GAQL field metadata

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 context about returned metadata categories and filtering behavior, but it does not disclose response shape, pagination defaults, or how limit applies to results. That is acceptable given the annotation coverage.

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 deliver the core purpose, the query mechanism, and illustrative wildcard patterns with no redundant filler. The most important information is front-loaded, making it easy for an agent to parse 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 metadata lookup tool with four parameters and no output schema, the description covers the primary use case, the key parameter behavior, and the nature of returned metadata. It does not go into depth about output formatting or pagination, but those are not critical for an agent to invoke the tool successfully.

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?

With only 25% schema description coverage, the description compensates well by explaining the intended use of name_like with wildcard examples and by referencing categories (fields, resources, segments, metrics) that map to the category enum. It does not explicitly describe selectable_only or limit, but those are reasonably self-explanatory from their names and schema defaults.

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 opens with a specific verb and object: 'Look up GAQL fields, resources, segments and metrics,' and enumerates the exact metadata returned. It is clearly distinct from sibling gaql_search, which would execute queries rather than describe schema metadata.

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 practical usage context by telling the agent to use name_like with SQL wildcards and provides concrete examples like 'campaign.%' and 'metrics.%conversion%'. It implies this is for metadata discovery rather than data retrieval, though it does not explicitly name gaql_search as the alternative.

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