reply-to-channel-message

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

Annotations already indicate this is a write operation (readOnlyHint=false), and the description reinforces that by explicitly calling it a WRITE operation and noting the confirm=true requirement. It also adds actor context ('as the signed-in user') that goes beyond structured annotations. No contradictions found.

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 two short sentences with no filler. The key verb and resource are front-loaded, and the safety-relevant WRITE/confirm note is included without redundancy.

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 moderately complex write operation with 6 parameters and no output schema, the description plus annotations and 100% schema coverage give an agent enough to invoke it correctly. It could optionally mention what happens after a successful reply or contrast with send-channel-message, but these are minor omissions given the schema's strength.

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 description coverage is 100%, so the schema already documents all parameters. The description adds no new parameter-level meaning beyond restating the confirm requirement, which the confirm parameter schema already explains in detail. Baseline 3 is appropriate given the full schema coverage.

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 specific action (REPLY), the resource (existing channel message), and the actor (signed-in user). The word 'existing' and 'thread' distinguish this from send-channel-message and other send variants, so an agent can identify the correct tool.

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 clear context for when to use this tool: when replying to an existing channel message as the signed-in user. It does not explicitly name alternatives or state when not to use it, but the 'existing' qualifier and 'channel message' scope make the intended usage unambiguous enough.

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