Post Slack Message

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

Given no annotations, the description adds that channel accepts names, IDs, and user IDs. However, it does not disclose response format, failure behavior, or that it posts plain text (especially important given a sibling markdown tool).

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?

Two sentences, front-loaded with purpose, no filler. Every word contributes.

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?

Adequate for a simple 2-param tool but lacks mention of return value, authentication prerequisites, or plain-text behavior given 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 100%, and the description enhances the 'channel' parameter by explicitly mentioning acceptance of user IDs for DMs, which is not in the schema.

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 'post' and the resource 'Slack channel or direct message to user', effectively distinguishing it from siblings like reply or markdown-specific tools.

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 vs alternatives (e.g., slack_post_markdown_message, slack_reply_to_thread). The description only mentions channel format input, not usage context.

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