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

Annotations already flag readOnly=false, destructive=true, idempotent=false and openWorld=true, so the bar is lower; the description still adds real value by noting that entries spanning midnight are split into two, that the new entry's id is returned, and by naming the underlying API call. It does not warn about duplicate creation despite idempotentHint=false.

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 write intent and the example are front-loaded, followed by the required inputs and optional inputs in a logical order. It is dense but nearly every clause carries information; the redundant "Teamleader: timeTracking.add" trailer earns little.

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 9-parameter creation tool with no output schema, the description covers the required input combination, optional inputs, a notable side effect (midnight split) and the return value (new entry's id). That is enough for an agent to call it correctly without further documentation.

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 78%, giving a baseline of 3, and the description improves on it by stating the mutual exclusivity of duration_minutes and ended_at, the subject (customer/ticket/task) pairing, and the invoiceable flag. It still leaves user_id, work_type_id and the subject_type enum semantics to 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?

Opens with a specific verb+resource ("WRITE: record time spent") plus a concrete example, and the WRITE marker distinguishes it from the read-only sibling teamleader_list_time_tracking. An agent can identify it without opening the 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?

"Give started_at plus duration_minutes or ended_at" spells out the required invocation combination, and it lists what is optional (work type, description, subject, invoiceable). It gives clear context for how to call it, though it never explicitly says when to prefer this over teamleader_list_time_tracking or what to do if a duplicate already exists.

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