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

No annotations are provided, so the description carries the full burden. It discloses the recurring-task behavior (auto-spawning next occurrence), which is valuable. However, it omits any side effects, reversibility, or return behavior. For a mutation tool without annotations, this is a gap, though the core mutation is implied.

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 sentences, front-loaded with the core action and a useful caveat. No fluff or redundancy.

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 a simple completion action with one parameter, the description covers the main action and a key behavior (recurring). However, it omits any mention of response format, errors, or prerequisites (e.g., task must exist). Without annotations or output schema, this is a minor gap but acceptable for a simple 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% and the description does not explain the 'id' parameter. The tool name and context imply 'id' is the task identifier, but the description fails to explicitly state this. With low schema coverage, the description should compensate but doesn't.

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+resource: 'Mark a task done'. It clearly distinguishes from sibling tasks_update (which implies editing fields) by focusing on completion. The recurring task note adds context without muddying the primary purpose.

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 provides a clear usage hint: for recurring tasks, the server auto-spawns the next occurrence, so the agent doesn't need to create it manually. This implicitly guides against using tasks_create for the next occurrence. However, it doesn't explicitly contrast with tasks_update or tasks_delete, but the action is clear enough.

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