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

Beyond the annotations, the description reveals meaningful behavioral details: the done-column fallback logic ('named done, else the last'), the stamping side effect, the removal from task_list and open counts, and the conditional return of estimate vs actual when both are known. This is rich, non-obvious behavior.

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?

The description is two dense, purposeful sentences. It front-loads the action and then efficiently lists consequences, with no filler or redundant restatement of the tool name.

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 low-complexity tool with one required parameter and no output schema, the description is complete. It explains the main side effects and the only return-value condition; the agent has enough information to invoke it correctly.

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?

The schema already documents the single parameter id, including an example, so description-level parameter detail is not necessary. The description adds no parameter-specific semantics, but schema coverage is 100%, which meets the baseline.

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 uses a specific verb phrase, 'Mark one task finished,' and identifies the exact resource ('one task') and the resulting effect (moves to the done column, stamped). This clearly distinguishes it from siblings like task_delete, task_update, and task_move.

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 clearly implies when to use this tool: when the user wants to complete one task. It does not explicitly name alternatives or state when not to use it, but the semantic contrast with task_update and task_move is strong enough that the intended use is unambiguous.

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