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

Annotations already cover readOnly and idempotent hints (both false). The description adds 'Accepts flexible time formats,' but that is parameter-related, not behavioral. It does not disclose side effects, validation rules, or requirements like an existing baby.

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 with no wasted words. The purpose is front-loaded, and the second sentence is a brief but acceptable note on flexibility. Efficient and clear.

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?

The tool has annotations, an output schema, and fully documented parameters, so the description can be minimal. However, it lacks usage alternatives and any caveats, making it adequate but not thorough for a complete picture.

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% with detailed format lists for start and end. The description's mention of 'flexible time formats' is redundant with the schema, so it adds no new meaning. Baseline 3 applies.

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 ('Log') and resource ('sleep session for a baby'), clearly distinguishing it from sibling create_* tools for diary, feed, and nappy. This is immediately actionable.

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 guidance is provided on when to use this tool versus sibling create_* tools, nor are prerequisites or exclusions mentioned. The purpose is self-evident but no explicit usage direction is given.

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