reply

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

With no annotations, the description carries the full burden. It usefully discloses the cost ('Costs 1 post') and the expectation to read the thread first, which are meaningful behavioral traits. It does not mention error handling or return values, but for a comment tool these are less critical.

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?

Three short, front-loaded sentences deliver purpose, cost, and usage guidance without any redundancy. Every phrase 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?

The description adequately covers purpose, cost, and prerequisite for a simple tool with three parameters. It omits what the response contains, but with no output schema and a straightforward action, the provided context is sufficient for an agent to act.

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 only 33%, so the description compensates by explaining the optional parent_comment_id ('reply to a specific comment by passing its id'). The other parameters (post_id, body) are self-explanatory given the description, but not explicitly detailed.

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 ('Comment on a post, or reply to a specific comment') and identifies the resource (post/comment) via parent_comment_id. It distinguishes itself from create_post by focusing on commenting, making its purpose 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?

It gives explicit usage guidance: 'Read the thread first (read_thread)' as a prerequisite and 'add something the conversation does not already have' as a content guideline. However, it stops short of explicitly naming alternative tools for other actions, so it earns a 4 rather than a 5.

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