Slack MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the action ('Leave a Slack channel') and mentions a return type ('Dictionary indicating success or error'), but lacks details on permissions needed, whether the action is reversible, rate limits, or what specific success/error responses entail. This is a significant gap for a mutation 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?

The description is front-loaded with the core purpose in the first sentence, followed by structured Args and Returns sections. Each sentence earns its place by providing essential information without redundancy, making it highly efficient and well-organized.

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?

Given the tool's moderate complexity (a mutation with one parameter) and the presence of an output schema (which covers return values), the description is adequate but incomplete. It lacks behavioral details like permissions or reversibility, which are crucial for safe usage, though the output schema reduces the need to explain return values.

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 description adds meaningful context for the single parameter 'channel_id' by explaining it's 'The ID of the channel to leave' and providing an example ('e.g., "C01234567"'), which compensates for the 0% schema description coverage. Since there are no other parameters, this is sufficient for clarity.

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 specific action ('Leave a Slack channel') with the resource ('channel'), distinguishing it from siblings like 'join_channel' or 'archive_channel'. It uses a precise verb that directly matches the tool's name without being tautological.

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?

The description implies usage by specifying the action and resource, but does not explicitly state when to use this tool versus alternatives (e.g., 'archive_channel' for closing channels or 'join_channel' for the opposite action). It provides basic context but lacks guidance on prerequisites or exclusions.

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