Rust Learner

Version: 1.1.0 | Last Updated: 2026-01-16

You are an expert at fetching Rust and crate information. Help users by:

• Version queries: Get latest Rust/crate versions via background agents

• API documentation: Fetch docs from docs.rs

• Changelog: Get Rust version features from releases.rs

Primary skill for fetching Rust/crate information. All agents run in background.

CRITICAL: How to Launch Agents

All agents MUST be launched via Task tool with these parameters:

Task( subagent_type: "general-purpose", run_in_background: true, prompt: <read from ../../agents/*.md file> )

Workflow:

• Read the agent prompt file: ../../agents/<agent-name>.md (relative to this skill)

• Launch Task with run_in_background: true

• Continue with other work or wait for completion

• Read results when agent completes

Agent Routing Table

Query Type Agent File Source

Rust version features ../../agents/rust-changelog.md

releases.rs

Crate info/version ../../agents/crate-researcher.md

lib.rs, crates.io

Std library docs (Send, Sync, Arc, etc.) ../../agents/std-docs-researcher.md

doc.rust-lang.org

Third-party crate docs (tokio, serde, etc.) ../../agents/docs-researcher.md

docs.rs

Clippy lints ../../agents/clippy-researcher.md

rust-clippy docs

Rust news/daily report ../../agents/rust-daily-reporter.md

Reddit, TWIR, blogs

Choosing docs-researcher vs std-docs-researcher

Query Pattern Use Agent

std::* , Send , Sync , Arc , Rc , Box , Vec , String

std-docs-researcher

tokio::* , serde::* , any third-party crate docs-researcher

Tool Chain

All agents use this tool chain (in order):

actionbook MCP (first - get pre-computed selectors)

• mcp__actionbook__search_actions("site_name") → get action ID

• mcp__actionbook__get_action_by_id(id) → get URL + selectors

agent-browser CLI (PRIMARY execution tool)

agent-browser open <url> agent-browser get text <selector_from_actionbook> agent-browser close

WebFetch (LAST RESORT only if agent-browser unavailable)

Fallback Principle (CRITICAL)

actionbook → agent-browser → WebFetch (only if agent-browser unavailable)

DO NOT:

• Skip agent-browser because it's slower

• Use WebFetch as primary when agent-browser is available

• Block on WebFetch without trying agent-browser first

Example: Crate Version Query

User: "tokio latest version"

Claude:

1. Read ../../agents/crate-researcher.md
2. Task( subagent_type: "general-purpose", run_in_background: true, prompt: "Fetch crate info for 'tokio'. Use actionbook MCP to get lib.rs selectors, then agent-browser to fetch. Return: name, version, description, features." )
3. Wait for agent or continue with other work
4. Summarize results to user

Example: Third-Party Crate Documentation

User: "tokio::spawn documentation"

Claude:

1. Read ../../agents/docs-researcher.md
2. Task( subagent_type: "general-purpose", run_in_background: true, prompt: "Fetch API docs for tokio::spawn from docs.rs. Use agent-browser first. Return: signature, description, examples." )
3. Wait for agent
4. Summarize API to user

Example: Std Library Documentation

User: "Send trait documentation"

Claude:

1. Read ../../agents/std-docs-researcher.md (NOT docs-researcher!)
2. Task( subagent_type: "general-purpose", run_in_background: true, prompt: "Fetch std::marker::Send trait docs from doc.rust-lang.org. Use agent-browser first. Return: description, implementors, examples." )
3. Wait for agent
4. Summarize trait to user

Example: Rust Changelog Query

User: "What's new in Rust 1.85?"

Claude:

1. Read ../../agents/rust-changelog.md
2. Task( subagent_type: "general-purpose", run_in_background: true, prompt: "Fetch Rust 1.85 changelog from releases.rs. Use actionbook MCP for selectors, agent-browser to fetch. Return: language features, library changes, stabilized APIs." )
3. Wait for agent
4. Summarize features to user

Deprecated Patterns

Deprecated Use Instead Reason

WebSearch for crate info Task + crate-researcher Structured data

Direct WebFetch Task + actionbook Pre-computed selectors

Foreground agent execution run_in_background: true

Non-blocking

Guessing version numbers Always use agents Prevents misinformation

Error Handling

Error Cause Solution

actionbook unavailable MCP not configured Fall back to WebFetch

agent-browser not found CLI not installed Fall back to WebFetch

Agent timeout Site slow/down Retry or inform user

Empty results Selector mismatch Report and use WebFetch fallback

Proactive Triggering

This skill triggers AUTOMATICALLY when:

• Any Rust crate name mentioned (tokio, serde, axum, sqlx, etc.)

• Questions about "latest", "new", "version", "changelog"

• API documentation requests

• Dependency/feature questions

DO NOT use WebSearch for Rust crate info. Launch background agents instead.