Apilookup

API Lookup Skill

Look up API documentation, SDK references, library versions, and migration guides using a three-tier resolution strategy that starts with local Flow skill references and escalates to targeted web searches only when needed.

Overview

Three tiers of resolution, applied in order:

1. Local skill references — if a matching Flow skill exists and the registry entry is fresh ( 30 days) or the query needs more, use the registry's known URLs for targeted searches (max 2-4).
2. Arbitrary lookup — for technologies without a matching skill, broad web search with a version-first strategy (max 2-4 searches).

Usage Patterns

Example queries this skill handles:

• "What's the latest Litestar version and what changed?"
• "How do I use React Server Components?"
• "Show me the SQLAlchemy 2.0 migration guide"
• "What breaking changes are in Angular 19?"
• "What's the current Go module proxy API?" (arbitrary — no local skill)
• "Check if there's a newer version of Tailwind CSS"

How It Works

Version Registry

references/registry.json maps every Flow skill to:

• Current known version and last-checked date
• Package registry (PyPI, npm, crates.io, etc.)
• Official docs URL, changelog URL, and GitHub repo
• Search hint keywords for targeted queries

Staleness Thresholds

| Age of registry entry | Action | |-----------------------|--------| | 90 days | Treat as potentially outdated, do full version check |

Search Budget

All web lookups are capped at 2-4 searches max. Prefer WebFetch on known URLs over WebSearch when registry URLs are available — it is faster and more precise.

Lookup Rules

See references/lookup-strategy.md for the full decision tree. Key principles:

1. Always start local — check the registry and load matching skill refs if fresh
2. Be targeted — use registry URLs and package names for precise queries
3. Respect the budget — 2-4 searches max, stop once you have an authoritative answer
4. Cite sources — always include links to official docs or changelogs
5. Note version gaps — if local refs cover version X but the current release is Y, tell the user explicitly

References Index

• [Lookup Strategy](references/lookup-strategy.md) — Detailed three-tier resolution instructions
• [Version Registry](references/registry.json) — Package metadata and staleness tracking for all skills
• [Registry Schema](references/registry-schema.md) — Documents the registry JSON format and fields

Validation Checkpoint

Before delivering an answer based on an API lookup, verify:

• [ ] Staleness check was performed against registry.json for known skills
• [ ] Tier 1 (Local) was tried first for fresh entries (

Example: Looking up React Server Components

Query: "How do I use React Server Components in Next.js?"

1. Identify Tech: React, Next.js.
2. Check Registry: Matches react skill. last_checked is 45 days ago (Tier 2).
3. Execute Tier 2:

• Step 1 (Version): WebFetch https://github.com/facebook/react/releases -> React 19 is latest.
• Step 2 (Specific): WebSearch site:nextjs.org react server components pattern 2026.

1. Synthesize:

• "Based on Next.js 15+ documentation (compatible with React 19):"
• Explain use client vs default server components.
• Provide code example of a Server Component fetching data.
• Citations: Next.js RSC Docs, React 19 Upgrade Guide.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: cofin
• Source: cofin/flow
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.