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

Annotations indicate a mutating but non-destructive operation; the description adds meaningful behavior beyond that: 'Defaults to immediate publish; draft mode requires draftRevision. scheduledAt stages the line draft then schedules it.' This clarifies the publishing workflow and access requirement ('Requires edit access'), which is valuable context not captured by annotations. No contradiction with annotations.

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, each carrying distinct information: the action, the default behavior and draft prerequisite, and the access requirement. It is front-loaded with the core purpose and avoids any redundancy or filler. Ideal length for the information conveyed.

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?

Given the tool's complexity (nested endpoint object, many optional fields), the schema handles detailed parameter semantics. The description covers the key behavioral aspects (publish modes, scheduling) and access requirement, which are essential for correct invocation. It does not describe return values, but there is no output schema and creation tools typically return the created entity, so this is not a critical omission.

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 all parameters are already well-documented in the schema. The description mentions draftRevision and scheduledAt behavior, but these are already covered in the schema's property descriptions. The description does not add extra semantic detail beyond what the schema provides, so a baseline score of 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 states a specific verb and resource ('Create an endpoint under a line'), clearly distinguishing it from sibling tools like create_line and update_endpoint. The phrase 'under a line' anchors the context precisely, and there is no ambiguity about what is being created.

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 provides operational context (default publish behavior, draft mode, scheduledAt) but does not explicitly state when to prefer this tool over alternatives like update_endpoint or create_line. It implies this is for creating new endpoints, but lacks explicit 'when not to use' or alternative routing, which is a gap given the large sibling set.

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