Slack MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool performs a deletion (implying a destructive, irreversible mutation) but doesn't mention critical behavioral traits like required permissions, rate limits, whether it works only for the bot's own messages or any message, or what specific error conditions might occur. The return value description is vague ('Dictionary indicating success or error'), lacking detail on structure or common outcomes.

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 appropriately sized and front-loaded, with the core purpose in the first sentence. The Args and Returns sections are structured for clarity, though the return description could be more specific. There's minimal wasted text, but the formatting with quotes and indentation slightly reduces readability.

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 complexity (destructive operation with 2 parameters), lack of annotations, and presence of an output schema (though unspecified in detail), the description is moderately complete. It covers the basic purpose and parameters but lacks behavioral context like permissions or error handling. The output schema existence means return values don't need full explanation in the description, but more guidance on usage and risks would improve completeness.

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 semantics beyond the input schema, which has 0% description coverage. It explains that 'channel_id' identifies the channel containing the message and provides an example format ('C01234567'), and clarifies that 'timestamp' specifies which message to delete. This compensates well for the schema's lack of descriptions, though it doesn't detail the timestamp format (e.g., Unix time or Slack timestamp).

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 action ('Delete') and resource ('a message from a channel'), making the purpose immediately understandable. It distinguishes from siblings like 'update_message' or 'remove_reaction' by specifying deletion rather than modification or reaction removal. However, it doesn't explicitly differentiate from other destructive operations like 'archive_channel' beyond the resource scope.

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 appropriate permissions), when not to use it (e.g., for messages that shouldn't be deleted), or suggest alternatives like 'update_message' for editing instead of deleting. The agent must infer usage from the purpose alone.

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