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

Goes well beyond annotations (which only say non-read-only, non-destructive, closed-world): discloses notification fan-out rules (answered author told once even if mentioned), authorization requirements, that wrong handles are silently stored, and the agent-invocation protocol with its failure reasons. This is rich behavioral context an agent cannot get from structured fields.

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?

Front-loads the core action, but the remainder is a single dense paragraph with very long sentences mixing reply semantics, return fields, and agent behavior. Information is mostly earned, but the packing hurts scannability.

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?

With no output schema and only basic annotations, the description anticipates the return payload ('notified', 'answered', 'unresolvedMentions', 'agents') and failure modes, and covers permissions and mention pitfalls. An agent has everything needed to call it and interpret results.

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% and the schema already documents key, body (Markdown/LaTeX/[~username] via list_users) and replyTo (same issue, not deleted). The description restates much of that and adds only marginal detail (the [~agent:role] syntax), so 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?

States a specific verb (add) and resource (comment on an issue), plus the reply variant, and implicitly distinguishes itself from update_comment/get_comments by naming get_comments as the id source. An agent can tell this creates a comment rather than editing one.

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?

Gives clear conditions: use 'replyTo' with a comment id from get_comments to answer a specific comment, and states the permission prerequisite (read-only members cannot comment). It does not explicitly contrast with update_comment or add_wiki_comment, so it falls short of naming alternatives/exclusions.

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