchable home that integrates with the rest of the docs site.

Goal

Replace cargo doc with a bun TypeScript build script that consumes rustdoc --output-format json and generates Fumadocs MDX pages at docs/content/docs/internal/api/.

Pipeline

cargo +nightly rustdoc --output-format json -p jackin --document-private-items
→ target/doc/jackin.json
→ docs/scripts/gen-rust-api.ts  (new bun TypeScript script)
→ docs/content/docs/internal/api/<module>/<Item>.mdx  (gitignored)

API docs become browsable at jackin.tailrocks.com/internal/api/ — cross-linked to behavioral specs.

Key design decisions (to confirm)

1. What to include: All pub items + private items with //! or /// docs.
2. URL structure: jackin.tailrocks.com/internal/api/runtime/LoadOptions/
3. Cross-links: Hardcoded map in the script from type name → spec URL (e.g. OpPickerState → /internal/specs/op-picker/)
4. Nightly requirement: CI adds a separate step with dtolnay/rust-toolchain@nightly — isolated from the stable check job.
5. Generated files: .gitignored — regenerated on each bun run build.

Connection to future project

The gen-rust-api.ts script is the prototype for a generalized modern docs.rs alternative (see §11 in the research archive). Once it works for jackin, the processing layer can be extracted and applied to any crate's rustdoc JSON output — an AI-friendly alternative to cargo doc and docs.rs.

Do not do before

Module contracts (//! docs) — the pipeline value scales with //! coverage. Do after the //! sprint.