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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the scoping detail ('visible to the current principal'), which is useful behavioral context beyond the annotations. However, it doesn't disclose pagination behavior, ordering, or whether the result includes nested members, which would be relevant for a list 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?

The description is a single sentence with no wasted words. It front-loads the verb and resource, and the scoping qualifier is concise. Every word earns its place.

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 list operation with read-only annotations, the description is mostly adequate. However, with no output schema and no parameter descriptions, an agent might not know what the response looks like or how to use limit/starting_after for pagination. The description doesn't mention pagination or response format, which are common gaps for list tools. Given the simplicity of the tool, this is a minor gap, but it prevents a higher score.

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 0%, so the description carries no parameter information. The schema itself defines three parameters (limit, request_id, starting_after) with basic types and constraints but no descriptions. The tool description doesn't explain what these parameters mean or how they relate to the listing behavior. Since the schema provides minimal semantics and the description adds nothing about parameters, a 3 is appropriate – the parameters are simple and self-explanatory to some degree, but the description doesn't compensate for the 0% coverage.

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 'List Departments visible to the current principal' clearly states the verb (list) and resource (departments), and adds a scoping qualifier ('visible to the current principal') that distinguishes it from other department-related tools. It doesn't explicitly differentiate from sibling tools like yardstick_departments_read, but the verb+resource combination is clear enough.

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 description implies usage context: it lists departments visible to the current principal, which suggests it's the appropriate tool for enumerating departments the caller can access. However, it doesn't explicitly state when to use this over alternatives like yardstick_departments_read or yardstick_departments_create, nor does it mention any exclusions or prerequisites.

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