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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds real behavioral context beyond that: the result is ordered newest-first and includes not just entries but also the running timer and per-customer totals, plus the default 30-day window.

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?

Two dense sentences with the core behavior and response shape front-loaded; no filler and every clause carries information the agent needs.

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 7-parameter read tool with no output schema, the description tells the agent what comes back (entries, running timer, per-customer totals) and the default window, which is most of what is needed. Minor gaps remain around pagination and the undocumented filter parameters.

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 only 57%; companyId, contactId, and status have no schema descriptions. The description supplies the meaning of the "unbilled" status value and the default date window, but leaves "billed" and the company/contact filters unexplained, so it only partially compensates.

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?

Names a specific verb and resource ("List time entries") and adds scope detail: newest-first ordering, inclusion of the running timer, and per-customer totals. It does not name the sibling time_manage, so the agent must infer that this is the read-only counterpart rather than being told explicitly.

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 default last-30-days window and the definition of status "unbilled" give useful context for when this tool's output applies. However, there is no explicit statement about when to use this versus time_manage or how to widen the range, so usage is implied rather than guided.

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