clade-known-pitfalls
Installation
SKILL.md
Anthropic Known Pitfalls
Overview
Ten common mistakes when building with the Anthropic API and how to avoid them: forgetting max_tokens (required), system prompt in messages array (wrong), non-alternating messages, unchecked stop_reason, creating client per request, no 529 handling, hardcoded model IDs, expensive output tokens, no streaming, and unnecessary PII.
1. Forgetting max_tokens
Unlike OpenAI, max_tokens is required. Omitting it returns a 400 error.
// BAD
await client.messages.create({ model: 'claude-sonnet-4-20250514', messages });
// GOOD
await client.messages.create({ model: 'claude-sonnet-4-20250514', max_tokens: 1024, messages });