Advanced Tool Use (API)
4 Tool Use API features launched in GA in February 2026: Prompt Tool Caching (-37% tokens), Dynamic Tool Filtering (additional -24% tokens), Tool Search Tool (-85% context usage), Tool Use Examples (72% → 90% accuracy). All activatable via Anthropic API parameters without changing your architecture.
Strengths
- Prompt Tool Caching: -37% tokens on sessions with many defined tools
- Dynamic Tool Filtering: additional -24% tokens by hiding irrelevant tools
- Tool Use Examples: 72% → 90% accuracy, significant improvement without fine-tuning
- Tool Search Tool: -85% context usage when an LLM dynamically selects its tools
Limitations
- Only via direct Anthropic API, not available in the standard Claude.ai interface
- Requires Anthropic API mastery to correctly configure each feature
Best for
- Production applications with tool-heavy sessions, immediate ROI on token cost
- Agents with 20+ defined tools, Tool Search Tool drastically reduces context overhead
- Projects with high Tool Use error rates, Tool Use Examples improves accuracy without fine-tuning