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

Annotations declare readOnlyHint=false and destructiveHint=false, already conveying mutation without destruction. The description adds a meaningful guardrail by stating that confirm=true is required before the action will execute, which is a behavioral constraint beyond the structured annotations.

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 short sentences with the action front-loaded. Every phrase earns its place: the platform, the mandatory confirm flag, and the pointer to the To Do alternative. No redundancy or filler.

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 two-parameter mutation tool with a full output schema and annotations, the description covers the essential context: platform, required confirmation, and a cross-platform alternative. Nothing critical 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 description coverage is 100%, so the baseline is 3. The description's 'Requires confirm=true' reinforces the confirm parameter, and 'Reminder ID from list_reminders' in the schema already documents the ID source. No additional parameter meaning is provided beyond the schema.

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 and resource: 'Marks a reminder complete in Apple Reminders (Reminders.app).' It also distinguishes itself from the sibling tool 'todo_complete_task' by directing Microsoft To Do users there, making the tool's scope unambiguous.

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 explicitly states 'Requires confirm=true' as a usage prerequisite and gives a clear alternative: 'For Microsoft To Do use todo_complete_task instead.' This tells the agent exactly when to use this tool versus a related sibling.

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