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

The readOnlyHint=true annotation already establishes the safe-read profile, and the description adds the underlying endpoint (GET /contact_groups) plus the fact that returned ids drive updates. It says nothing about pagination behavior or result volume, which matters for a paged list endpoint.

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?

A single compact sentence with the core action front-loaded, followed by the downstream-use hint and the API endpoint. No filler.

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 read-only list tool with an annotation covering safety, a fully documented schema, and no output schema, the description is nearly sufficient. The only missing nicety is guidance on paginating through large group lists.

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?

Only one optional parameter and schema_description_coverage is 100%, so the schema already documents the 1-based page number. The description adds no syntax or defaulting detail beyond that, making the baseline 3 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 ('List the contact groups in the account'), and ties the result to a downstream action by naming trengo_update_contact, which distinguishes it from the other trengo_list_* siblings that cover labels, teams, users, and custom fields.

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 clause 'use their ids with trengo_update_contact' tells the agent when this tool is worth calling and what it feeds into. There is no explicit when-not guidance or exclusion, but the intended workflow context is clear.

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