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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior. The description adds genuinely new context beyond that: the tool is free, requires no x402 payment challenge, and has a direct HTTP equivalent. This payment/auth-free disclosure is exactly the kind of behavioral detail 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?

The core purpose is front-loaded in the first sentence and payment details follow. The em-dash clauses are slightly verbose, but each carries real information (reproducibility, free access, HTTP endpoint), so little is wasted.

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?

With no output schema and no parameters, the description carries the return-content burden and does so by enumerating the rulebook's contents. An agent knows what it receives and that no payment is needed. A minor gap is the absence of return format (JSON/text) detail, but overall it is complete for a static-read 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 tool takes zero parameters, so the parameter baseline of 4 applies. The description correctly characterizes this as a direct-read endpoint requiring no input, consistent with the empty 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 clearly identifies the resource: a published detection rulebook enumerating every pattern, category, severity, normalization views, verdict rule, and sanitization method. This distinguishes it from the injection_scan and injection_precheck siblings, which perform verdicts rather than document the rules. It stops short of an explicit verb phrase naming the action, but the content enumeration is specific enough.

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?

'Read these before paying' provides an implicit when-to-use cue, orienting the agent toward consulting this before invoking paid verdict tools. However, it never names the specific sibling alternatives or states when-not to call it, so guidance remains implied rather than explicit.

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