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

No annotations are provided, so the description carries the full burden. It usefully discloses the return shape (hex, mnemonic, description, or the full table) and the monetization model (5 free trial calls per signed wallet), but says nothing about error behavior when a lookup misses or what happens if both parameters are omitted.

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?

A single tight sentence with the lookup behavior and return payload front-loaded. The 'EVM Opcodes:' prefix and the emoji CTA are mild overhead but do not obscure the core content.

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, no annotations, and 0% parameter coverage, the description must do heavy lifting. It covers the return payload and pricing, but leaves the critical parameter mapping and the optional/required status of both inputs unexplained, so the definition is only partially complete for this 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?

Schema description coverage is 0% for both parameters, and the description does not map the two input modes ('hex code' vs 'name') to the actual parameter names 'query' and 'opcode'. An agent cannot tell from either source which parameter expects a hex string and which expects a mnemonic.

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 states a specific verb and resource — looks up an EVM opcode by hex code or name — and names the return payload (hex, mnemonic, description, or the full table). That is enough for an agent to distinguish it from the many unrelated x402 siblings, though it makes no explicit contrast with any closely related tool.

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 implies the tool accepts either a hex code or a name, but never states when to use it or which of the two parameters to supply for each lookup mode. There are no exclusions, prerequisites, or alternatives named, so an agent must infer the invocation path.

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