get_extension_performance

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states 'Get', implying a read operation, but doesn't disclose what data is returned, whether extensions are required to be filtered, any rate limits, or other behavioral traits. This is a significant gap for a tool that could be expected to provide detailed metrics.

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?

The description is a single, front-loaded sentence with no unnecessary words. It is concise and readable, though it borders on under-specification. However, as a structural and sizing evaluation, it earns a high score for efficiency.

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?

The tool has 2 parameters, no output schema, and no annotations. Given this context, the description is not complete. It fails to explain return format, time ranges, filtering behavior, or how it relates to similar performance tools. A more complete description is needed to support correct invocation.

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 coverage is 100% (both parameters have descriptions), but those descriptions are terse: 'Google Ads customer ID' and 'Type of extension'. The tool description does not add any meaning beyond the schema. The baseline for high coverage is 3, and the ambiguity of 'Type of extension' (no enum or examples) is not compensated, so a 3 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 clearly states a specific verb+resource: 'Get extension performance metrics'. It distinguishes the resource (extension performance) from more generic performance tools, but doesn't explicitly differentiate from sibling tools like get_asset_performance or get_campaign_performance, so a small deduction is applied.

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 gives no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites, common use cases, or exclusions. The only implicit signal is the name itself, which is insufficient for an agent deciding between multiple performance-reporting tools.

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