advanced-tool-uselisted

# Advanced Tool Use ## When to activate User wants to optimize tool use patterns in Claude API applications, reduce tokens from tool definitions or call overhead, improve accuracy on complex tool parameters, or build sophisticated tool-calling workflows. ## When NOT to use - Simple single-tool workflows where overhead optimization is irrelevant - Applications using the standard Messages API with fewer than 5 tools and no repeated calls - Debugging a broken tool definition — fix correctness first, then optimize ## Instructions ### Pattern 1: Programmatic Tool Calling (PTC) Claude writes Python orchestration code instead of calling tools one-at-a-time. Reduces round trips and tokens. **Token reduction: ~37% for multi-tool workflows.** Enable per tool: ```python { "name": "read_file", "description": "Read a file", "input_schema": {"type": "object", "properties": {"path": {"type": "string"}}, "required": ["path"]}, "allowed_callers": ["code_execution_20250825"], } ``` When enabled, Claude may choose to write a Python loop calling this tool N times instead of making N separate tool_use blocks. Use for: repetitive read/lookup patterns, data transformation pipelines, any tool called >3 times per turn. Do not enable for tools with side effects (write, delete, deploy) or tools requiring per-call authorization. --- ### Pattern 2: Dynamic Filtering for Web Tools New built-in tool types for web search and fetch that filter results before they enter context. **B