List contact groups

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is clear. The description adds that it returns a list of all contact groups, but it does not disclose additional behavioral details such as pagination, rate limits, or response shape. This is acceptable for a simple read-only tool but adds little beyond the annotations.

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?

The description is short and front-loaded with the core action. The second sentence partially repeats 'returns a list' but adds useful context about contact groups being for organizing contacts, so it is not wasted. Overall it is concise and easy to scan.

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?

With no parameters, a read-only annotation, and a simple listing purpose, the description is largely complete for invoking the tool correctly. Minor gaps like pagination or output format are not addressed, but the low complexity and zero-parameter surface make this a minor issue.

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?

The tool has zero parameters and 100% schema description coverage, so there is nothing for the description to explain at the parameter level. Per the baseline for zero-parameter tools, a score of 4 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?

The description clearly states the operation and resource: 'Get a list of all contact groups.' It is distinguishable from sibling reach_* list tools by naming the specific resource type, though it does not explicitly contrast itself with reach_listContactsV1, reach_listSegmentsV1, or reach_listContactFieldsV1.

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?

There is no guidance about when to use this tool versus alternatives. The sibling list includes several similar reach_* list tools, and the description does not explain why an agent should choose contact groups over contacts, segments, or fields. The phrase 'can be used to organize contacts' is only domain context, not a usage guideline.

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