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

With no annotations available, the description carries the transparency burden and handles it well: it discloses the required ChainHelix API key/bearer or per-call fee, describes the output data shape in detail, and explains default window and chains. It could add response format or rate-limit details, but no contradictory or unclear safety behavior exists.

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?

Every sentence carries relevant information, but the long billing phrase at the start delays the core purpose and the output details are densely packed into comma-separated clauses. The description is compact, but not as front-loaded or scannable as it should be.

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 simple, non-destructive fetch tool with no output schema, the description covers the most important required details: auth/payment, output fields, chain selection, and window defaults. The main missing piece is the definition of 'sampled series' frequency and the exact response format, but the tool remains callably complete.

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 input schema only lists chain and window without descriptions, so the description adds significant meaning: it specifies window units, default, maximum, and the behavior of omitting chain. The chain enum values themselves are still left to the schema, but the description compensates for the main conceptual gaps.

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 defines the tool as open interest per chain and enumerates the exact returned fields: latest value, start-of-window value, change percent, high, low, and a sampled series. It lacks a strong verb like 'returns' or 'gets,' and it does not explicitly contrast with sibling tools, but the resource and output are unambiguous.

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 gives operational guidance such as 'window in hours, default 24, max 720' and 'Omit chain for all nine,' plus an explicit authentication or payment requirement. However, it does not say when to prefer or avoid this tool versus related sibling metrics tools, so the usage context is mostly implied rather than stated.

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