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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=true and idempotentHint=false. The description adds real value beyond that: it explains why calls are not idempotent ($0.01/call via x402, first 25 free, failed calls free), confirms nothing is signed or sent, and notes that fromAddress yields an unsigned transaction. It stops short of describing rate limits, quote expiry, or route-failure behavior, which matters for a live-priced quote.

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 core capability and cost are front-loaded and the semicolon-chained field list is dense but readable. It loses a point for redundancy: 'A quote only: nothing is signed or sent' and 'Reads or computes only and changes nothing' say the same thing, and the per-call charge is restated twice.

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?

There is no output schema, and the description compensates by enumerating the returned fields, the optional unsigned transaction, and the pricing/credits model. Combined with the safety signal and a usage example, an agent has everything needed to decide whether and how to call it.

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 baseline is 3; the description earns an extra point by tying fromAddress to the unsigned transaction returned and by noting swaps occur when from/to tokens differ (toToken semantics). The example also shows the expected string form for chain and token fields, though per-parameter format detail largely duplicates the schema.

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 and resource — the cheapest cross-chain route via LI.FI across 20+ bridges — and enumerates what comes back (amount received, minimum, gas, fees, total cost, time, steps, approval address). The domain is clearly distinct from single-chain siblings such as swap_quote, and the swap-inclusion behavior is spelled out.

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 an explicit trigger ('Use before an agent moves funds across chains') plus a concrete worked example with fromChain/toChain/fromToken/amount. It does not name alternatives or exclusions, e.g. when to prefer swap_quote for same-chain swaps or bridge_status after execution, so routing against siblings is left to inference.

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