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

Annotations already declare readOnlyHint, destructiveHint=false, and openWorldHint, so safety is covered. The description adds genuinely useful context beyond that: the exact field set returned, an explicit privacy exclusion list (birth dates, addresses, phones, contractor pay rates), and the underlying GET /users endpoint.

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 compact sentences: returned fields first, then exclusions, then filtering and endpoint. Dense and front-loaded with no filler, though the endpoint token is mildly redundant.

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 description compensates by enumerating returned and withheld fields, which is exactly what an agent needs for a list tool. Pagination is covered by the schema's top/skip/next_skip documentation, so nothing critical is missing.

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 description coverage is 86%, so the schema already documents id, top, skip, sort, descending, and include_custom_fields. The description only restates that status and id act as filters and adds nothing about syntax, enum values, or pagination interaction beyond what the schema provides. Baseline 3 applies.

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 ('List the firm's users') and enumerates the returned fields plus the ones deliberately withheld, so the agent knows exactly what comes back. It distinguishes itself de facto by resource from siblings like bill4time_list_clients or bill4time_list_invoices, but never names an alternative 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?

'Filter by status or id' hints at when to narrow the query, and the exclusion notes tell the agent when not to expect certain data. However, there is no explicit when-to-use framing and no routing against siblings, so usage is only implied.

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