Cache statistics

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only, idempotent, and non-destructive. The description adds useful behavioral context beyond annotations: "in-process" reveals the cache is ephemeral and process-local, and "Auth: tool policy gate" discloses an authorization prerequisite. It does not contradict any annotation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short, purposeful sentences. The first sentence leads with the function, the second provides guidance, and the third covers safety/auth. Every sentence earns its place with no redundancy or filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple zero-parameter read-only tool with an output schema and comprehensive annotations, the description is fully complete. It covers purpose, usage, exclusions, auth, and safety. No essential information for invoking the tool correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With zero parameters and 100% schema coverage, the schema is trivially complete. The description reinforces this with "no parameters," so no additional parameter semantics are needed. Baseline 4 for zero-parameter tools is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: "Return entry counts and hit totals for the in-process result/plan cache." It names the sibling tools it is not (plan_cache_get, memory_read), which clearly differentiates it from alternatives in the sibling list.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly says "Use for diagnostics" and "Do not use to read a plan (plan_cache_get) or memory (memory_read)." This provides both the intended context and explicit exclusions, leaving no ambiguity about when to call this tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.