Find focus time

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

The annotations already declare readOnlyHint, openWorldHint, and idempotentHint. The description explicitly states 'Read-only' and explains the algorithm (working hours, lunch, existing items, buffer, longest block first). This adds detail beyond the annotations. However, the reference to `min_focus_block_minutes` (a non-existent parameter) creates a minor inconsistency in the behavioral description, preventing a perfect score.

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 well-structured with an introductory sentence, a detailed explanation, a read-only note, and a clean 'Args' section. It is not overly verbose, but the inclusion of the `min_focus_block_minutes` parameter (which is not part of the schema) introduces an unnecessary and confusing element that could have been omitted.

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 description provides context about the tool's behavior (longest block first, minimum block length) and the intended use case (finding deep work time). Since an output schema is available, it does not need to fully detail the return structure. The description is mostly complete, but the missing output format details and the `min_focus_block_minutes` inconsistency keep it from being fully comprehensive.

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?

The 'Args' section in the description provides clear, specific explanations for all five parameters: `time_min`, `time_max`, `hours_needed`, `calendar_ids`, and `account`. This goes well beyond the bare schema (which has no descriptions) and fully clarifies the meaning and expected format of each parameter.

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 purpose: it finds uninterrupted time blocks for deep work within a given window, considering working hours, lunch, existing events, and buffer. It also explicitly distinguishes itself as a read-only analysis tool, directing users to `block_focus_time` for actually blocking time. This makes the purpose specific and unambiguous.

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 gives some usage guidance by noting that it is read-only and that `block_focus_time` is the appropriate tool for actually defending time. However, it does not explicitly compare against other similar tools like `find_events` or `query_free_busy`, nor does it state when to prefer this tool over those. The mention of `min_focus_block_minutes` (which is not a parameter in the schema) adds slight confusion but does not significantly impair usage guidance.

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