US spot Bitcoin and Ethereum ETF daily flows

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

Annotations declare readOnlyHint and openWorldHint. The description adds that results are one row per finalized US trading day, denominated in USD, and covers about 14 months of history, providing a clear picture of data granularity and temporal range.

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?

Two sentences, front-loaded with usage instruction, followed by a compact description of output fields and data history. No redundant phrases.

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?

The description fully explains the output structure (row per day/asset, fields), which compensates for the lack of an output schema. It also covers history length and data currency, making it sufficient for the tool's simple interface.

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?

The schema already provides 100% parameter descriptions (days and asset). The description does not add additional parameter-level detail, so it meets the baseline but does not exceed it.

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 opens with a direct instruction ('Call this when the user asks about Bitcoin or Ethereum ETF flows') and enumerates specific metrics (daily net inflows/outflows, cumulative flow, total net assets) and example ETFs (IBIT, FBTC, ETHA). This clearly distinguishes it from sibling tools focused on different market data.

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?

The description explicitly states when to invoke ('when the user asks about Bitcoin or Ethereum ETF flows') and outlines the range of queries it satisfies. It does not mention alternatives, but no sibling tool covers ETF flows, making the use case unambiguous within the toolset.

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