CME futures positioning (weekly COT report, BTC + ETH)

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

Beyond the readOnly and openWorld annotations, the description adds valuable context: data comes from 'official CFTC data updated every Friday,' and it warns that 'a large share of hedge fund shorts is the market-neutral basis trade, so the weekly change carries more signal than the level.' This is non-obvious behavioral information that helps interpretation.

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 description is two sentences: one for usage and output, one for an interpretive caveat. Every sentence adds value, and the most important information (when to call) is front-loaded.

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 tool with no parameters and no output schema, the description correctly covers the data source, update frequency, the key data points returned, and a critical interpretation nuance. It is sufficiently complete for an agent to decide when to call and what to expect.

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 tool has zero parameters (schema is empty), so the parameter description baseline is 4. The description does not need to explain parameters; it focuses on the output instead, which 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?

The description states a clear action: 'Call this when the user asks how hedge funds or institutions are positioned in Bitcoin or Ethereum' and specifies the output: 'Returns net positions in contracts, week-over-week changes, open interest and notable extremes/streaks.' This distinguishes it from sibling tools like ETF flows or liquidations.

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 provides an explicit when-to-use: 'Call this when the user asks... about the CFTC Commitments of Traders report.' It also explains what the tool returns, but does not mention when not to use it or suggest alternative tools, so it falls short of a 5.

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