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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds meaningful behavioral context beyond that: refresh cadence ('Every Friday at 15:30 ET'), the Tuesday cutoff, weekly snapshot nature, and an API key requirement. These details help agents set expectations and handle failures.

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 compact (~70 words) yet information-dense. The core action and use-case triggers are front-loaded, with cadence, API key, and supported currencies efficiently appended. No sentence is wasted or redundant.

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?

Given the output schema exists, the return shape does not need to be described. The description covers data content, update schedule, cutoff times, API key requirement, and supported currencies, which is complete for a simple 3-parameter, read-only lookup 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%, so the schema already documents every parameter, including formats, defaults, and supported values. The description adds no deeper parameter semantics beyond restating the supported currencies, so the baseline of 3 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?

States a specific verb ('Get'), a precise resource (weekly CFTC COT positioning data for a currency's FX futures contract on the CME), and the domain (speculator positioning). This clearly distinguishes it from broader data tools like forecast or commodities, and its focus on FX futures makes it distinct from sibling tools.

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?

Gives explicit use-case triggers: 'speculator positioning, non-commercial longs vs shorts, hedge-fund FX positioning, or wants to gauge sentiment extremes.' It does not name alternatives or explicitly state when not to use it, but the context is clear enough for an agent to select it correctly among many siblings.

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