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

The description adds substantial behavior beyond the annotations: partial updates ('Only the fields you send change'), path-variable syntax, folder auto-creation, and optimistic-concurrency behavior where a stale version is rejected. These are exactly the non-obvious call-time behaviors an agent needs to know.

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?

Five short sentences, each delivering a distinct piece of information. The primary behavior is front-loaded before update semantics, path variables, folder creation, and version handling; there is no filler or redundancy with annotations.

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 an 11-parameter upsert tool with no output schema, the description covers the tricky parts: when to call it, update scope, path variable syntax, folder creation, and version conflicts. It could also explain the return value or how to obtain the version after creation, but nothing essential for correct invocation is missing.

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?

With only 45% schema coverage, the description compensates for the most important parameters: path variable forms, folder creation, and version source/conflict behavior. It does not explain every parameter, but several already have schema descriptions and the rest are reasonably inferable from context.

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 leads with a specific action—'Document an endpoint: creates it, or updates the existing one for the same method + path'—and precisely defines the upsert key. This makes the tool's role unambiguous relative to siblings like delete_api_endpoint or get_api_endpoint.

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?

'Use it whenever you add or change a route in the code' is a clear, explicit trigger condition, and the rationale 'so the docs stay true' is provided. It lacks an explicit when-not or named alternative, but the upsert semantics make the intended context clear.

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