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

With no annotations, the description carries the burden and does well: it discloses the real-time scan behavior, the 8-hour normalization convention (critical for interpreting spreads across venues), the returned fields, and the $0.01 USDC per-call cost. Missing are rate limits, latency, or behavior when an exchange is unreachable.

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?

Three sentences, front-loaded with what it does, then what it returns, then the usage cue and cost. No filler; every clause adds information an agent would act on.

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 does describe the return payload (annualized yield, profit estimates, risk notes, long/short direction) and the pricing model. It could say more about ranking order or spread-sign conventions, but an agent has enough to call it correctly.

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 coverage is 100%, so limit, symbols, and minSpreadBps are already fully documented with defaults and examples. The description adds nothing parameter-specific; the 8-hour normalization note is useful context but is not tied to a parameter. 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 ('Cross-exchange funding rate arbitrage detector'), enumerates the four venues scanned (OKX, Hyperliquid, dYdX, Kraken Futures) and the normalization method. That level of specificity clearly separates it from siblings like perp_market_overview, yield_rates, and lending_rates.

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?

'Use for delta-neutral carry trade discovery' gives an explicit use case and the tool's scope (perp funding spreads only). It does not name an alternative tool or state when NOT to use it, 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.