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

Annotations already declare readOnly/openWorld/idempotent, and the description adds substantial context beyond them: the 422 behavior when no pool has liquidity (not charged), the 5xx behavior on malformed node answers (not charged), 0.3-2s latency, USD 0.003 price, and a shared 10-read/day free pool. It also flags returned on-chain data as untrusted, which is valuable safety context.

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?

Dense and front-loaded: the quote operation and inputs lead, followed by return shape, caveats, errors, and pricing. It is long, but nearly every sentence carries distinct operational value for an agent; only minor compression is possible.

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 no output schema, the description compensates by enumerating the return fields (amount_out/amount_out_raw, fee_tier, gas_estimate, price, all fee tiers tried, disclaimer). Combined with error and pricing behavior, an agent has everything needed to call and interpret this tool.

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 the schema already documents chain enum, token patterns, and the 'exactly one of amount_in or amount_in_raw' constraint. The description restates the amount formats (decimal units vs. raw base units) but adds no syntax or semantics beyond the schema, so baseline 3 is correct.

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 precise verb+resource+scope: an exact-input swap quote on Uniswap V3 (QuoterV2, read-only eth_call) on Ethereum or Base. This is easily distinguishable from siblings like get_token_price or get_fx_rates, which return reference prices rather than single-pool spot quotes.

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?

Explicitly frames when use is appropriate and when it is not: 'A spot quote, not a firm price', 'one Uniswap V3 pool at the latest block, exact input, no gas or other venues', and 'never use it as an oracle'. It doesn't name a sibling alternative for oracle-style pricing, so it stops short of a 5.

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