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

Annotations already declare the tool as read-only, idempotent, open-world, and non-destructive. The description adds valuable behavioral context beyond annotations: the $0.001/call cost and the default expiry selection rule.

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 front-loaded and compact: three short sentences cover purpose, default behavior, cost, and scope with no wasted text.

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 annotations, no output schema, and simple two-parameter input, the description is nearly complete. It lists the returned metrics but does not describe output shape or error behavior, leaving a small gap.

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 documents the expiry format and currency enum, while the description adds meaning by explaining that expiry defaults to the next expiry with open interest. It does not add further syntax details, but adequately compensates for the 50% schema coverage.

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 identifies the resource (one Deribit expiry) and the exact metrics returned (max pain, open interest, put/call ratio) for BTC or ETH. It distinguishes itself from broader siblings like options_summary by scoping to a single expiry, though it lacks an explicit action verb.

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?

It states the primary use case ('Use for one expiry's max pain and open interest only') and explains the default expiry behavior. It does not explicitly name an alternative sibling for broader options data, but the scoping is clear enough for selection.

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