Find gaps

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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so safety is covered. The description adds the concrete detection threshold (20+ minutes) and the anchoring boundaries (between first and last session of the day), which is genuinely useful behavioral context, but it says nothing about the shape of the returned data.

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 definition of a gap. Tight and waste-free, though the second sentence is a behavioral instruction rather than descriptive content.

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 single-parameter, read-only query with full schema coverage and no output schema, the definition supplies the key semantics (what counts as a gap). It could go slightly further on what the call returns, but the essentials an agent needs are present.

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% and the 'date' parameter is fully documented in the schema ('YYYY-MM-DD in the user's timezone'). The description's 'of a day' only loosely corroborates that the date scopes to a single day, adding little beyond the schema baseline of 3.

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?

Names a specific resource ('gaps') and defines it precisely as 'untimed stretches of 20+ minutes between the first and last session of a day'. No sibling tool competes with this concept, so the agent can identify it readily, though it is phrased as a noun fragment rather than a verb+resource statement.

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 trailing 'Ask the user what happened there' implies a follow-up workflow, giving some sense of intended use. However, it never says when to call this tool versus alternatives (e.g. summarize_day), nor any prerequisite or exclusion; usage is only implied.

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