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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the agent knows it is a mutation. The description adds the detail that it can either mark done or delete, but does not explain side effects, reversibility, or what happens on success. It does not contradict annotations, but adds limited behavioral context.

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?

A single sentence with no filler. The primary action is front-loaded, and the alternative is mentioned in a parenthetical. Extremely concise and to the point.

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 destructive mutation with an output schema, the description is too sparse. It does not explain prerequisites, error conditions, or the precise behavior of the delete parameter. Given the tool's destructive nature, more context is needed to ensure correct usage.

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 0%, so the description must explain the parameters. It mentions 'delete it', hinting at the delete boolean, but does not explicitly map 'id' to the reminder or clarify that 'delete' toggles between complete and delete. An agent might not know the semantics without inspecting 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 states a specific verb 'Mark' with a clear resource 'reminder' and an explicit alternative 'or delete it'. This clearly distinguishes it from sibling tools like add_reminder, as it is the only tool that acts on existing reminders to complete or delete them.

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?

No explicit when-to-use guidance is given. It is implied that this tool is for completing or deleting reminders, but there is no mention of alternatives or conditions (e.g., when to use delete vs. complete). The agent must infer from the name and description.

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