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

With no annotations, the description carries full burden. It usefully discloses what the response contains (current rate, window mean, annualised mean, extremes, positive-period count, paying side), which is real value. But it says nothing about default window, payment/x402 cost, rate limits, or error behavior for an undocumented-parameter tool.

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?

A single front-loaded sentence that enumerates the payload efficiently. The only waste is the leading 'x402-polyperp-funding:' prefix, which merely repeats the tool name.

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?

Five parameters with no schema documentation, no annotations, and no output schema — the description compensates on the return side by listing the summary fields, but the input side (which identifier, what window/limit defaults) is wholly uncovered for a tool the agent must call correctly on the first try.

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% across five string-typed parameters, and the description adds almost nothing: 'one ... market' hints at single-market scoping and 'over the window' vaguely touches `hours`, but the id/symbol/instrument redundancy and `limit` are left entirely unexplained. The agent cannot tell which identifier to supply or what the defaults are.

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+resource+scope: hourly funding-rate history for one Polymarket Perps market, and enumerates the returned metrics. The 'Polymarket Perps' qualifier implicitly separates it from x402-hyperliquid-funding and x402-funding-rate, though it never names those siblings explicitly.

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 through the phrase 'the summary a carry position needs', which signals the carry/funding-arb scenario but gives no explicit when-to-use, when-not, or alternative tool (e.g. hyperliquid-funding for non-Polymarket perps). The agent must infer routing.

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