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

With no annotations, the description carries the full burden and does well: it discloses non-execution of the code, determinism, the 45-rule engine, the verdict taxonomy, the HTTP method, and the paid-per-call USDC/x402 model on Base or Solana. Gaps remain around how the payment handshake actually works (prepay vs 402 challenge), rate limits, and idempotency for a paid endpoint.

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?

Purpose is front-loaded in the first clause, then engine traits, then pricing/transport, then parameters — a logical ordering with no filler. The inline Input block is mildly redundant but is justified as the only parameter documentation available given the empty schema.

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?

For a paid 2-parameter scanner with no annotations and no output schema, the description supplies the verdict vocabulary, the language set, the payment rail, and the HTTP method — enough to call it correctly. What is missing is the shape of the findings array and the payment negotiation mechanics, which an agent handling a paid endpoint would want.

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 coverage is 0%, so the description must compensate, and it does: both parameters are documented and the allowed language values (python|javascript|typescript|tsx) are supplied even though the schema declares no enum. It stops short of saying whether 'language' is optional, defaulted, or auto-detected — relevant since required parameter count is zero.

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 (scans), a specific resource (Python/JS/TS source), and the exact return contract (findings, severity, PASS/WARN/BLOCK verdict). The qualifiers 'deterministic', 'no LLM', and '45 rules' distinguish it cleanly from the LLM-based siblings such as x402-ai-code-review and x402-ai-diff-review.

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?

'Pre-execution code security gate' plus 'without executing it' establishes the usage context clearly, and 'no LLM' implies the deterministic-vs-AI choice. However, it never names a specific alternative tool or states when NOT to use it (e.g. for contract audits use x402-smart-contract-audit), so the routing is inferred rather than explicit.

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