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

Annotations already declare readOnlyHint=false and destructiveHint=false, so mutation is known. The description adds the auth requirement for employee_id and the important constraint that project_ids must come from timelog_get_loggable_projects, giving the agent behavioral context beyond the annotations alone.

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?

Three sentences, front-loaded with the core action, then conditional workflow guidance. No redundant phrases; every sentence adds a distinct piece of information.

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?

With 10 parameters and no output schema, the description covers the critical decisions: who, what project, and activity-type usage. It does not cover all edge cases such as billable time without a project or what the API returns on success, but the schema and annotations handle most remaining details.

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 50%, so the description compensates by explaining project_id (must be a loggable project) and activity_type_id/activity_type_name (for non-billable non-project time). It also reinforces employee_id's permission requirement. It does not add semantics for note/hours/is_billable, but those are self-explanatory or covered by schema defaults/types.

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 and resource: 'Log a time entry' and distinguishes self vs. employee and project vs. non-project time. It clearly identifies this as the create-time-entry tool rather than timelog_update_entry or timelog_add_expense.

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?

It gives explicit conditional usage: for project time, first call timelog_get_loggable_projects and only pass a returned project_id; for non-billable time without a project, use activity_type_id/activity_type_name. It implies when to use this tool well, but does not explicitly state when not to use it or name an alternative for similar actions.

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