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 successfully explains authentication requirements (User Token vs bot tokens), which is crucial behavioral context. However, it doesn't mention rate limits, pagination behavior, or error conditions that would be helpful for an agent.

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 clear sections (purpose, note, args, returns) and every sentence adds value. It could be slightly more concise in the query explanation, but overall it's efficiently organized with no wasted text.

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 (5 parameters, authentication requirements, search functionality) and the presence of an output schema (so return values don't need explanation), the description is complete. It covers purpose, authentication, all parameters with semantics, and references the return structure appropriately.

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?

Despite 0% schema description coverage, the description provides comprehensive parameter documentation. It explains the query parameter with examples and Slack-specific modifiers, clarifies sort/sort_dir options and defaults, specifies count range constraints, and lists types options. This fully compensates for the schema coverage gap.

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 ('Search files') and resource ('across the Slack workspace'), distinguishing it from sibling tools like search_messages and search_all. It provides a complete verb+resource+scope statement that leaves no ambiguity about what this tool does.

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 explicitly states when to use this tool ('Search files across the Slack workspace') and provides critical context about token requirements ('Requires a User Token... not available with bot tokens'). It distinguishes this from other search tools by specifying it's for files specifically, not messages or general content.

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