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

With no annotations provided, the description carries the burden of behavioral disclosure. It goes beyond the obvious 'list' operation by revealing that the API caps the response server-side and that pagination params are advisory until the cap is lifted — a non-obvious behavior that affects invocation. It doesn't cover every behavioral aspect, but the most important caveat is disclosed.

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 sentences with no filler; the core action is front-loaded, use cases follow, and the important caveat is placed at the end. Every sentence earns its place and the structure is easy to scan.

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 tool with fully documented parameters and no output schema, the description covers the essential call context: what it lists, why to use it, and the pagination caveat. It is slightly less complete than a definition with annotations that explicitly signal safety and read-only behavior, but no critical information for invoking it correctly 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?

The schema already covers 100% of the parameters, so the baseline is 3. The description adds value by explaining that limit and offset are advisory because of the server-side cap, which meaningfully changes how an agent should interpret pagination parameters.

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 opens with a specific verb+resource statement, "List the user's companies," which clearly identifies the operation and scope. It further contextualizes the purpose with concrete use cases (linking a contact, summarizing CRM accounts), which distinguishes it from siblings like companies_get or companies_create.

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 gives explicit use cases: find a company before linking a contact, or summarize accounts. It does not, however, state when not to use this tool or mention alternative tools like companies_get for retrieving a single company's detailed record, so it stops short of a 5.

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