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

readOnlyHint=true already establishes this as a safe read, so the bar is low, and the description adds genuine value by naming the underlying Platform API endpoint and the return envelope ({ channels[], next }). It adds no auth, rate-limit, or filtering behavior context, but the annotation/return-shape disclosure is solid for a read tool.

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?

Three short sentences with zero filler: purpose first, endpoint second, return shape third. Everything is front-loaded and nothing needs to be trimmed.

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 output schema, the description compensates by declaring the return shape (channels[] + pagination next). For a 9-parameter paginated list tool this is nearly sufficient; only the relationship to sibling listing tools is left unaddressed.

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 100% and all nine parameters (limit, order, token, hidden_mode, public_mode, show_member, custom_types, distinct_mode) are documented in the schema, so the baseline of 3 applies. The description adds nothing about parameter semantics beyond embedding user_id in the endpoint path.

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 a specific verb and resource ('List the group channels') and scopes it to 'a given user belongs to', which is the key differentiator from the sibling sendbird_list_group_channels. It stops short of naming that sibling explicitly, so an agent must still infer the split.

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 only implied by the phrase 'a given user belongs to'; there is no explicit statement of when to choose this over sendbird_list_group_channels or sendbird_list_group_channel_members. No prerequisites or exclusions are given.

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