list_channels

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

No annotations are provided, so the description must disclose behavioral traits. It explicitly states 'Read-only' and warns that the sidebar is virtualized, meaning only currently-rendered entries appear and collapsed sections may be omitted. This adds important behavioral context beyond a simple list operation.

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 extremely concise with two sentences. It front-loads the primary purpose and provides the key caveat about virtualization. Every sentence adds value with no 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 tool with zero parameters and an output schema (so return values don't need description), the description covers the essential points: what it lists, read-only behavior, and the important limitation of virtualized sidebar rendering. This is complete for the tool's complexity.

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?

There are no parameters, so the baseline is 4. The description does not need to add parameter information because none exist. The schema coverage is 100% automatically.

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 'List the channels and DMs visible in your Slack sidebar.' This is a specific verb+resource combination and distinguishes the tool from its siblings (check_login, login, read_messages, read_thread) which do not perform listing of channels.

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?

No guidelines are provided for when to use this tool versus alternatives. The description does not mention when not to use it or suggest other tools for different scenarios, leaving the agent without context on selection.

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