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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the 'accessible to the partner API key' qualifier, which is useful context about data scope, but it does not disclose pagination behavior, return format, or ordering, which are 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 short sentence with no redundancy. It is appropriately concise for a simple list operation, though it might benefit from a bit more operational detail.

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?

Given the tool's simplicity (only 2 params, no output schema) and that annotations cover safety, the description is minimally adequate. However, it omits pagination semantics and any mention of the response structure, which could leave agents uncertain about how to use the pagination parameters effectively.

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?

The schema has two parameters (page, size) with no descriptions (coverage 0%). The description does not mention either parameter, so it fails to compensate for the missing schema documentation. Agents have no guidance on whether they are optional, their range, or their effect on results.

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 clearly states the verb 'List' and the resource 'companies', and adds the scope 'accessible to the partner API key', which distinguishes it from other list tools and clarifies accessibility constraints. This is specific and unambiguous, and it differentiates from get_company or other list endpoints by resource.

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 for enumerating companies but does not explicitly contrast with alternatives like get_company or list_jobs. No exclusions or when-not-to-use guidance is provided, leaving the agent to infer from the resource name alone.

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