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

Beyond the readOnly/openWorld/non-destructive annotations, it discloses cadence (every 15 minutes), the derivation method (median of Binance/Bybit/Gate USDT indices), a data-quality caveat (unit is unverified), and the meaning of 'live' (near-real-time overlay, null when unavailable) with freshness defined as collection time. This is exactly the kind of behavioral context annotations cannot carry.

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-loads the core definition before usage, and every clause carries information. It is dense and somewhat overloaded in a single paragraph, but there is little genuine waste.

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?

With an output schema covering return values and annotations covering the safety profile, the description supplies everything else an agent needs: the dual-mode contract, data provenance, freshness semantics, and the unverified-unit caveat. Complete for a read-only, dual-mode 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 description coverage is 100% and already labels limit/offset/assetClass as 'List only' and window/maxPoints as 'Detail only', so the baseline is 3. The description reinforces the ticker switch and the maxPoints sampling nuance but adds little parameter meaning beyond what the schema states.

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 resource (TradFi reference prices for equities, ETFs, metals, commodities, FX) and precisely defines what a 'reference' is: the median of 2-3 derivatives-venue index prices in USDT, not an exchange last trade. This semantics is unique among siblings like spot_quote/futures_quote, so an agent can tell it apart without opening either schema.

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?

Clearly splits the two modes: omit ticker to page the catalog, pass ticker for one instrument with constituents/history sampled to maxPoints, and notes no API key is required. It stops short of naming alternatives or exclusions (e.g. when to prefer a crypto quote tool), so it is clear context without explicit routing.

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