Comment on a post

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

Annotations already indicate non-read-only, non-idempotent, and non-destructive. The description adds relevant context: owner_id must be negative for communities and positive for users, and it returns the new comment_id. These details go beyond the annotations and help the agent understand expected behavior.

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 extremely concise: two sentences that cover the core action, the key parameter nuance, and the return value. Every sentence is essential, and the structure is front-loaded with the primary 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 tool's simplicity, the description covers all necessary aspects: action, required parameters, owner_id convention, and return value. With an output schema present, the description does not need to detail return structure. It is sufficiently complete for a comment creation 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?

The input schema provides descriptions for all 3 parameters (100% coverage). The tool description adds extra context for owner_id, explaining the sign convention (negative for community). This enhances understanding beyond the schema alone.

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 the action ('Add a comment to a post'), identifies the resource (a post), and differentiates from sibling tools like vk_wall_post (create a post) or vk_wall_delete. The mention of owner_id convention and return value provides additional clarity.

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 implicitly indicates when to use it (to add a comment) but does not explicitly state when not to use it or compare with alternatives. For example, it doesn't contrast with vk_wall_edit or vk_wall_post for creating comments on posts.

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