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

With annotations already marking the tool destructive, idempotent, and non-read-only, the description adds useful behavioral detail beyond them: the tool is a WRITE limited to one field, system fields are rejected, and custom field names must be sourced from cogmento_get_templates. It does not describe whether other fields remain unchanged or what errors look like, but that is a minor gap given annotation coverage.

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?

It is four compact sentences with the operative verb and scope front-loaded. Every sentence adds information: examples, template lookup, system-field restriction, and endpoint form, with no redundant repetition of schema details.

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 4-parameter mutation tool with no output schema, the description covers the essential call semantics: what is written, which fields are invalid, and where valid custom field names come from. It could be slightly more complete about side effects on untouched fields or permission requirements, but the annotations already carry the safety profile.

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 already 100%, so the baseline is 3. The description adds value beyond the schema by explaining where valid field names come from (cogmento_get_templates) and which field names are refused (id, acl, private, timestamps), which directly informs the field_name parameter.

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?

The description opens with a specific verb and scope: "WRITE: change a single field of a contact, company, deal, task or case". This clearly distinguishes it from create/get/list siblings and from broader record-level mutations, and it names concrete examples such as a deal's status or a contact's first_name.

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?

It gives a clear when-to-use context (single-field changes) and an explicit exclusion (“System fields (id, acl, private, timestamps) are refused”), plus a prerequisite for custom fields (“Custom field names come from cogmento_get_templates”). It does not explicitly route agents away from specialized siblings such as cogmento_set_deal_contact_stage, so it is strong but not fully alternative-aware.

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