list_services

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

No annotations are provided, so the description carries the full burden. 'Lists' implies a read-only operation, but the description does not explicitly state that it is safe/non-destructive, nor does it disclose what it returns (e.g., list of service names vs. full objects), pagination behavior, or error cases. This is a significant gap for a tool with zero 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?

The description is a single sentence with no waste. It is front-loaded with the verb and resource, and includes both parameter scopes. This is appropriately concise and well-structured.

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 list operation with two fully described parameters and no output schema, the description is adequate in stating the primary function. However, it lacks details on the return format (what fields are included) and any caveats (e.g., pagination, absence of results). The agent can infer a list is returned, but not the structure. This is acceptable but not fully complete.

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%, with both 'project' and 'region' having descriptions. The tool description adds no parameter information beyond what the schema provides, so baseline 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 uses a specific verb ('Lists') and a specific resource ('Cloud Run services in a given project and region'). This clearly distinguishes it from get_service (singular) and from deployment-related siblings. The scope (project and region) is explicitly mentioned, matching the parameters.

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?

No guidance is provided on when to use this tool versus alternatives. It does not mention that get_service retrieves a single service or that listing is for multiple services. There is no explicit context, exclusions, or alternative routing.

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