Research Library

Research $ARGUMENTS and create documentation in .claude/docs/libraries/.

Scope: this skill produces documentation only. It never edits source code and never edits a dependency manifest or lockfile — if the research implies a version bump, report it as an action item instead of making it.

1. Resolve the Document Path

Derive the path once, from the script, and reuse the value everywhere below. $ARGUMENTS is raw user wording (FastAPI, ruamel.yaml, @scope/pkg); the script normalizes it the same way lib_inventory.py normalizes a declared dependency, so the doc filename and the dependency name always match.

python3 .claude/skills/_shared/workspace.py --skill research-lib \
  --title "$ARGUMENTS" --create

Emits {ok, skill, slug, paths: {lib_doc}, dirs, created, artifacts, verify}. Exit 0 on success, 1 on a bad argument. Use paths.lib_doc verbatim from here on — never re-derive it by hand, and never substitute $ARGUMENTS.md.

2. Resolve the Version This Project Uses

The declared and locked versions are facts with one correct answer, so read them instead of asking the web:

python3 .claude/skills/update-lib-docs/lib_inventory.py --library "$ARGUMENTS"

The dependencies array carries {name, declared_spec, declared_in, locked_version, locked_in, ecosystem}. > **Version Checked**: records locked_version when a lockfile pins one, otherwise the version satisfying declared_spec. If dependencies is empty the library is not (yet) a dependency of this project — record the version you are documenting against and say so in ## Constraints & Notes.

Exit codes: 0 ok, 1 bad argument, 2 a manifest could not be parsed (manifest_errors), 3 a library doc could not be read (read_error). On a non-zero exit, stop and report — do not fill the version in from a web search.

Newer upstream releases are research findings, not the project's version: note them under ## Constraints & Notes as an upgrade consideration. The blockquote is the only place a version number lives.

Research Items

Primary Tool: General-Purpose Subagent (Opus)

Use general-purpose-opus with WebSearch/WebFetch for comprehensive library research. Pass the resolved path and version into the prompt:

Agent tool:
  subagent_type: "general-purpose-opus"
  prompt: |
    Research: {library}. Find official documentation, key features,
    constraints, best practices, known issues, and usage patterns.
    Use WebSearch and WebFetch to gather information.
    The version this project uses is {locked_version or declared_spec};
    document against that version, and note newer releases separately.
    Save results to {paths.lib_doc} using the template in
    .claude/skills/research-lib/SKILL.md.
    List every URL you consulted under ## References.
    Return concise summary.

Fallback: WebSearch/WebFetch

If the subagent is unavailable, verify via manual web search:

• Official documentation
• GitHub README
• PyPI / npm page
• Latest release notes

Record every source you used in ## References; a research note whose sources are only in the conversation cannot be audited later.

Content to Document

1. Basic Information

   • Official name, license
   • Official URL
   • Installation command

2. Core Features

   • Main features
   • Basic usage (code examples)

3. Constraints & Notes

   • Known limitations
   • Conflicts with other libraries
   • Performance characteristics
   • Async/sync considerations

4. Usage Patterns in This Project

   • Recommended usage
   • Patterns to avoid

5. Troubleshooting

   • Common errors and solutions

Output Location

paths.lib_doc from step 1 — the only derivation of this path.

Documentation Template

# {Library Name}

> **Last Updated**: {YYYY-MM-DD}
> **Version Checked**: {declared or locked version in this project}

## Overview

- **License**: {license}
- **Official URL**: {url}
- **Installation**: `{install command}`

## Core Features

{Description of main features}

## Basic Usage

```python
{Code example}

Constraints & Notes

• {Limitation 1}
• {Limitation 2}

Recommended Patterns

Do

{Good pattern}

Don't

{Anti-pattern}

Troubleshooting

{Error message}

Cause: {cause} Solution: {solution}

References

• Official Docs
• GitHub

The `> **Last Updated**` / `> **Version Checked**` blockquote is mandatory, not
decoration: `lib_inventory.py` parses exactly those two lines, and a doc without
them is invisible to `update-lib-docs` — never stale, never undocumented, never
maintained.

## Validate the Document

Both checks are gates. Do not report completion until both exit 0.

```bash
python3 .claude/skills/_shared/validate_doc.py --contract lib-doc \
  --file <paths.lib_doc>
python3 .claude/skills/_shared/workspace.py --skill research-lib \
  --slug <slug> --verify

validate_doc.py exit codes:

• 1 — the file does not exist or could not be read. The delegated subagent did not write it (or wrote it elsewhere); the payload has no sections_missing. Re-delegate with paths.lib_doc; do not hand-edit a different path.
• 2 — the file exists but violates the contract. sections_missing lists absent ## sections (Overview, Core Features, Constraints & Notes, References) and metadata_missing lists absent metadata lines (Last Updated, Version Checked). Fill those in and re-run.

workspace.py --verify exit 2 with verify.empty containing lib_doc means the file exists but is a stub (under 20 non-whitespace characters) — a summary was returned without real content.