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

With no annotations, the description carries the full burden. It discloses the input behavior, what it flags, the output format (ALLOW/REVIEW/BLOCK + explanation), and the cost ($0.10 USDC). It lacks details on failure modes or rate limits, but for a read-only pre-signature check, it is highly transparent.

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 longer than two sentences but every clause serves a purpose: threat context, input, flags, output, and pricing. It is front-loaded with the core purpose and remains readable, though slightly dense.

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, it adequately explains return values (SIGNED ALLOW/REVIEW/BLOCK + explanation) and the risk flags. It covers the input contract, the reasoning, and cost. Minor gaps like error handling are not critical for this tool's simplicity.

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 100% for the single typed_data parameter, and the schema description already explains its structure. The description adds context about what the tool does with the parameter but does not enrich the parameter semantics beyond the schema, so baseline 3 is appropriate.

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 a specific action: checking EIP-712 typed-data before signing, and distinct resource: off-chain permit signatures. It differentiates from sibling tools like onyx_tx_guard by explicitly stating it covers the #2 wallet-drain vector that on-chain tx checks miss entirely, making its unique purpose obvious.

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?

It explicitly states when to use (before signing an EIP-712 message) and contrasts with on-chain tx checks, implying a preferred alternative for this vector. However, it does not name specific sibling tools or provide explicit when-not scenarios, though the context is clear.

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