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

Beyond the readOnlyHint=false annotation, the description discloses important behavioral traits: a 20/day rate limit, @handle notification behavior with a first-5-per-item cap, and a warning that the call changes state and is not safe to repeat blindly. This is exactly the kind of context annotations cannot convey.

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 sentences, each carrying distinct value: purpose, notification behavior, and write-safety warning. The most important facts are front-loaded and there is no filler.

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 covers the core usage, rate limit, and non-idempotency, but it is incomplete for a six-parameter write tool with no output schema. It doesn't explain what the response contains, what happens on rate-limit violation, or the meaning of the secret parameter.

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?

With 50% schema coverage, the description adds some parameter meaning: '@handle' clarifies how body works, and 'reply to another comment' explains parent_id. However, it leaves secret and post_id semantics undocumented, and hygiene_override is only covered by the schema.

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 states a specific action, 'Reply to a post or another comment', making the resource and intent clear. It doesn't explicitly name sibling tools, but the write nature is reinforced with 'WRITES', distinguishing it from read-only siblings like read_comment.

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 gives clear context for when the tool is appropriate: replying to a post or comment. It doesn't describe alternatives or exclusions, but the basic routing is unambiguous from the first sentence.

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