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

No annotations are provided, so the description carries the burden. It discloses the authentication/payment requirement (bearer token or per-call payment), which is useful. However, it does not mention whether the operation is read-only, any side effects, rate limits, or error behavior. For a data-retrieval tool, the read-only nature is implied but not stated.

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 a single dense sentence, but it packs a lot of value. It front-loads the payment requirement, which might be secondary to the core purpose, but the overall length is appropriate. The structure could be improved by separating payment info from functional behavior, but it remains concise and complete.

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?

An output schema exists, so return-value documentation is not required. The description covers the tool's output content, parameter constraints, and payment/auth. For a tool with two optional parameters, this is sufficient. It lacks details on error scenarios or rate limits, but those are not critical for a read-like query 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 0%, so the description must compensate. It explains 'window' in hours with default and max, and clarifies 'chain' by stating omission returns all nine. It does not list each chain value, but the schema's enum already does that, so the description adds meaningful usage context beyond the schema.

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 clearly states the tool's function: it returns open interest per chain with latest value, start-of-window value, percent change, high/low, and a sampled series. This is specific and distinguishes it from siblings like prices or candles, which are about other market data. The verb is implicit but the resource and data points are explicit.

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?

Provides concrete usage guidance: 'window in hours, default 24, max 720' and 'Omit chain for all nine'. These are actionable parameter constraints. However, it does not explicitly state when to use this tool versus alternatives, though none of the siblings directly compete, so the lack of exclusion is acceptable.

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