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

With no annotations, the description carries the full behavioral burden. It does well by disclosing that the tool only prepares an unsigned payload — it does not execute the transaction — and that a seller wallet signature is required afterward. This is a key safety-relevant behavior. It could go further by stating whether any on-chain state is touched or how the payload is returned, but the core non-execution and signature requirement are 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?

Two sentences, front-loaded with the action and object, and the critical signature requirement is stated immediately. No filler or redundant phrasing — every phrase contributes meaning.

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 no annotations and no output schema, the description covers the essential operational context: it prepares, not executes, and requires seller signature. It doesn't explain the return format or what the caller should do with the unsigned payload (e.g., sign it externally), which could leave a small gap for an agent, but the core flow is understandable. The moderate complexity and well-documented parameters keep the gap minor.

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?

The input schema already documents all three parameters at 100% coverage, so the description is not required to restate them. The description adds only loose context ('buyer offer', 'seller wallet') that maps onto the schema fields but provides no additional semantic detail about formats or constraints. Baseline 3 is appropriate for full 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?

The description names a specific verb ('Prepare') and a precise resource ('unsigned atomic swap transaction payload accepting a buyer offer'), which clearly distinguishes this from sibling marketplace tools like marketplace_browse_listings or marketplace_cancel_offer. The '.i domain' scope and 'buyer offer' framing make the intent unambiguous.

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 clearly implies the seller-side use case: accepting a buyer offer. However, it does not explicitly state when not to use this tool or name alternatives for related actions (e.g., marketplace_make_offer for buyers, marketplace_cancel_offer for withdrawing offers). Context is clear, but no exclusions or alternative routing are provided.

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