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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context by explicitly stating the tool does not call AI providers, fetch URLs, persist data, or establish current inclusion — this clarifies the tool's limited scope beyond what annotations provide. It doesn't describe the output format, but the output schema exists and the description's exclusions are the key behavioral disclosure.

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?

Two sentences with zero waste. The first sentence states the core function, and the second sentence front-loads the critical exclusions. Every word earns its place, and the structure is ideal for an agent scanning quickly.

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 read-only calculation tool with an output schema and clear annotations, the description is nearly complete. It explains the input contract (caller-supplied captures), the computation (mention and business-citation rates), and the boundaries (no provider calls, no fetching, no persistence, no current inclusion). The only minor gap is not describing the output shape, but the output schema exists and the tool's complexity is moderate.

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?

Schema description coverage is 50% — the 'observations' parameter has a description ('Point-in-time captures supplied by the caller. The tool will not obtain new captures.'), but 'businessName' has no description. The tool description adds context about what the tool does with these parameters (calculates rates from captures), but doesn't add per-parameter semantics beyond the schema. With 50% coverage, the description partially compensates but doesn't fully close the gap for businessName.

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 uses a specific verb ('Calculate') and names the exact resource ('mention and business-citation rates from caller-supplied captures'). It also distinguishes itself from siblings by explicitly stating what it does NOT do (call AI providers, fetch URLs, persist data, establish current inclusion). This makes the tool's purpose unmistakable.

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?

The description clearly states the tool operates on caller-supplied captures and explicitly lists exclusions (does not call AI providers, fetch URLs, persist data, or establish current inclusion). This gives strong context for when to use it, though it doesn't explicitly name alternative tools or provide a when-not-to-use condition beyond the exclusions.

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