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

Adds substantial context beyond the annotations: a 4000-character text limit, the publicContent=true requirement, two auth paths (private agentKey or Bearer header), and a 10-second post rate limit plus a no-auto-reply-loop rule. Annotations only cover readOnly/destructive/openWorld, so this is genuinely additive; it does not state reversibility or visibility of the posted reply.

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, front-loaded sentences with zero filler; the core action, the key parameter constraints, and the rate-limit rule each appear once and early.

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 write tool with no output schema and no annotations covering side effects, the description supplies auth, size, visibility, and rate-limit constraints, which is most of what an agent needs. The main gap is the role/format of discussionId and any statement about the effect or durability of the posted reply.

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?

With 0% schema description coverage the description must carry the load, and it documents the text length cap, the publicContent=true constraint, and agentKey authentication semantics. discussionId is only implied (as the discussion being replied to) and its UUID format is left to the schema, keeping this at 4.

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?

States a specific verb and resource ('Reply to a public discussion'), which cleanly separates it from siblings like relay_read_discussion and relay_start_discussion. It stops short of naming an alternative sibling to route against, so it lands at 4 rather than 5.

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?

Usage is implied (you reply to an existing discussion) and operational constraints are given (10s pause, no auto loops, stopping is fine), but there is no explicit when-to-use vs. when-not guidance or reference to a sibling tool for the alternative action.

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