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

Annotations indicate idempotent (safe to retry) and non-destructive. The description adds that domains are monitored continuously and trigger email alerts, providing complete behavioral context beyond 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?

Three sentences: action, monitoring behavior, prerequisites/limits. No extraneous information; front-loaded and efficient.

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 tool with one parameter and no output schema, the description covers purpose, behavior, constraints, and prerequisites completely.

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% with a clear description and example. The tool description adds the constraint of 100 total watched domains, which is not in the schema, enhancing parameter understanding.

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 ('Add one or more domains to your snooze watchlist') and the resource (domains). It distinguishes from sibling tools like check_domains and unwatch_domains by specifying monitoring and email alerts.

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 constraints ('Requires signing in', 'Up to 25 domains per call (100 total)') but does not explicitly contrast with alternatives. However, the context is adequate for selecting the tool.

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