lookup_ad_performance

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

No annotations are provided, so the description carries the burden. It mentions 'Quick lookup' implying a read operation, and lists the data returned. However, it doesn't disclose any behavioral traits like whether it triggers a sync, whether it requires prior data sync, or what happens if the ad isn't found. The description is adequate but not rich in behavioral context.

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 two sentences: the first states the purpose and data returned, the second gives example queries. It's front-loaded with the key information and has zero waste. Perfectly concise.

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 lookup tool with 2 parameters, 100% schema coverage, and no output schema, the description is quite complete. It covers what the tool does, what data it returns, and example usage. The only gap is not explaining the return format, but since there's no output schema, a brief note on return structure would help. Still, for the tool's simplicity, it's nearly complete.

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 100%, so the schema already documents both parameters (days and ad_name_or_id). The description adds the example usage patterns but doesn't add meaning beyond the schema. The 'partial match' and 'default 7, max 30' are already in the schema. Baseline 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 the tool's purpose: 'Quick lookup of a specific OWN ad's performance' and lists the specific metrics returned (spend, CTR, CPC, impressions, status, genome tags). It also provides example queries ('what's the CTR on [ad]?', 'how is [ad] performing?'), which makes the purpose unmistakable. The emphasis on 'OWN' distinguishes it from competitor-focused sibling tools.

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 clear usage context with example questions, and the 'OWN' qualifier implies it's for the user's own ads, not competitors. However, it doesn't explicitly state when NOT to use this tool or name alternative tools (e.g., list_my_ads for a broader view, or search_competitor_ads for competitor ads). The guidance is clear but lacks explicit exclusions.

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