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

The description adds explicit behavioral context beyond the annotations by stating it 'Never signs or broadcasts.' This tells the agent that the result is a prepared but unsigned, unsubmitted transaction, aligning with readOnlyHint but providing a stronger guarantee. The one-selected-listing limitation also helps set expectations.

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?

Two short sentences with zero filler. The core purpose is front-loaded, and the critical caveat ('Never signs or broadcasts') is included without bloating the description. Every sentence earns its place.

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?

The description is complete enough for a prepare-style tool: it names the transaction type, the scope, and the safety boundary. The output schema likely describes the prepared transaction, and annotations cover the read-only behavior, so no essential operational detail appears to be missing.

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%, so the parameter descriptions already document buyer, tokenId, orderHash, and recipient. The description does not add new parameter-level detail, but the 'one selected NFH listing' phrase gives helpful context for tokenId and orderHash. This matches the baseline for high schema coverage.

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 ('Prepare') and a precise resource ('the Seaport fulfillment transaction for one selected NFH listing'). It clearly defines what the tool accomplishes and distinguishes it from signing or broadcasting actions. 'NFH listing' and 'Seaport' anchor it to a particular purchase flow.

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 makes the operating context clear: this is for one selected NFH listing and targets Seaport. It gives just enough context to know when to use it, though it does not explicitly name alternatives like prepare_mainnet_buy or mention when not to use it.

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