Up To Date

Rule

Before writing ANY code that touches an external package or API, fetch the real documentation first. Never rely on training data — it is stale by definition.

When This Triggers

• Installing a package (npm install, pip install, brew install)
• Importing or using any third-party library
• Calling any external API (REST, GraphQL, SDK methods)
• Modifying existing integration code
• Debugging API calls that silently fail

Mandatory Steps

1. Check Version

# What's installed?
cat node_modules/<pkg>/package.json | grep '"version"'
# or: pip show <pkg> | grep Version

# What's latest?
npm info <pkg> version
# or: pip index versions <pkg>

Update if more than 1 major version behind.

2. Fetch Real Docs (pick one or more)

Context7 (preferred for popular libraries):

resolve-library-id → query-docs with specific endpoint/method question

Browser (fetch_webpage):

Fetch the official API reference page for the specific endpoint or method being used

DeepWiki (if available):

Fetch from deepwiki.com for GitHub-based packages

Do NOT skip this step. Do NOT write integration code from memory.

3. Compare Code vs Docs

Check for mismatches:

• Parameters code sends vs parameters docs accept
• Endpoint paths code hits vs current paths
• Response shape code expects vs current shape
• Required vs optional fields
• Removed or renamed parameters

4. After Changes

• Remove deprecated env vars and parameters
• Update all call sites
• Build to verify types
• Test live and verify the actual downstream effect — don't just check the HTTP status code. Confirm the resource appears where expected (dashboard, database, UI). A 200 with a valid-looking response body can still mean nothing happened.

Why This Matters

Real incident: Resend deprecated Audiences and replaced them with Segments. contacts.create() without a segments parameter still returned 200 and a valid contact object — but the contact was a global orphan invisible in the dashboard. First fix removed audienceId (training data said it was gone). Second fix added segments: [{ id }] after fetching real docs. The 200 OK trap delayed discovery twice.

Anti-Patterns

Bundled Resources

scripts/check_versions.py

Automated version checker for npm and pip packages. Run it to quickly identify outdated dependencies:

# Check a single npm package
python3 scripts/check_versions.py npm resend
# Check all package.json dependencies
python3 scripts/check_versions.py npm --all
# Check a pip package
python3 scripts/check_versions.py pip requests

references/doc-urls.md

Quick-reference table of official API documentation and changelog URLs for 30+ popular packages (email, payments, AI, databases, auth, cloud, analytics, frameworks). Consult this before searching — the correct URL may already be listed.

Related Skills

• dependency-management — use alongside when resolving version conflicts or managing lockfiles
• third-party-integration — use alongside when implementing the actual integration patterns after verifying docs
• api-versioning-strategy — use when designing your own API's versioning, not checking upstream