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

Adds substantial behavior beyond the annotations: PUT requires a read-then-write of current values, passing emails/phones/custom_fields REPLACES the existing lists (a real data-loss trap), and 'Nothing is sent to the person' clarifies external side effects. Annotations only say destructive/idempotent/not-readonly; the description explains why and how.

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 dense sentences plus an endpoint token; the critical warning (WRITE, list replacement) is front-loaded. Slightly redundant to repeat the replacement semantics per list and to append the raw 'PUT /contacts/{id}' path, but no sentence is wasted.

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 8-parameter mutation tool with full schema coverage, no output schema, and annotations covering the safety profile, the description closes the remaining gaps: read-modify-write mechanics, destructive list replacement, and absence of outbound messages. Nothing needed to call 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?

Schema description coverage is 100% and each array parameter already documents 'replaces the current list', so the description largely restates that. It adds no syntax, format, or edge-case meaning beyond the schema, so the baseline 3 is appropriate.

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?

Opens with "WRITE: change a contact's name, company, job title, emails, phones or custom fields" – a specific verb plus resource plus the exact mutable field set. The WRITE marker and 'change' clearly separate it from read siblings like helpwise_get_contact and helpwise_list_contacts.

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?

Usage is implied rather than stated: the WRITE label and field enumeration signal 'use this to modify an existing contact', but the description never explicitly contrasts with helpwise_create_contact or helpwise_get_contact, nor states prerequisites such as needing the contact to already exist. Adequate but with a clear routing gap.

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