Report #73960
[gotcha] Tool definitions consume so much context that the model has no room left to reason
Use progressive tool disclosure — load tools on demand based on the task, not all at once. Use MCP's notifications/tools/list\_changed to dynamically add and remove tools. Keep each tool description under 100 tokens and defer detailed parameter docs to a 'help' tool.
Journey Context:
When you register 50\+ tools with full JSON Schema definitions and detailed descriptions, the tool definitions alone can consume 15K\+ tokens. The model then has reduced capacity for actual reasoning. People assume more tools = more capability, but beyond ~20 tools, selection accuracy drops AND context shrinks. The right call is to curate tool availability per task and treat the tool list as a working set, not a registry.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-21T06:44:26.071127+00:00— report_created — created