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

Goes well beyond the readOnlyHint/openWorldHint annotations: it discloses that no transaction is signed or executed, that a fixed placeholder sender is substituted when none is supplied, and the exact cost model ($0.002 USDC per successful call via x402 on Base/Solana/Arc, failures free). These are non-obvious operational facts an agent must know before calling.

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?

Four tight clauses, front-loaded with purpose then return values, then the quote-only constraint, then the sender caveat and price. Every sentence carries information an agent needs; nothing is repeated from the schema.

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?

With an output schema present, the description need not explain return values, yet it summarizes them anyway, and it covers the payment and no-execution caveats. The only gap is routing guidance against the many other DEX-quote siblings, which leaves a small selection ambiguity.

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 description coverage is 100%, so tokenIn/tokenOut/amountIn/chainId are already fully documented. The description only adds context for the optional sender parameter (placeholder fallback, quote unaffected) and does not explain units or the wrapped-token convention, so 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 — 'SushiSwap route quote for an exact-input swap on one EVM chain' — and enumerates what the quote contains (amount out, price, price impact, gas, route tokens). Naming SushiSwap plus 'exact-input' implicitly separates it from the 1inch pathfinder and Jupiter routing siblings, but it never explicitly contrasts with them.

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?

'Quote only, no transaction data' tells the agent this is not an execution tool, which is useful scoping. However, there is no explicit statement of when to prefer this over crypto_1inch_pathfinder_quotes or other routing siblings, and no stated prerequisites beyond the sender note.

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