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

Annotations provide only destructiveHint=true, so the description carries most of the burden for a mutation tool. It tells the agent the record is created via POST /Contacts but omits auth/permission requirements, whether duplicates are merged or rejected, what the response returns, and what happens to unrelated fields — significant omissions for a create.

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 short sentences, front-loaded with the core action and the required-field constraint, with no filler. It is efficient, though the trailing endpoint note is of marginal value to an agent.

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 an 18-parameter mutation with no output schema and only a destructiveHint annotation, the description is far too thin — it explains nothing about return values, error conditions, or how the many optional fields interact. An agent calling this correctly must rely almost entirely on the schema.

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 72%, above the baseline threshold, so the schema documents most parameters itself. The description only repeats that first_name is required, adding no format, validation, or usage detail beyond what the schema already states.

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 ('Create a contact') and even names the underlying endpoint (POST /Contacts), which pins the action unambiguously. It does not, however, distinguish itself from siblings like insightly_create_lead or insightly_update_contact, so an agent must infer from the name 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?

No guidance on when to create a contact versus creating a lead or updating an existing contact, and no prerequisites or deduplication caveats. The only condition given is that first_name is required, which is already enforced by the schema.

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