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

Beyond the existing annotations (readOnlyHint, idempotentHint, destructiveHint), the description adds valuable behavioral context: the output contains no transaction and no calldata, the quote is non-executable, it is free with no technology service fee, and it is a read with no transaction notional. These details materially shape agent expectations.

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 description is tightly structured: purpose is front-loaded, the critical sell_amount unit clarification is one sentence, and the non-executability/fee behavior is concise. No sentence is redundant or filler.

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?

Given the output schema exists and annotations are strong, the description covers the core behavioral caveats an agent needs: non-executable, no calldata, sell_amount units, and fee status. It falls slightly short of full completeness because taker and caller_id semantics are undocumented, but these are optional and the overall context is sufficient for correct high-level use.

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?

The schema has 0% description coverage, so the description carries the burden of explaining parameters. It only clarifies that sell_amount is in the sell token's base units. Other parameters such as taker, caller_id, chain, sell_token, and buy_token receive no semantic explanation, leaving meaningful gaps for correct invocation.

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?

The description opens with 'INDICATIVE swap quote on an EVM chain' and immediately provides scope ('pricing and routing only'). It clearly distinguishes itself from executable swap tools by stating the quote is not executable and returns no calldata, which differentiates it from siblings like evm_swap.

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?

The description clearly frames when this tool is appropriate: for indicative pricing/routing only, not for execution. It explicitly says the quote 'cannot be signed' and 'returns no transaction', which implies evm_swap should be used when an executable quote is needed, though it does not name the sibling tool explicitly.

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