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

Since no annotations are provided, the description must carry the full burden. It states 'Real result, no wallet' which implies a live decode without side effects, and mentions it's a free version with limited scope. However, it does not disclose output format, error behavior, or any API key/auth requirements, so it only partially covers behavioral transparency.

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?

Four short sentences, each earning its place: 'FREE' states the cost, the core function is front-loaded, 'Real result, no wallet' adds behavioral context, and the upgrade path is clearly indicated. No fluff or repetition.

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 tool with a simple input schema (one required object, one optional string) and no output schema, the description explains the key return elements (type, summary, risk level) and the distinction from the full version. It is sufficient for an agent to understand the tool's purpose and invocation, though it stops short of describing the output structure in detail.

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% (both 'chain' and 'typed_data' have descriptions in the schema). The description itself adds no parameter-level detail beyond what the schema already states, so it meets the baseline for high schema coverage without providing extra value.

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's function: 'Type + plain-English summary + risk level for an EIP-712 typed_data.' It uses a specific resource (EIP-712 typed data) and distinguishes itself from the sibling tool decode_signature by being the free, summary-only version. The title also reinforces this.

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?

Explicit usage guidance is provided: it's FREE, produces a real result without a wallet, and the description directly recommends 'Upgrade to decode_signature' when full field-by-field decoding is needed. This tells the agent when to use this tool versus the alternative.

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