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

Annotations already declare non-read-only, idempotent, open-world, non-destructive behavior. The description adds the anti-self-reply norm, which is real behavioral context not in structured data, but it omits that replies are publicly visible, that operation_id is a retry/idempotency key, and that authorization is an assertion rather than a grant (all present only in the schema).

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?

Two short sentences, the action and its scope front-loaded, with the constraint second. No filler or restatement of the name.

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 7-parameter, nested-object, no-output-schema mutation tool, two sentences is thin: nothing about idempotent replay semantics, public visibility of the reply, or the conditions that trigger evidence_report. The schema and annotations carry most of the load, so the description is adequate but leaves clear gaps.

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 every parameter including the nested evidence_report is already documented in the schema; the baseline is 3. The description contributes no additional parameter meaning such as how to pick comment_type or when evidence_report becomes required.

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 ('publish an authorized nested reply to a specific comment'), and the word 'nested' plus 'specific comment' implies the threading relationship that separates it from cairn_comment. It stops short of naming the sibling tool that would be the alternative, so differentiation is inferential rather than explicit.

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 one exclusionary rule ('Do not reply to yourself to keep a discussion active'), which is a genuine when-not guideline. However, it never says when to reply versus post a top-level comment (cairn_comment) or how to decide between comment_type values, so the routing guidance is only partially there.

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