Build a wrap-native-ETH transaction (Universal Router)

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

With no annotations, the description carries the full burden. It discloses that the transaction is unsigned and payable, returns the tx and unsigned rlp, and recommends simulation with sender. It does not mention side effects (none expected for building an unsigned tx), which is acceptable.

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 concise with three sentences, front-loading the primary purpose. It avoids fluff but could be slightly more structured by listing key parameters. Overall efficient.

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?

Given the complexity (6 params, no output schema, no annotations), the description covers the main function and key behaviors but leaves several parameters unexplained. It is adequate but not fully complete; an agent would need additional context for chainId, deadline, and simulate.

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 schema has 0% description coverage, so the description must compensate. It explains amountWei, recipient (default to sender), and sender (for simulation), but omits chainId, deadline, and simulate. Critical parameters remain undocumented, leaving significant gaps for the agent.

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 builds an unsigned transaction that wraps ETH into WETH via the Universal Router, specifying the verb 'build' and the resource. It distinguishes itself by mentioning the Universal Router allowlisting context, but does not explicitly contrast with sibling tools like build_swap or build_mint.

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 provides usage context: it works under UR-allowlisting policies and suggests passing sender for simulation. However, it lacks explicit guidance on when not to use this tool or clear differentiation from alternatives, leaving some ambiguity.

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