Set task done

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

Goes beyond the annotations (readOnlyHint=false, idempotentHint=true, destructiveHint=false) by stating the blast radius: only the one task changes and 'the rest of the list stays as it was,' plus the return shape ('the whole list after the change'). That is exactly the mutation-scope context an agent needs.

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, front-loaded with the action, then the targeting/return semantics, then the edge-case caveat. Every sentence adds information; nothing is restated from 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?

There is no output schema, and the description compensates by saying it returns the whole list after the change. Mutation scope, idempotence implications, and parameter disambiguation are all covered for a 4-parameter 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 coverage is 100%, so the baseline is 3; the description earns extra by clarifying the polymorphic 'task' parameter (id or exact text) and giving a tie-breaking rule for duplicate text that the schema does not state.

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?

Specific verb + resource: 'Tick or untick one task in a to-do list', with the scope (one task, rest unchanged) made explicit. No sibling tool does this, and the definition makes that unambiguous without requiring comparison of schemas.

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?

Provides clear operational guidance on how to target the task ('by task_id or by its exact text') and a disambiguation rule: 'When two tasks share the text, pass the task_id instead.' It doesn't name alternative tools, but no genuine sibling alternative exists for this operation.

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