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

Annotations cover the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false, openWorldHint=false), so the remaining burden is light. The description still adds real value by disclosing the S3 upload side effect, the presigned-URL return, and what the spec contains — behavior an agent cannot infer from the annotations alone.

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, front-loaded with the action and side effect, then the return value, then scope clarification. Every sentence earns its place, though the scope sentence is somewhat lengthy for the marginal point it makes.

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?

There is no output schema, but the description explicitly states what is returned (a presigned URL) and what the artifact contains. Combined with the annotation safety profile and a fully documented single parameter, an agent has everything needed to call 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 schema already explains the project_id field including the whoami default_project_id fallback. The description adds nothing further about the parameter, so the baseline 3 applies.

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?

States a specific verb (Generate) and resource (OpenAPI 3.0 spec) plus the side effect (upload to S3) and the return (presigned URL). No sibling tool does anything comparable, so it is trivially distinguishable from the create_/list_/update_ family.

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 second sentence clarifies an important boundary — the generated spec describes the project's REST API and 'this MCP does not proxy data CRUD' — which steers agents away from misusing it. It does not, however, state explicitly when in a workflow to call it (e.g. after entities/endpoints are defined) or name an alternative.

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