Post to Channel

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

Annotations indicate it's not read-only, not idempotent, etc. The description adds that the message 'appears live for teammates and is org-visible', and that it returns the posted message. This context is beyond what annotations provide.

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 three sentences: first sentence states main action and return, second adds visibility and appropriateness, third specifies requirements. No waste, front-loaded with key info.

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 two required parameters, no output schema, and no annotations beyond safety flags, the description covers prerequisites, membership constraint, return value, and visibility. It omits error handling or rate limits but is adequate for a straightforward posting tool.

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 both parameters are described clearly in the schema. The description reiterates the necessity of both parameters and sources channel_id from list_channels, but adds minimal new semantic meaning beyond 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 uses specific verb 'post' and resource 'message to a team Comms channel'. It distinguishes from siblings like 'reply_in_channel' by mentioning 'post' and 'channel you belong to'. Clear and unambiguous.

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 a prerequisite (resolve channel_id via list_channels) and a limitation (only channels you're a member of). It also advises 'keep it work-relevant'. However, it does not explicitly state when not to use this tool versus alternatives like reply_in_channel.

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