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 mentions the return format ('Dictionary containing list of users with their profiles'), which is helpful, but lacks critical details: it doesn't specify whether this is a read-only operation, if there are rate limits, authentication requirements, pagination behavior (beyond the 'limit' parameter), or how it handles large workspaces. For a tool with no annotation coverage, this leaves significant gaps in understanding its behavior.

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 and front-loaded with the core purpose in the first sentence. The Args and Returns sections are clearly formatted, making it easy to parse. Every sentence adds value: the purpose statement, parameter explanations, and return format description are all necessary and efficiently presented.

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 (2 parameters, no annotations, but with an output schema), the description is partially complete. It covers the purpose and parameters adequately, and the output schema likely details the return structure, so explaining return values isn't needed. However, it lacks behavioral context (e.g., permissions, rate limits) and usage guidelines, which are important for a tool that lists all users in a workspace.

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 beyond the input schema, which has 0% description coverage. It explains that 'limit' is the 'Maximum number of users to return (1-1000)' with a default, and 'include_locale' controls whether to 'Include locale information for users' with a default. This clarifies the purpose and constraints of each parameter, compensating well for the schema's lack of descriptions.

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 verb ('List') and resource ('all users in the Slack workspace'), making the purpose immediately understandable. However, it doesn't explicitly differentiate this tool from sibling tools like 'get_user_info', 'lookup_user_by_email', or 'get_user_profile', which also retrieve user information but with different scopes or filters.

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 scenarios where this bulk listing is preferred over targeted lookups (e.g., 'get_user_info' for a specific user) or how it relates to other user-related tools like 'get_user_profile'. There's no context about prerequisites, such as required permissions or workspace access.

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