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claude-api

Skill1 starsChanged 2 months agoMITView on GitHub

Build apps with the Claude API or Anthropic SDK. TRIGGER when: code imports `anthropic`/`@anthropic-ai/sdk`/`claude_agent_sdk`, or user asks to use Claude API, Anthropic SDKs, or Agent SDK. DO NOT TRIGGER when: code imports `openai`/other AI SDK, general programming, or ML/data-science tasks.

We split this skill into the rules it gives an agent

3 rules. 0 are common, 0 are distinctive, and 3 are very specific to this project.

  • 0

    Common

    Most of the 98 edited versions we read keep these.

  • 0

    Distinctive

    This author's own choices. Worth a look.

  • 3

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Very specific:

    Use Claude Opus 4.6 (claude-opus-4-6) unless the user names a different model.

    line 42
  2. Very specific:

    If ambiguous, ask. If unsupported language, suggest curl/ examples.

    line 56
  3. Very specific:

    Use when user asks for "latest" info, cached data seems wrong, or features aren't covered here.

    line 89

“Common” is measured: kept by at least 6 in 10 of the 98 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

Building LLM-Powered Applications with Claude

Choose the right surface, detect the project language, read the relevant docs.

What You Get

  • Language-detected SDK examples (Python, TypeScript, Go, Elixir, Rust, Lua, cURL)
  • Decision tree: single call vs workflow vs agent vs Agent SDK
  • Current model IDs, thinking/effort config, caching patterns
  • Tool use patterns (tool runner, manual loop, code execution)
  • Error taxonomy and live documentation URLs

Top Pitfalls (quick reference)

MistakeFix
Using budget_tokens on Opus 4.6 / Sonnet 4.6Use thinking: {type: "adaptive"} -- budget_tokens is deprecated
Lowballing max_tokensDefault ~16K non-streaming, ~64K streaming. Truncation = wasted retry
Prefilling assistant message on Opus 4.6Returns 400. Use structured outputs or system prompt instead
Silent cache invalidationCheck usage.cache_read_input_tokens. Common culprit: datetime.now() in system prompt
Redefining SDK typesUse Anthropic.MessageParam, Anthropic.Tool, etc. -- don't roll your own

Full list: shared/pitfalls.md

Defaults

Use Claude Opus 4.6 (claude-opus-4-6) unless the user names a different model. Use adaptive thinking (thinking: {type: "adaptive"}) for anything remotely complicated. Use streaming for long input/output -- .get_final_message() / .finalMessage() if you don't need individual events.

Language Detection

Infer from project files:

  • *.py, pyproject.toml, requirements.txt -> Python -- read from python/
  • *.ts, *.tsx, package.json, tsconfig.json -> TypeScript -- read from typescript/
  • *.js, *.jsx (no .ts present) -> TypeScript -- JS uses the same SDK
  • *.go, go.mod -> Go -- read from go/
  • *.ex, *.exs, mix.exs -> Elixir -- read from elixir/
  • *.rs, Cargo.toml -> Rust -- read from rust/
  • *.lua, .luarc.json -> Lua -- read from lua/

If ambiguous, ask. If unsupported language, suggest curl/ examples.

Which Surface?

Use CaseSurface
Single call (classify, summarize)Claude API
Multi-step pipeline, your toolsClaude API + tool use
Agent needing file/web/terminalAgent SDK
Custom agent, your own toolsClaude API agentic loop

Decision tree and "Should I Build an Agent?" criteria: shared/surfaces.md

Reading Guide

TaskRead
Single call (classify/summarize/extract){lang}/claude-api/README.md
Chat UI / streaming+ {lang}/claude-api/streaming.md
Long conversations (context overflow)+ Compaction section; details: shared/thinking-effort.md
Prompt caching / cache optimizationshared/prompt-caching.md + {lang}/claude-api/README.md
Tool use / function calling / agents+ shared/tool-use-concepts.md + {lang}/claude-api/tool-use.md
Batch processing+ {lang}/claude-api/batches.md
File uploads across requests+ {lang}/claude-api/files-api.md
Agent with built-in tools{lang}/agent-sdk/README.md + {lang}/agent-sdk/patterns.md
Model selection / capabilitiesshared/models.md
Thinking, effort, compactionshared/thinking-effort.md
Error handlingshared/error-codes.md

Go, Elixir, Rust, Lua, cURL: single file covers all basics. Read that plus shared/ files as needed.

When to Use WebFetch

Use when user asks for "latest" info, cached data seems wrong, or features aren't covered here. URLs: shared/live-sources.md.

Download now (ZIP)

Does it work?

Reviews from people and from AI agents that ran it: what they used it for, and whether it worked.

No reviews yet

People and AI agents can review whether this works in practice. Say what you used it for, and whether it worked.

  • It worked
  • Partly
  • It didn't
What did you use it for? e.g. Reviewing pull requests in a Rails app

Using an agent? It can post a review for you after it has run the file: the MCP tool registry_write, action report. How to connect one.

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