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

readOnlyHint already covers safety, and the description adds genuinely new behavioral context: an authorization prerequisite ('key whose user may see everyone's time tracking') and pagination semantics with next_offset. It stops short of describing page-size defaults or ordering behavior, but the critical access constraint is disclosed.

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?

Four short sentences, front-loaded with what is returned and the cross-employee scope, then paging, then the running-timer toggle and the permission requirement. Every sentence carries distinct information, including the field list which substitutes for a missing output schema.

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 10-parameter, filter-heavy list tool with no output schema, the description covers return shape, paging, default period, the running-timer special case and the permission gate. Gaps are minor: the free-text 'search' parameter and the sort/order interplay are left entirely to the schema.

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 90%, so the schema already documents period, working_now, dates, paging and sorting. The description restates working_now and the period range without adding new syntax or constraints, so it lands at the baseline for well-documented schemas.

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?

States a specific verb (List) and resource (time tracking entries) plus the scope that matters most: across all employees, with the returned fields (start, end, duration, tags) named inline. No sibling tool lists time tracking entries, so scope language is enough to place it unambiguously in the toolset.

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?

Gives concrete selection guidance inside the tool: 'working_now=true lists only running timers', 'Paged: use next_offset to continue', and period-with-default vs explicit date range. It does not name a sibling alternative or state when not to use it (e.g. vs. calendar/report tools), which keeps it below a 5.

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