get_gcp_cost_summary

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

No annotations are provided, so the description carries the burden. 'Fetches' indicates a read-only operation, and the source data (BigQuery billing export) is disclosed. However, it lacks details on permissions, data freshness, aggregation behavior, or potential errors, which would be useful for an agent.

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, with the operative statement first and a usage note second. No unnecessary words or repetition of schema details.

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 read-style tool with two optional enum parameters and no output schema, the description adequately conveys purpose, data source, and typical use cases. It lacks an explicit return type or caveats, but the simplicity of the tool keeps this from being a major gap.

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 already documents both parameters with descriptions and enum values, providing 100% coverage. The description reinforces the period and group_by concepts but adds no new meaning beyond the schema, so a baseline of 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 verb 'Fetches' and the specific resource 'GCP cost breakdown by service and project from BigQuery billing export', distinguishing it from generic or Azure counterparts by naming GCP and the data source.

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 sentence 'Use this to answer questions about overall GCP spend, top spending services, or cost by project' provides clear context for when to apply this tool. It does not explicitly mention alternatives or exclusions, but the usage guidance is explicit enough for typical queries.

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