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

Annotations only supply destructiveHint=true; the description adds two genuinely behavioral facts: this is a partial (merge) update, and list-valued fields REPLACE rather than append — real data-loss context that the annotation alone does not convey. It also cites the underlying REST endpoint (PATCH /v1/companies/{id}) for provenance. It omits permissions/auth needs and error behavior, so not a 5.

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 short sentences, front-loaded with the core action followed by the two behaviors that matter most, then the API reference. No filler or repetition.

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 14-parameter mutation tool with no output schema, the description covers the critical semantics an agent needs (partial update, list replacement). It stops short of naming auth/permission requirements or what happens when the id does not exist, minor gaps for an otherwise tight definition.

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% across all 14 parameters, so the schema already documents each field, including the per-field 'Replace the company's ...' notes. The description's blanket rule about list replacement restates what the schema says per property, so it adds little beyond the baseline.

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?

States a specific verb (update) and resource (company) with the qualifier 'existing', which cleanly separates it from folk_create_company and, by resource, from folk_update_person. It never names a sibling directly, but the scope is unambiguous from the description alone.

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 explains the update semantic ('only provided fields are changed') but gives no when-to-use framing, no prerequisites, and no exclusions or alternative tools. Usage is implied by the name rather than stated.

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