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

With no annotations, the description carries the full burden and does disclose the critical behavioral trait: this is a paid call at $0.02 via x402 in USDC on Base or Solana, so an agent knows payment/auth is required before invoking. It also bounds the data scope to 90 days. It does not cover failure modes for an invalid ticker, rate limits, or response size for a 90-day query at 30m granularity.

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?

Everything sits in one dense sentence whose parentheticals carry pricing, range, granularity, and returned metrics with no filler. Leading with the price instead of the purpose is a slight front-loading miss, but no sentence is wasted.

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 4-parameter tool with no annotations and no output schema, the definition covers payment, time range, granularity, and the conceptual payload well. It stops short of describing the response shape (series of points with timestamps?) or behavior on invalid ticker / out-of-range dates, which matters given there is no output schema to fall back on.

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 the baseline is 3, but the description adds real meaning: 'one trade.xyz stock perp' clarifies ticker scope is single-market and restricted to trade.xyz perps, and 'up to 90 days' imposes a hard constraint on from/to that the schema does not state. The interval enumeration merely duplicates the enum, so the gain is modest rather than decisive.

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: 'Historical gap time series for one trade.xyz stock perp,' and enumerates the exact metrics returned (perp vs stock gaps, basis, funding, OI, cross-venue marks). It implicitly separates itself from snapshot siblings like get_gaps by emphasizing 'historical... up to 90 days,' but 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 'historical... up to 90 days; interval 30m/1h/4h/1d' framing, which suggests this is the time-series counterpart to a point-in-time gap tool. There is no explicit when-to-use or when-not-to-use statement and no mention of the closely related get_gaps or get_gap_sample siblings.

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