Slack: Channel History

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description's 'Read' aligns well. However, the description adds no further behavioral context such as pagination, rate limits, or message format. With annotations covering the safety profile, a 3 is appropriate.

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 a single sentence of 6 words, extremely concise and to the point. It front-loads the core purpose without waste. However, it could benefit from slightly more context without becoming verbose, hence not a 5.

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 simple nature of the tool (3 params, no output schema, read-only), the description is minimally adequate but lacks information about what the output contains (e.g., list of messages) and how it differs from similar tools like 'chat_history'. With no output schema, more detail 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 input schema has 100% description coverage, meaning each parameter already has a description. The tool description does not add additional meaning beyond the schema, so baseline 3 is correct. The limit parameter's default/max in schema is already documented.

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 uses a specific verb 'Read' and resource 'recent messages from a Slack channel', clearly stating the tool's function. However, it does not explicitly distinguish this from sibling tools like 'chat_history' or other Slack tools that might also read messages, so it loses a point for lack of differentiation.

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. No mention of scenarios, prerequisites, or situations where another tool would be more appropriate, leaving the agent without decision context.

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