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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds useful behavioral context beyond that: only active credentials are returned, the scope is the current app, and the operation maps to GET /manage-certs/google. It also warns against inventing other paths, which is a practical behavioral constraint.

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 compact and front-loaded. The title line is followed by a one-sentence behavioral summary, then the scope and endpoint mapping, and a final constraint. Every sentence adds relevant information without noticeable redundancy.

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-only listing operation with one optional parameter and no output schema, the description is complete: it states what is returned, the scope, the endpoint, the required service scope, and the API/rate-limit context. Nothing essential is missing for an agent to invoke it correctly.

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%, and the only parameter, x_app_id, already has a clear description in the schema. The tool description does not add any parameter-level meaning beyond what the schema provides. Baseline 3 is appropriate because the schema carries the full burden.

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 the specific verb 'List' with the resource 'Google credentials' and then clarifies behavior: 'Returns all active Google Wallet credentials for the current app.' This clearly distinguishes it from sibling tools like listCertificates or testGoogleConnection. The OpenAPI operationId and path mapping further remove ambiguity.

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 clear context: it returns active Google Wallet credentials scoped to the current app, and it explicitly says 'Same PassFast HTTP API, billing, and rate limits. Do not invent other paths.' It does not explicitly name alternatives or exclusions, so the usage guidance is clear but not fully comprehensive.

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