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

The readOnlyHint annotation already establishes this is a safe read, so the description's main added value is that results are account-scoped and their ids are consumed by trengo_update_contact. It discloses nothing about pagination behavior despite the page parameter, nor about result ordering or volume.

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 front-loaded sentence carries the core meaning, with the API endpoint appended as compact reference. No repetition of the title and nothing that fails to earn its place.

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 trivial read-only list tool with a fully documented single parameter and no output schema, the description plus annotation covers what an agent needs: what it returns (contact groups), that it is account-wide, and how the ids are used. Only return-field detail is left implicit.

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?

One parameter with 100% schema description coverage ('Page number (1-based). Omit for the first page.'), so the schema fully documents it. The description adds no pagination or page-size context beyond that, which is the baseline expectation when the schema does the heavy lifting.

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'), which clearly separates it from siblings like trengo_list_contacts, trengo_list_labels, and trengo_list_teams. Scope is implied (account-wide) but the description stops short of contrasting itself with the other list_* tools beyond the resource noun.

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?

Gives a concrete downstream usage: 'use their ids with trengo_update_contact', which tells the agent why and when to call this tool (to obtain group ids for a contact update). It lacks any when-not guidance or mention that other list tools exist, but the context is clear and actionable.

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