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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), yet the description still adds substantive behavior: per-call cost of $0.09 USDC or credits, that payment headers (X-Payment / X-Payment-Tx / Bearer fg_…) must go in MCP headers and not in params, and which candidates get excluded and why. Missing is any note on latency, caching, or failure/refund behavior for a paid call.

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 first clause is well front-loaded, but the body is duplicated wholesale between Chinese and English, the four argument names are listed twice, and the detailed exclusion/fee explanation exists only in Chinese. A large share of the tokens repeat rather than add information.

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 a paid, open-world tool with no output schema, the description does a fair job sketching the return shape (ranked routes, pool address/price/liquidity, exclusion reasons) and payment mechanics. However, with 0% schema coverage on four parameters and no sibling differentiation against spread_scan, an agent still cannot confidently build a correct call from this alone.

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 0% and all four parameters carry only bare titles, so the description must compensate and does not. It merely restates that symbol is required and the rest optional, and relists the names; the meaningful ambiguity between symbol, token and quote (base asset vs contract address vs pricing pair) and the units/format of min_liquidity are never explained.

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 states a concrete deliverable: all routes ranked by net spread, per-chain best DEX pool detail (pool address, price, liquidity), rejected candidates with rejection reasons, and fee-split assumptions. The word "full" implicitly contrasts with a lighter scan, but the sibling arb-spread.spread_scan is never named, so the agent must infer the distinction.

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?

Usage is only implied by the word "full" and by the framing question; there is no explicit "use this when you need route-level detail, use spread_scan for a quick yes/no". The payment precondition is clearly stated, which is real guidance, but routing versus alternatives is left to inference.

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