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

Annotations only provide destructiveHint=true; the description adds real behavioral context on top: the 'MUTATES' framing, form-encoded POST body, the two-step affiliation caveat, and the { meta, response } return shape. It does not cover auth/permission requirements or failure modes, 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?

Every clause earns its place: mutation flag first, endpoint second, the non-obvious affiliation caveat third, return shape last. No filler and nothing buried.

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 states the return envelope, and the schema fully documents inputs including the nested fields object. For a create tool with only destructiveHint, the agent has enough to invoke it correctly.

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%, so all six parameters including the nested 'fields' bag are already documented in the schema. The description adds no per-parameter meaning, which is the expected baseline when the schema carries the load.

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+resource: 'creates a new contact (a person)', disambiguating from the sibling create_company. It also pins the backing endpoint (POST /api/v0/contacts), so an agent knows exactly what operation this is.

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?

No explicit routing guidance among siblings (e.g., when to prefer create_contact over accelo_request or create_company). It does supply a useful workflow constraint — company affiliation must be attached afterward via a separate affiliations call — which is implied usage context rather than a full when/when-not rule.

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