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

Annotations already flag destructiveHint=true and idempotentHint=true, but the description adds real context: it is a partial update since only supplied fields are sent, and it overwrites prior values for those fields. It does not state what happens to omitted fields (left untouched vs cleared) or any auth/permission needs, which keeps it below 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 'WRITE:' signal and the endpoint, with zero filler. Every clause carries information an agent needs.

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?

Annotations cover the safety profile and there is no output schema to explain, but for an 8-parameter destructive open-world mutation the description says nothing about the response, error behavior, or which contact_id form is valid beyond the schema. Adequate for the happy path only.

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 only 13%, so the description must compensate, and it partially does by explaining the patch-style semantics of the supplied fields. However it names none of the seven updatable fields (cell, email, phone, company, first_name, last_name, description), leaving field-level meaning entirely to property names.

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 (change fields of an existing contact), leads with a 'WRITE:' marker, and gives the endpoint PUT /contacts/{contact_id}. That cleanly separates it from farmbrite_create_contact and the read-only get/list siblings.

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 parenthetical 'only the fields you pass are sent' implies partial-update usage, so the agent can infer when this is appropriate versus a full create. But it never explicitly says when to use this over create_contact, nor any prerequisites such as needing an existing contact_id from a list/get call.

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