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

Annotations already declare idempotentHint=true and destructiveHint=true; the description complements them with the admin-only auth requirement and the patch semantics (unsent fields untouched), which are not in the annotations. It does not clarify reversibility or how the destructive hint manifests (e.g., overwriting an existing name/date).

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 short sentences, front-loaded with the action, then the permission gate, then the patch behavior. No filler or redundant restatement of the title.

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?

With an output schema present, return values need no explanation, and the description plus annotations cover safety, permission, and partial-update semantics for a 4-parameter tool. Only minor gaps remain, such as whether an admin can target any board and how validation failures surface.

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 coverage is 100%, so name, due_on, achieved and milestone_id are all documented in the schema, with the achieved idempotency rule ('re-sending true keeps the original stamp') already spelled out there. The description's field list largely restates that, adding only the partial-update frame, 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 states a specific verb and resource ('Rename, re-date or mark a milestone achieved'), enumerating the three mutable fields so the agent immediately knows the action's scope. It implicitly separates itself from add_milestone/delete_milestone via the update verb, though it never names a sibling explicitly.

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?

It gives real usage context: 'Board admins only' establishes a permission prerequisite, and 'Omitted fields are left unchanged' tells the agent this is a partial-update call. It stops short of saying when to prefer another tool (e.g., list_milestones to resolve an id) or any exclusions.

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