webspec-index

Query WHATWG, W3C, and TC39 web specifications from the command line.

Features

Full-text search across HTML, DOM, URL, CSS, ECMAScript, and 70+ other specifications
Cross-reference tracking — see incoming/outgoing references between spec sections
Graph traversal — build cross-reference graphs with JSON, Mermaid, or Graphviz DOT output
Auto URL indexing for whitelisted domains — query non-hardcoded specs by URL
Fast SQLite indexing with FTS5 for instant queries
Algorithm and IDL extraction with rendered markdown content
LSP server for inline spec hovers and step validation in your editor
LLM-friendly --help output — automatically detected when run inside Claude Code, Codex, Gemini CLI, or OpenCode

Installation

cargo binstall webspec-index

Or build from source:

cargo install webspec-index

Quick Start

# Look up a spec section (algorithm, definition, heading, IDL)
webspec-index query "HTML#navigate"
webspec-index query "https://html.spec.whatwg.org/#navigate"
webspec-index query "https://w3c.github.io/webappsec-permissions-policy/#permissions-policy-header"
webspec-index query "DOM#concept-tree" --format markdown

# Full-text search
webspec-index search "tree order" --spec DOM

# Check if an anchor exists (exit code 0 = found, 1 = not found)
webspec-index exists "HTML#navigate"

# Find anchors by glob pattern
webspec-index anchors "*-tree" --spec DOM

# List all headings in a spec
webspec-index list HTML

# Cross-references (exact or shorthand)
webspec-index refs "HTML#navigate" --direction incoming
webspec-index refs "Window.navigation" --limit 5

# Graph traversal
webspec-index graph "HTML#navigate" --max-depth 2 --graph-format mermaid
webspec-index graph "HTML#navigate" --graph-format dot
webspec-index graph "HTML#navigate" --same-spec-only
webspec-index graph "HTML#navigate" --include "*concept-*" --exclude "re:^URL#"

# Query dedicated WebIDL definitions
webspec-index idl "HTML#dom-window-navigation"
webspec-index idl "Window.navigation"
webspec-index idl "Window.open()" --spec HTML

# Update specs to latest versions
webspec-index update

All commands support --format json (default) or --format markdown.

Spec data is fetched and cached locally on first query — no setup needed.

Spec refreshes are freshness-based: once checked, a spec is considered fresh for 24h. When refreshed, the CLI fetches live HTML and re-indexes only if content changed.

AI Agent Integration

Skill file

Drop SKILL.md into your repo to teach the agent how to use the CLI.

Editor Integration

The webspec-lens extension provides inline spec hovers, step validation, and coverage tracking. Available for VS Code and any LSP-compatible editor.

See editors/vscode/ and editors/zed/ for details.

How It Works

Fetches spec HTML from WHATWG/W3C/TC39 spec URLs
Parses sections, algorithms, IDL definitions, and cross-references
Indexes in SQLite with FTS5 for fast full-text search
Refreshes snapshots on a 24h cadence with content-hash change detection

Development

cargo test
cargo clippy        # lint
cargo fmt --check   # format check

License

MIT

webspec-index 0.7.0