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

With no annotations provided, the description fully discloses behavior: it explains the effects of each 'confirmed' value, notes that 'minutes' are acknowledged but not stored, mentions the default date, and states the OAuth scope requirement. This goes beyond the schema and gives the agent a clear picture of side effects and permissions.

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 sentences, front-loaded with the primary purpose, then covers values, defaults, and auth. Every sentence adds necessary information without waste.

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 write operation with full schema coverage and no output schema, the description is complete. It explains purpose, parameter semantics, default behavior, and auth requirements. No significant gaps remain.

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 description doesn't need to add much. It does restate the default for 'confirmed' (true) and the non-storage of 'minutes', but these are already in the schema. The description adds no new parameter semantics beyond what structured schema provides, warranting the baseline score.

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 tool's function: 'Sets a day's answer in the signed-in user's history calendar.' The verb 'Sets' and resource 'day's answer in history calendar' are specific. It distinguishes from siblings (e.g., get_my_history reads, update_my_profile modifies profile) by targeting the sun session log specifically.

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 context for when to use this tool: to log a day's sun session answer. It explains the three allowed values and defaults. It does not explicitly name alternative tools or exclusion criteria, but the purpose is unambiguous enough for an agent to infer appropriate usage.

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