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

Annotations only declare readOnlyHint=false and destructiveHint=false, which alone would leave an agent unsure whether the call mutates state. The description fills that gap by disclosing the return shape (flagged/not_flagged plus a score per category), the quota cost, and the API key requirement. It stops short of covering failure modes such as invalid keys or messages over the length limit.

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?

Four short sentences, front-loaded with what the tool does, then return shape, then cost, then auth. Each sentence carries distinct information; the only minor density cost is cramming the key-creation pointer into the final sentence.

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?

No output schema exists, and the description compensates by naming the return fields and the per-category score. Auth and quota are covered as well, so an agent has what it needs to call this correctly; only error behavior is unaddressed.

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 is already documented, and the description only adds that evaluation uses the project's categories and thresholds. It adds no meaning for user_id or context_id beyond the schema text, which is the expected baseline-3 outcome when the schema does the work.

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: checks one chat message with Paxmod using the project's categories and thresholds. The scope ('one chat message') separates it from policy-level siblings in spirit, but it never names test_policy or test_policy_on_project explicitly, so differentiation still requires inference.

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 a useful prerequisite ('Needs a Paxmod API key (create_test_api_key gives one)') and a quota caveat ('Counts as one of the project's messages, like a live request'). It does not say when to prefer this over test_policy or test_policy_on_project, so the choice among moderation-testing siblings is left implicit.

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