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

Annotations already declare readOnlyHint=true, so the tool is known to be read-only. The description adds the instruction to 'read the names back', which implies the output is a list of chat names, but doesn't describe pagination, limit behavior, or error handling. Given the annotation coverage, the description provides marginal added context.

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 two sentences, front-loaded with the purpose and immediately followed by a usage trigger. Every word earns its place; there is no fluff or redundancy.

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 listing tool with readOnlyHint and no output schema, the description gives the core purpose and a clear usage condition. It doesn't explain the limit parameter or output format beyond 'names', but given the tool's simplicity and the annotation coverage, it is nearly complete. Minor gaps in parameter details prevent a 5.

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 50% – only authCode has a description, while limit is undocumented. The description does not mention either parameter, nor does it explain the effect of limit or how authCode should be used. With half the parameters lacking schema descriptions, the description fails to compensate for the gap.

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 states 'List open group chats' – a clear verb and resource. It doesn't explicitly name sibling tools like gc_focus or gc_history, but the scope (open chats) is distinct enough that an agent can infer the difference. Slight deduction for not explicitly differentiating from related gc tools.

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?

Provides a precise trigger: 'When the user says hey any group chats / any group chats — call this and read the names back.' This tells the agent exactly when to invoke the tool and what to do with the results. It doesn't mention alternatives or when not to use it, but the trigger is clear.

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