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

Annotations already declare readOnlyHint=true, so the safety profile is covered by structured data and the bar is lower. The description adds the REST endpoint reference, which is useful orienting context, but says nothing about pagination, result limits, or required auth scope for a listing operation.

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 compact sentences, front-loaded with what is listed and followed by the filtering scope and API mapping. Nothing is redundant and nothing wastes space.

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 simple read-only list tool with zero required parameters, full schema coverage and no output schema, the description covers purpose, scope and API mapping adequately. Only minor gaps remain, such as whether the default return is filtered or complete and any result-size caveats.

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 100% and two of the three parameters carry enums with documented values, so the schema does the heavy lifting. The description only restates the filterable fields (type, role, status) already enumerated in the schema, adding no syntax or combination semantics beyond it.

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 gives a specific verb and resource ('List users of the tailnet') plus the scope of optional filtering by type, role or status, and even maps to the underlying REST endpoint. It is clearly distinguishable from tailscale_get_user (singular) and tailscale_list_devices, though it never names a sibling explicitly, which keeps it just short of a 5.

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 presence of filter parameters and the 'optionally filtered' phrasing implies when the tool is useful (enumerating the tailnet's user base with narrowing), but there is no explicit when-to-use guidance and no statement of when an alternative such as tailscale_get_user would be preferred. Usage is inferable rather than stated.

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