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

Annotations already mark the tool as read-only (readOnlyHint: true). The description adds the behavioral context that the companies are those 'this signed-in account can bind a registration to' and explains the owner field for distinguishing duplicate names. No side effects are mentioned, but they are not needed given the read-only annotation and the tool's listing nature.

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, well-structured sentence. It front-loads the action and resource, then provides necessary details (output fields, duplicate handling) and a usage hint, with no redundant information.

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?

Even without an output schema, the description lists the returned fields (companyId, display name, owner) and explains their purpose. It also places the tool in a workflow with claim_company and whoami, making it clear when and why to use it. This provides complete context for an agent.

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 tool has zero parameters, so schema coverage is effectively 100%. Per the rubric, high schema coverage yields a baseline of 3; the description does not need to elaborate on inputs since there are none.

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 action ('List'), the resource ('companies'), and the scope ('available to this account'). It also explains the output fields and references sibling tools (claim_company, whoami) for context, making its purpose unambiguous and distinct from other tools.

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?

Explicitly provides a usage scenario: 'Use together with connections_claim_company when connections_whoami reports company:null.' This gives clear when-to-use guidance and indicates the expected workflow, leaving no ambiguity about when to invoke this tool.

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