Post a comment on a forum thread

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

The description adds value beyond the annotations by disclosing that login is required and that the comment is posted from the authenticated user's account. It also reveals the dual create/update behavior, which is not explicitly stated in the annotations. This provides useful behavioral context without contradicting the annotations (readOnlyHint=false, idempotentHint=false, destructiveHint=false).

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 a single, concise sentence that front-loads the action and resource, then clarifies the create/update variation. It contains no fluff, repeats no schema details, and is immediately scannable, making it an exemplary concise description.

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 tool's moderate complexity (4 parameters, 2 required, all with rich schema descriptions) and the presence of an output schema, the description covers the essential prerequisites (login, authenticated user) and the core create/update capability. It does not mention the reply functionality via `parentCommentId`, but that is thoroughly documented in the schema, so the description is sufficiently complete for correct selection and invocation.

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?

The schema already provides 100% description coverage across all four parameters, including detailed explanations for `id`, `parentCommentId`, `threadId`, and `comment`. The description's reference to 'or update an existing one by passing its `id`' reinforces the purpose of the `id` parameter but adds negligible new meaning beyond the schema. Thus, the description meets the baseline without significantly enhancing parameter understanding.

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 the specific verb 'Post' to identify the action and 'comment on an AniList forum thread' as the resource, clarifying that it creates a new comment or updates an existing one by passing its id. This distinguishes it from siblings like post_thread (creates threads) and delete_thread_comment (deletes comments), making the purpose specific and unambiguous.

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 states the prerequisite '[Requires login]' and notes the action is performed from the authenticated user's account, giving some usage context. However, it does not explicitly mention when to use this tool versus alternatives such as post_thread or get_thread_comments, nor does it provide exclusions. The usage is implied by the purpose but not fully articulated.

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