get_channel_efficiency

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

No annotations provided, so description carries full burden. It describes the report contents and column interpretation but lacks details on read-only nature, data freshness, or auth requirements. Adequate but not thorough.

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 concise sentences: report content, column explanation, and use case/requirement. No fluff, front-loaded with key info.

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?

No output schema, but description details output columns (CPA, ROAS, etc.) and the gap metric. Also mentions BigQuery requirement. Sufficient for using the tool, though could add permission or data scope details.

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?

No parameters (input schema empty), so schema description coverage is 100% by default. Baseline 4 applies. Description adds no parameter info but none needed.

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?

Description clearly states it's a cross-channel efficiency report with specific metrics (CPA, ROAS, pipeline share, spend share) and the gap column. Distinguishes from sibling tools by focusing on cross-channel efficiency rather than campaign or benchmark reports.

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?

Explicitly states use case 'Use for budget allocation recommendations' and prerequisite 'Requires BigQuery mode.' While it doesn't list alternatives or when not to use, the guidance is clear and actionable.

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