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

Annotations already signal a non-read, non-destructive state change (readOnlyHint=false, destructiveHint=false). The description adds 'closes it' and the source of task_id, but does not cover idempotency, side effects on subtasks, or auth requirements. This is acceptable given the annotations but not especially rich.

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, front-loaded with the action, no filler. The essential information is stated efficiently and every word earns its place.

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 one-parameter tool with an output schema and annotations covering the side-effect profile, the description supplies the essential invocation context: the action and the id source. It omits edge-case behavior like repeated completion, but nothing required for a basic correct call is missing.

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 adds meaningful provenance by telling the agent to pass the task_id returned by todoist_list_tasks, which goes beyond the schema's generic 'The task id to complete'.

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?

Description opens with a specific verb and resource ('Mark a Todoist task complete') and clarifies the behavior with 'closes it'. It also anchors the id source to todoist_list_tasks, which helps distinguish this from other completion tools like complete_omnifocus_task and complete_reminder.

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 provides clear prerequisite context by instructing the agent to pass the task_id from todoist_list_tasks. It does not explicitly list when to prefer this tool over sibling completion tools, but the Todoist-specific framing and id-source instruction give adequate usage guidance.

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