Slack MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states the action ('Remove') which implies mutation, but doesn't mention permission requirements, rate limits, whether the operation is reversible, or what specific success/error responses look like. The return value description is vague ('Dictionary indicating success or error').

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 well-structured with a clear purpose statement followed by Args and Returns sections. Each sentence earns its place by providing essential information. However, the 'Returns' section could be more specific about the dictionary structure rather than just stating 'success or error'.

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 mutation tool with 3 parameters and no annotations, the description covers the basic operation and parameters adequately. However, it lacks important contextual information about permissions, error conditions, and behavioral constraints. The presence of an output schema helps, but the description's return value explanation is too vague to fully compensate for the missing annotation coverage.

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?

With 0% schema description coverage (titles only provide parameter names), the description adds crucial semantic information for all 3 parameters. It explains what each parameter represents with concrete examples: channel_id identifies the channel, timestamp identifies the message, and emoji specifies which reaction to remove (with format examples like 'thumbsup' without colons).

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 ('Remove an emoji reaction from a message') with the exact resource involved. It distinguishes itself from sibling tools like 'add_reaction' by specifying removal rather than addition, and from other message-related tools like 'delete_message' by focusing specifically on reactions.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing to have added the reaction first), when not to use it, or how it differs from similar operations like 'delete_message' or 'add_reaction'. The agent must infer usage context from the tool name alone.

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