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

With no annotations, the description carries the burden well: it discloses data provenance (5-minute snapshots), the 400-before-payment behavior for unlisted coins, and the x402 pricing ($0.004 USDC on Base or Solana). Missing only explicit read-only/no-side-effect confirmation, but the payment and error preconditions are genuinely useful behavioral context.

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?

Front-loaded trigger followed by compact Input/Output/Example/Price blocks; every section carries signal. Slightly dense with pricing and example packed into one paragraph, but no wasted sentences.

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?

No output schema exists, and the description fully enumerates the return shape: current 1h funding and APR, 24h/7d/30d averages, percentile and z-score, positive-hour share, downsampled series, and OI changes. An agent knows exactly what it gets and what it costs before calling.

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 both params are already documented with symbol examples and the 24-720 default range. The description largely restates those ('hours (24-720, default 168)') and adds one useful nuance—statistics always cover 7/30 days regardless of window—so baseline 3 is appropriate.

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?

Specific verb+resource with explicit scope: judging whether a perp's funding is unusually high/low and tracking open-interest build-up. The name and title align, and the funding/OI framing separates it from siblings like hl_funding_screener and hl_perp_metrics.

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?

Opens with a clear 'Use when...' trigger covering the two main analysis cases (funding extremes, OI build-up). It doesn't name alternative siblings or state when NOT to use it, so routing between hl_funding_history and hl_funding_screener 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.