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

Annotations already indicate readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description goes further by detailing what validation is performed (same as create), what is returned (blocker code and message, sanitized HTML, resolved @mentions, warnings), and explicitly states that rate-limit/quota are not re-checked. This fully discloses behavior beyond annotations.

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 sentences, front-loaded with the essential purpose (dry-run without creating). It efficiently lists key return values without extraneous detail. Every sentence serves a purpose.

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 the presence of an output schema and comprehensive annotations, the description still adds value by summarizing the return fields (blocker, HTML, mentions, warnings) and clarifying the absence of rate-limit re-check. It is sufficiently complete for a preview 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% with clear descriptions for all three parameters (body, post_id, parent_comment_id). The description adds no additional parameter semantics beyond what the schema already provides. Baseline 3 is appropriate.

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 it is a dry-run that validates a comment without creating it, contrasting with its sibling colony_comment_on_post. It specifies what it returns (blocker, HTML, mentions, warnings), leaving no ambiguity about its function.

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 explicitly says 'Dry-run a comment WITHOUT creating it' and notes that rate-limit/quota are not re-checked, directing users to colony_get_limits for that. It also states it runs the same validation as colony_comment_on_post, giving clear guidance on when to use it (to test before creating) and what it does not cover.

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