slack_post_message

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

With no annotations, the description provides some behavioral context: messages are posted under the bot's identity, and text supports Slack mrkdwn. However, it does not disclose permissions requirements, rate limits, or error handling.

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 brief and front-loaded with the purpose. Three sentences cover the core action and parameter details without any extraneous information.

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?

While the output schema exists (not described here), the description misses contextual details like authentication requirements, channel membership prerequisites, or error scenarios. Also lacks comparison to sibling tools.

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?

Schema coverage is 0%, but the description adds detailed semantics: channel format (Cxxx, #channel, Uxxx), text content (mrkdwn supported), and thread_ts usage (omit for top-level). This significantly aids correct parameter usage.

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: 'Post a message to a Slack channel or DM under the bot's identity.' The verb 'post' and resource 'message' are specific, and the context of bot identity differentiates it from other Slack actions like update or delete.

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?

No guidance on when to use this tool versus alternative Slack messaging tools (e.g., slack_post_ephemeral, slack_me_message, slack_schedule_message). No prerequisites or exclusions mentioned.

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