Cross-Project Cost Summary

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

Annotations already provide readOnlyHint, destructiveHint, idempotentHint. Description adds that results are sorted by total spend and include percentage, which is not in annotations. No contradiction. It does not mention rate limits or data freshness, but annotations cover safety adequately.

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, no wasted words. First sentence states the main result, second sentence details output fields, third sentence gives usage guidance. Front-loaded with action verb.

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?

Description explains what the tool returns and when to use it. It lacks details about default date ranges (handled in schema) and output format specifics, but is sufficient for an agent to select and invoke correctly given the annotations and schema coverage.

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 baseline is 3. Description does not add extra parameter semantics beyond the schema; it only restates the tool's purpose. No new constraints or formats explained.

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 returns a combined cost breakdown across multiple GCP projects, sorted by total spend. It lists the returned fields (name, total cost, percentage). The verb 'returns' is specific and the resource is well-defined. It distinguishes from sibling tools like get_cross_subscription_costs by specifying GCP.

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?

Description explicitly mentions three use cases: when user asks about costs across all GCP projects, wants to compare spending, or needs organization-wide overview. It does not explicitly say when not to use, but the context and sibling list imply it's for GCP only. Could mention alternatives like get_cross_subscription_costs, but still clear.

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