Reply in Channel Thread

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

Annotations are minimal (no readOnly, destructive, etc.), so description carries burden. It discloses that the reply is posted as the connected member, is org-visible, and returns the posted reply. This adds transparency about visibility and return value.

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 that cover purpose, return, visibility, and parameter guidance. No wasted words. Front-loaded with the key action.

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?

Covers all essential aspects: required parameters, resolution steps, return value, visibility. With 3 params and no output schema, it is sufficiently complete. Does not mention error handling, but that is acceptable for a simple 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%, so baseline is 3. The description adds value by specifying how to obtain channel_id and parent_id (via list_channels and read_channel), which is critical context beyond the schema descriptions.

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 (reply in a thread), the resource (specific message in a channel), and the context (as connected member). It distinguishes from siblings like post_to_channel and reply_to_conversation by specifying threading and channel membership.

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?

Explicitly tells the agent to resolve channel_id via list_channels and parent_id via read_channel, providing clear prerequisites. Does not explicitly exclude alternatives, but the context makes it clear when to use (replying to a thread) vs posting new messages or replying to DMs.

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