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

With no annotations provided, the description carries the full burden. It discloses payment details ('PAID $0.01 (x402, USDC on Base)'), that it is a pure offline decode ('never signs/broadcasts'), and the payment flow ('Without payment returns the x402 challenge; pass x_payment'). This is rich behavioral disclosure beyond what annotations would have provided.

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 description is dense but every sentence earns its place: cost, function, risk flags, context, safety, payment behavior, free teaser. It is front-loaded with the paid alert and structurally efficient, with no fluff or redundancy.

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?

Given the tool's complexity and lack of output schema, the description explains the output (plain English with risk flags) and the payment behavior. It covers the main use case and safety properties, making it complete for an agent to select and invoke correctly. The mention of the free teaser also provides a fallback option.

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 baseline is 3. The description adds value beyond the schema by explaining the x_payment flow (forwarded as X-PAYMENT header, omitted to get challenge) and that chain is optional and derived from domain.chainId. It also elaborates on the typed_data types supported, enriching the parameter semantics.

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 tool decodes off-chain EIP-712 typed-data signatures (Permit/Permit2/Seaport/generic) into plain English with specific risk flags. It distinguishes itself from siblings by explicitly mentioning the free teaser decode_signature_free, and its scope differs from approvals/simulate/token_safety.

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 to use the tool: when you need to decode a signature and assess risk before signing. It names the free alternative and notes that signatures are a top wallet-drainer vector, implying safety-critical use. It does not explicitly state when not to use it or compare with all sibling tools, but the context is sufficient.

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