leptos-lookup

name	leptos-lookup
description	Finds and reads the authoritative Leptos guidance for a topic (signals, effects, <For>, resources, Suspense/Transition, server functions, extractors, SSR modes, hydration bugs, router, ActionForm, islands, binary size) in the official Leptos book, cached locally. Use before implementing or reviewing any admin-UI (app/ehrbase-admin-ui) behaviour the rule file doesn't fully settle, or when a "how does Leptos do X" question comes up.
allowed-tools	["Read","Grep","Glob","Bash"]
argument-hint	<signal / resource / hydration / server fn / router topic>

/leptos-lookup

Answer Leptos questions from the official book text — never from memory (Leptos is pre-1.0 and moves fast; training data drifts). The distilled rules live in .claude/rules/leptos-ui.md; this skill is for going back to the source when a case isn't covered or needs the full context.

Procedure

1. Ensure the book cache exists (shared, survives sessions):

   BOOK=~/.cache/ehrbase-rs/leptos-book
   [ -d "$BOOK/src" ] || git clone --depth 1 https://github.com/leptos-rs/book "$BOOK"
   

   If the cache is older than ~30 days (git -C "$BOOK" log -1 --format=%cr), git -C "$BOOK" pull --ff-only first. The book's main targets the current Leptos 0.x line — cross-check any version-sensitive answer against the pinned Leptos version in the UI crate's Cargo.toml.

2. Route to the owning chapter (src/SUMMARY.md is the index):

   • signals / effects / memos / derived → src/reactivity/*, appendices appendix_reactive_graph.md, appendix_life_cycle.md
   • components / props / children / context → src/view/03…09_*, src/interlude_projecting_children.md
   • lists & keys → src/view/04_iteration.md, 04b_iteration.md
   • control flow / errors → src/view/06…07_*
   • forms → src/view/05_forms.md; progressive enhancement → src/progressive_enhancement/*
   • async (Resource/Suspense/Transition/Action) → src/async/*
   • server fns / extractors / responses → src/server/*
   • SSR modes / page lifecycle / hydration bugs → src/ssr/*
   • router → src/router/*; global state → src/15_global_state.md
   • islands → src/islands.md; WASM size / deployment → src/deployment/*; styling → src/interlude_styling.md; head/meta → src/metadata.md; testing → src/testing.md; web_sys/JS interop → src/web_sys.md

3. Grep the exact API name (Suspend, ForEnumerate, bind:value, extract_with_state, …) across src/**/*.md when the routing isn't obvious.

4. Read the surrounding section, including the warnings/admonish blocks — the book's DON'Ts live there.

5. Answer with citations (<chapter>.md + heading). For API-signature detail beyond the book, follow its docs.rs links via Context7/WebFetch rather than guessing. If the answer belongs in the standing rules, propose the .claude/rules/leptos-ui.md addition explicitly.