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

Annotations already cover read-only/open-world, but the description adds real behavioral context beyond them: expected latency ('Seconds'), explicit scope limits (no historical OI, no liquidations, no orders), and crucially the payment/auth model (0.55 USDC on Base via x402, payTo wallet). Some of that surface is token/identity marketing rather than invocation-relevant, which keeps it below a 5.

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 two sentences are well front-loaded with purpose and input. The remainder drifts into fee/token-address, agent-identity verification, and payout-wallet details, which bloat a single dense paragraph; only the x402 pricing line clearly earns its place.

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 one-optional-parameter tool with no output schema, the description does the necessary work by enumerating the returned fields (prices, funding, OI, volume, watchlist candidates, sources, timestamp, limits). Missing only how large the 'limits' are or how the watchlist is chosen.

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 the single enum parameter is fully documented in the schema, so baseline is 3. The description repeats the enum values and adds a concrete example ({'focus':'major'}), but it never explains what 'funding-arb' actually changes in the output, so it adds only marginal meaning.

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 names a specific verb and resource ('a quick read of Hyperliquid's perp market') and enumerates exactly what is returned: mark prices, funding, open interest, 24h volume, plus up to three funding-watchlist candidates. It is clearly distinguishable from narrow siblings such as hl_funding_snapshot or hl_top_movers by its breadth, though it never names an alternative 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?

It says 'A quick read' and 'Seconds', implying a fast snapshot use case, and it does give exclusions ('no historical OI or liquidations, no orders'). But it never tells the agent when to prefer it over funding_arb_scan, hl_funding_snapshot, or daily_bundle, leaving sibling routing to inference.

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