Time spent

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

Annotations already indicate read-only, idempotent behavior. The description adds value by disclosing that totals are computed server-side by Timely and that day buckets follow the account's timezone. This provides clarity beyond the 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?

The description is concise, containing a few clear sentences. It front-loads the purpose and critical details without unnecessary words. The informal lead phrase 'Where did my time go?' adds personality but is still 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?

Given the tool's moderate complexity (3 params, output schema present), the description covers the main aspects: date range, grouping, timezone behavior, and server-side computation. It provides sufficient context for an agent to use the tool effectively.

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 0%, so the description should compensate. It mentions the date range format (YYYY-MM-DD) and the group_by options, but does not elaborate on the meaning of 'since' and 'until' beyond the schema. Some value added but incomplete.

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 computes server-side rollups for time spent, grouped by project/client/label/day, with billable split. It distinguishes from siblings by focusing on aggregated rollups rather than detailed logs or overviews.

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 implies usage for aggregated time data, mentioning server-side rollups and grouping options. However, it does not explicitly state when to use this tool over siblings like work_log or projects_overview, leaving the agent to infer based on the 'rollup' nature.

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