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

Annotations already declare idempotentHint=true and destructiveHint=false, so the 'Idempotent' sentence largely restates structured data. It does add one genuinely new detail: that the call succeeds and reports 'already_completed' rather than erroring, which is useful behavior beyond the 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?

Two short sentences, action front-loaded, and the idempotency behavior immediately after. No filler or redundancy in wording.

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?

An output schema exists, so return shape need not be explained, and the annotations carry the safety profile. However, the expected_version parameter is a meaningful mutation-control feature left unexplained, which is a real gap for a state-changing tool.

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 0% for two parameters. The description explains nothing about task_id's numeric-string format or, more importantly, the optional expected_version optimistic-concurrency guard, whose semantics (what happens on a version mismatch) are entirely undocumented.

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 and resource ('Mark a task done'), which is clearly distinguishable from siblings like update_task or get_task. It does not explicitly name the alternative for changing a task's status, so it falls just short of a 5.

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 intended action is implied by the name and the phrase 'Mark a task done', but there is no explicit guidance on when to prefer this over update_task for a status change, nor on any preconditions (e.g. permissions, whether the task must be assigned to the caller).

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