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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful behavioral detail beyond that: iv_source labels, the special 'drifted first-passage formula' for touch, and the fact that approximations exist. It could be more concrete about what those approximations are, but overall it discloses methodology transparently.

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 dense but each sentence contributes distinct information: purpose, return values, data sources, special touch handling, and caveats. It is longer than some sibling descriptions, but the tool is inherently complex and the extra length is earned.

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 there is no output schema, the description does a good job explaining the key return elements (probability, edge, verdict, iv_source). It also covers asset fallback behavior and the touch edge case. Minor gaps: the actual approximation caveats are referenced but not enumerated, and exact response shape is not specified, but this still feels adequate for a read-only calculation 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?

The schema already covers all parameters 100%, so the baseline is 3. The description adds meaningful semantic value by explaining that market_yes_price enables the edge and cheap/rich/fair verdict, and that iv_source labels which volatility source was used. This goes beyond the schema's property descriptions.

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 opens with a specific verb+resource: 'Options/vol-implied fair value for a HIP-4 binary/range/touch PRICE market' and clearly states what it returns (risk-neutral probability, signed edge, verdict). It distinguishes itself from siblings like get_outcome_edges by emphasizing the vol-implied derivation rather than raw market edges.

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 clear context on when to use it: for HIP-4 price markets where you want IV-based fair value, with asset-specific guidance (BTC/ETH via Deribit IV smile, others via realized vol). It does not explicitly name alternatives or exclusions, but the conditions are strongly implied by the description and comparator list.

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