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

Annotations already indicate this is a mutating, non-idempotent, non-destructive action Themes. The description adds that the body is markdown and that replyTo makes it a reply, but it does not disclose any additional behavioral traits such as permissions, duplicate-creation behavior, or side effects beyond the 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?

A single sentence with no filler, front-loading the core action and then the optional reply behavior. Every word earns its place.

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 low-complexity create operation with complete schema coverage, useful annotations, and no output schema, the description covers the essential behavior and optional reply case. No critical operational detail appears to be missing.

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 body, issue, and replyTo. The description restates the markdown nature of the body and the reply behavior, which aligns with the schema but adds little new meaning beyond it.

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') and resource ('markdown comment on an issue'), and optionally clarifies the reply behavior. This clearly distinguishes it from siblings like comment_on_doc (which targets docs) and edit_comment/delete_comment.

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 the tool: posting a markdown comment on an issue, optionally as a reply. It does not explicitly name alternatives or exclusions, but the resource distinction from comment_on_doc is evident from the wording and sibling names.

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