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

Annotations already indicate this is a mutating operation (readOnlyHint=false) and not destructive (destructiveHint=false). The description adds the detail that it works via Reminders sync, which is extra context. However, it does not disclose requirements like confirm=true or potential side effects, but the parameter schema covers confirm.

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 a single sentence with no redundant phrasing. It front-loads the core action and includes a useful qualifier. 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?

Given the simple operation and rich structured data (full schema coverage, annotations, and an output schema), the description is sufficient. It could mention the need for confirm=true or retrieving task_id from todo_list_tasks, but the schema already communicates these. The description is complete enough for an agent to invoke correctly with schema awareness.

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 100%, so each parameter is already well-documented. The description adds no additional meaning about parameters, such as which identifier to prefer, but the schema already explains that title is a partial match and alternative to task_id.

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 clearly states the action ('Marks a Microsoft To Do task as complete') with a specific verb and resource. It distinguishes the tool from siblings like complete_reminder and complete_omnifocus_task by explicitly naming Microsoft To Do and the 'via Reminders sync' detail.

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 implies usage context through the name and 'Microsoft To Do' mention, but it does not explicitly state when to use this tool versus alternatives, nor does it provide exclusions or prerequisites. No direct guidance on selecting task_id vs title is given, though the schema covers that.

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