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 mentions the tool lists conversations and returns a dictionary, but fails to describe critical behaviors: whether this requires authentication, any rate limits, pagination details (beyond the limit parameter), or what specific fields the dictionary contains. For a tool with zero annotation coverage, this leaves significant gaps in understanding how it operates.

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 appropriately sized: a brief purpose statement followed by dedicated sections for Args and Returns. Each sentence adds value, with no redundant information. Minor improvement could be made by integrating the purpose more seamlessly, but overall it's efficient and front-loaded.

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 low complexity (2 simple parameters) and the presence of an output schema (which handles return value documentation), the description is largely complete. It covers purpose, parameters, and return type adequately. The main gap is the lack of behavioral details (e.g., authentication needs), but this is partially mitigated by the output schema reducing the need to explain returns.

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 substantial value beyond the input schema, which has 0% description coverage. It clearly explains both parameters: 'types' as comma-separated conversation types with options ('im' for 1:1 DMs, 'mpim' for group DMs) and default, and 'limit' as maximum number to return with default. This fully compensates for the schema's lack of documentation, making parameter usage clear.

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 ('direct message and group DM conversations'), making the purpose immediately understandable. It distinguishes this tool from siblings like list_channels (which handles public/private channels) and list_users (which handles user listings). However, it doesn't explicitly contrast with get_dm_history (which retrieves message history within DMs), leaving some sibling differentiation incomplete.

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 context through the mention of 'direct message and group DM conversations,' suggesting this is for listing conversation metadata rather than message content (unlike get_dm_history). However, it lacks explicit guidance on when to use this versus alternatives like open_dm (for initiating DMs) or send_dm (for messaging), and provides no exclusion criteria or prerequisites.

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