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

With only destructiveHint=true in annotations, the description adds real context: it discloses that contact_group_ids overwrites rather than appends, which explains the destructive flag, and that updates are partial ('and/or'). It omits auth requirements and error behavior, keeping it out of the top band.

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 tight, front-loaded sentences with the overwrite warning in caps where it matters most. The trailing 'Trengo: PUT /contacts/{id}' is minor filler that an agent already has from the tool identity, but nothing else 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 a simple 3-parameter update with full schema coverage and no output schema, the description covers what matters: what can change and the destructive group semantics. Only prerequisites and failure behavior are unaddressed, which are small gaps at this complexity.

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 coverage is 100%, so all three parameters are already documented in the schema, including the group-replacement note. The description largely restates that verbatim, adding only emphasis and the mutual optionality of name/contact_group_ids; 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?

States a specific verb and resource ('Rename a contact and/or set the contact groups it belongs to'), naming the exact fields the tool can change. This clearly separates it from siblings like trengo_create_contact and trengo_get_contact without opening any schema.

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 implicit: the 'and/or' phrasing tells the agent at least one of the two updateable fields is expected, and the REPLACES warning signals destructive group reassignment. However, it never states when to reach for this tool over create/get, nor any prerequisite such as the contact having to exist.

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