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

Beyond the annotations (readOnlyHint, idempotentHint, destructiveHint), the description discloses meaningful behavior: it returns expected output, a safe minOut with a dynamic slippage buffer (2.5% normal / 4% during Crash Shield), and a fee breakdown. This adds real context about what the call yields and its side-effect-free nature, with no contradictions.

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?

Two dense sentences front-load the core purpose and then pack in return values, slippage policy, and fees without wasted words. The 'Read-only' tag is redundant with annotations but harmless and brief.

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 tool has only two parameters, an output schema, and strong safety annotations, the description supplies all necessary behavioral context: non-execution, direction semantics, slippage policy, and fee reporting. Nothing an agent needs to choose or invoke it correctly is missing.

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 description adds meaning to the direction enum by defining buy as ETH→GBLIN and sell as GBLIN→ETH, which complements the schema's amount_in note. With 50% schema description coverage, this mapping meaningfully reduces ambiguity, although the description does not explicitly re-explain every parameter.

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 a precise verb and scope: 'Preview a buy (ETH→GBLIN) or sell (GBLIN→ETH) without executing.' It clearly differentiates itself from execution-oriented siblings by stating it does not execute and is read-only, and the title reinforces the quote/mint/redemption purpose.

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?

It provides clear context: use this tool when you need a non-executing preview of a mint or redemption quote. It does not explicitly name alternative tools or say when not to use it, but 'without executing' and 'Read-only' are strong usage signals that prevent confusion with execution tools.

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