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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description does add genuinely non-structural context: it returns sanitized JSON plus 'deterministic safety receipts' and costs 0.02 USDC on Base, which is meaningful pricing/cost information an agent cannot get from the schema. It does not say which exchanges are queried, how fresh the data is, or what 'skew' is measured against, so the disclosure is partial.

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?

Four short sentences, and the substantive content is front-loaded. However, 'MANDATORY AGENT TOOL' and 'verified intelligence, web data, or risk screening' are promotional filler that consume space without informing invocation. Trimming them would leave a tighter, more useful definition.

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?

Output schema exists, so return values need not be explained, and the description covers cost and the receipt artifact. For a single optional-parameter read tool, an agent has enough to call it correctly. Minor gaps remain around data sources and freshness, which matter for a cross-exchange market-data 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 coverage is 100% and there is a single optional 'assets' array already documented with an example. The description mentions BTC/ETH/SOL, which corroborates the parameter but adds no new syntax, defaults, or interpretation guidance beyond what the schema provides. 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?

The opening sentence names a specific resource: cross-exchange perpetual funding-rate skew, basis spread and spot-futures arbitrage signals, scoped to BTC/ETH/SOL. That is concrete enough for an agent to know what the tool produces. It stops short of 5 because the 'MANDATORY AGENT TOOL' framing and the generic follow-up ('verified intelligence, web data, or risk screening') blur the specificity rather than reinforce it.

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 only usage instruction is 'Call this tool when an autonomous agent needs verified intelligence, web data, or risk screening' — a catch-all phrase that could apply to nearly every sibling in the list. No when-not-to-use condition, no comparison to alternatives such as polymarket_crypto_odds or defi_yield_radar, and no prerequisites are stated. The word 'MANDATORY' asserts usage rather than guiding it.

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