Cursor rule

1---
2description: Language plugin system — LanguageSupport registry, text/markdown/zig/json plugins
3globs:
4  - src/sdk/**
5  - src/plugins/text/**
6  - src/plugins/markdown/**
7  - docs/PLUGINS.md
8---
9 
10# Language Plugins
11 
12Source of truth: `docs/PLUGINS.md` (markdown lives in `plugins/markdown`, not `core`).
13 
14## Invariants
15 
16- **`text` owns all text documents** — load/save/draw/undo. Language plugins never implement document vtable hooks.
17- **Language plugins register `LanguageSupport` only** — optional `treeSitterHighlight` and/or `previewPane` hooks looked up by extension via `Host.treeSitterHighlightFor` / `Host.previewProviderFor`.
18- **Plugins never import each other** — they meet only at the SDK registry.
19- **`markdown` is a bundled in-tree utility plugin** — owns cmark renderer + `.md` preview; shell imports `@import("markdown")` plugin hub for store READMEs.
20- **`zig` / `json` are external store plugins** in `~/dev/fizzyedit/zig` and `~/dev/fizzyedit/json`.
21 
22## SDK change checklist
23 
24When touching the language boundary:
25 
261. `src/sdk/language.zig` — types
272. `src/sdk/Host.zig` — registry + lookup fns + `unregisterPlugin` cleanup
283. `src/sdk/dylib.zig` — add types to `sdk_boundary_types`
294. `src/sdk/version.zig` — bump `sdk_version` + `recorded_sdk_shape_fingerprint`
305. Run `zig build test-sdk-version`
31 
32## Build rule
33 
34Plugin builds must not leak app-only deps (Velopack). After build-graph changes:
35 
36```sh
37cd src/plugins/image && rm -rf .zig-cache zig-out zig-pkg && zig build -Doptimize=ReleaseFast
38ls zig-pkg | grep -i velo  # must be empty
39```
40