swap_build

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

With no annotations, the description carries the full burden and does so richly: returns base64 signed by the caller, server never holds keys or signs, transaction is simulated against the wallet first, and a 0.1% XNT platform fee (>0.01 XNT) surfaces as platformFee. These are exactly the behavioral traits the agent needs beyond structured fields.

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?

Core action and routing are front-loaded, followed by signing model and fees. Dense but each sentence (fee, simulation, signing) earns its place; only minor redundancy with the schema on the native/mint wording.

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 complex swap-builder with no annotations and no output schema, the description covers the return format, signing responsibility, fee behavior, and a pre-signing warning. Only marginal gaps (e.g., no explicit failure/error behavior) remain.

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 parameters are already documented; the description mostly repeats the schema (native for XNT, mint addresses) rather than extending it. The APEX mint address is a small value-add, but baseline 3 is warranted.

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 (Build) and resource (UNSIGNED swap transaction on X1) and adds routing scope: best price across XDEX and APEX AMM, direct or two hops. No sibling tool builds swaps, so the agent can immediately distinguish it.

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?

Gives clear usage context: build-then-self-sign flow, use mint addresses or "native", and 'Check priceImpact before signing — thin pools move hard.' Lacks an explicit when-not or named alternative, but the workflow guidance is strong.

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