Post to Channel

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

Annotations only indicate non-read-only, non-idempotent, and non-destructive. The description adds meaningful behavioral context by disclosing visibility ('appears live for teammates and is org-visible'), identity ('as the connected member'), and permission constraints ('only post to channels you're a member of'). This goes beyond the annotation booleans.

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?

Three compact sentences with the core action first, followed by visibility caveat and usage prerequisite. Every sentence contributes necessary information with no redundancy or filler.

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?

For a simple two-parameter tool with full schema coverage and no output schema, the description covers the action, audience, prerequisite, and constraints. It omits error handling or rate-limit specifics, but those are not critical for a basic post operation. The description is sufficiently complete for an agent to use this tool effectively.

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 already describes both parameters (100% coverage), so baseline is 3. The description adds valuable workflow guidance: channel_id must be resolved via list_channels and is limited by membership. This clarifies how to obtain and validate the parameter, which is 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 a specific verb ('Post'), a clear resource ('a team Comms channel'), and a scope ('you belong to, as the connected member'). It also states the return value ('return the posted message'), making it distinct from siblings like read_channel and reply_in_channel.

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 clear prerequisite ('Resolve channel_id via list_channels') and a membership constraint ('you can only post to channels you're a member of'). It implies when to use this tool (new post vs. reading or replying), but does not explicitly name alternatives or state when not to use it.

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