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

Annotations already cover the read-only, idempotent, closed-world safety profile, and the description adds what they cannot: authorization requirements, the plan gate, and the exact failure mode on Free ('a plan-limit message'). It omits pagination or result-size behavior, which is the one behavioral gap left.

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 tight sentences, front-loaded with what the tool returns, then the permission rule, then the plan restriction. Every clause carries distinct information and nothing is repeated from the 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?

With no output schema, the definition still conveys shape ('a timesheet'), the required authorization, and the plan precondition, which is nearly everything an agent needs to call it correctly. A note on result volume or ordering would close the remaining gap.

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 100%, so from/to formats and the userId default are already documented in structured fields. The description only adds the constraint that the from–to window is capped at three months, useful but marginal beyond the schema.

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 and resource ('a person's time entries between two days (a timesheet)') and pins the scope with a hard window of at most three months. That is enough to separate it from log_time, update_time_entry, and get_task_time without opening another schema.

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 clear applicability conditions: defaults to the caller, another person's entries require Administrator or ProjectManager, and the workspace must be on the Pro plan. It stops short of naming an explicit alternative for cases like per-task time breakdowns, so it is strong context rather than full routing.

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