list_joined_channels

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description adds value by explaining the default channel types and how to include DMs. This matches the read-only nature and does not contradict the annotations. The extra context about types improves transparency beyond the annotation flags.

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?

Two sentences, no redundant phrasing. The primary purpose is front-loaded, and the parameter guidance is integrated efficiently in a single follow-up sentence. Every word earns 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 simple listing tool with an output schema and all-optional parameters, the description covers the essential usage: what it lists, the default scope, and how to broaden it. It omits clarification on limit and exclude_archived, but these are minor given the tool's simplicity and the output schema presence. Complete enough for typical invocations.

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 0%, so the description must compensate. It only explains the 'types' parameter with a concrete example, leaving 'limit' and 'exclude_archived' undocumented. While their names are somewhat self-explanatory, the description does not fully mitigate the schema gap, especially for agents that rely on the description for all parameter meaning.

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 action ('List channels') with a precise scope (channels the authenticated user is a member of), clearly distinguishing it from sibling tools like get_channel_history (which fetches message history) or get_channel_id_by_name (which resolves IDs). The purpose is unambiguous.

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?

It provides clear context on default behavior (public and private channels only) and how to extend to DMs via the types parameter, which helps agents decide when to call this tool. However, it does not explicitly mention alternative tools or give 'when not to use' guidance, so it stops short of a full 5.

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