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

readOnlyHint=true already tells the agent this is a safe read. The remaining content — cursor pagination, verbatim filter/order_by, hydration depth, and the REST mapping GET /rest/companies — is almost entirely restated from the parameter schema, so the description adds little behavioral context beyond it (no rate limits, no response shape).

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: the primary purpose is front-loaded, the capability list follows, and there is no filler. Every clause carries 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?

For a low-complexity, zero-required-parameter list tool with fully documented parameters and a readOnly annotation, this is nearly sufficient — the cursor pagination model is hinted at and the REST endpoint disclosed. It is slightly short of complete because no output schema exists, yet nothing describes the returned payload (data array, pageInfo) that pagination depends on.

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 the schema already documents comparators, cursor semantics, the 1-60 limit cap, and depth values in more detail than the description. The description's mention of filter/order_by/depth therefore adds no meaning beyond the schema, which makes the baseline 3 correct.

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?

"List/filter companies" states a specific verb and resource, and the name/verb pair makes it immediately distinct from twenty_get_company (single record) and twenty_create_company (write). It stops short of naming any sibling or contrasting scope, so it is clear but not fully differentiated in the text itself.

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 enumerates capabilities (cursor pagination, raw filter/order_by, relation depth) but never states when to reach for this tool versus twenty_get_company or twenty_list_people, nor any prerequisites. Usage is only implied by the verb "List/filter".

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