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

Annotations give readOnlyHint/openWorldHint, and the description adds substantial context: no custody, user signs the unsigned transaction, ERC-20 approval included, 0.25% fee disclosed, free, and safety behavior (transaction withheld when price impact exceeds maxPriceImpactPct unless allowHighImpact). It does not address quote expiry or rate limits, keeping it below a 5.

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?

Purpose is front-loaded in the opening clause, and the sentence stays information-dense without filler. It is packed with parentheticals and could be split for readability, but no clause is wasted.

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 an 11-parameter, no-output-schema tool, the description usefully enumerates what comes back (expected/min output, price impact, gas, fees, warnings, unsigned tx, approval). Missing only edge-case behavior such as quote expiration or failure modes (no route, insufficient liquidity).

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 schema already documents all 11 parameters thoroughly. The description only reinforces a few of them (toChain mode switching, taker requirement for a transaction) without adding syntax or constraints the schema doesn't already contain; baseline 3 applies.

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 ('token swap', 'cross-chain bridge') plus the routing providers (KyberSwap, LI.FI, Relay) and the parameter that selects mode ('set toChain'). An agent can immediately tell this is a quote/transaction-builder, distinct from a token-listing sibling.

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?

Clear conditional guidance: set toChain for bridging, omit it for same-chain; omit taker for a price-only quote. It lacks any reference to the sibling list_swap_tokens (e.g., 'use list_swap_tokens to discover supported symbols'), so alternative selection is only partially covered.

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