get_ad_performance

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

With no annotations, the description must carry the burden. It discloses the return fields and a prerequisite (BigQuery mode). However, it omits behavioral traits like whether it's read-only, required permissions, rate limits, or error conditions. It is adequate but not comprehensive.

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 sentences, front-loaded with purpose, then return fields, then usage and prerequisite. No fluff or repetition. Every sentence earns its place.

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?

Given 4 undocumented parameters and no output schema, the description is insufficient. It explains output but fails to guide parameter usage. For an agent to use this tool correctly, far more parameter context is needed.

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?

The input schema has 4 parameters with 0% description coverage, and the tool description provides no explanation of the parameters (platform, min_spend, campaign_id, creative_format). The agent has no guidance on valid values or formats, severely hindering correct invocation.

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 returns 'Ad/creative level performance with multi-touch attribution credit' and lists specific metrics. This precisely distinguishes it from sibling tools like get_campaign_performance (campaign-level) and get_keyword_performance (keyword-level).

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 provides explicit usage guidance: 'Use to identify winning creatives for scaling and underperforming ones to pause or rotate.' It also notes the prerequisite 'Requires BigQuery mode.' However, it does not specify when not to use it or mention alternatives.

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