Index Option Chain (IV, Greeks, OI by strike)

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

Annotations already declare readOnlyHint=true and idempotentHint=true, but the description adds critical behavioral context: it is an end-of-day snapshot (not streaming), explains percent units, and details null handling (nulls are unpublished, never zero) and specific flags like iv_unsolved, illiquid, and pcr_undefined. This goes far beyond what annotations provide.

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?

Though lengthy, the description is densely packed with essential operational details — purpose, usage, caveats, units, null handling, and presentation rules — all front-loaded and logically ordered. Every sentence earns its place given the tool's complexity; there is no redundancy.

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?

With no output schema, the description compensates by naming key output fields (snapshot_ts, iv_pct, atm_iv_pct, atm_offset, available_expiries) and explaining their meaning. It also covers edge cases like null flags and instructs proper presentation. An agent has everything needed to call and interpret correctly.

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 coverage is 100% for all 5 parameters, so the description doesn't need to explain them. The description does reference output fields (snapshot_ts, iv_pct, atm_offset) but not input parameters. The baseline of 3 applies because the schema already documents parameters fully; the description adds no extra parameter-level nuance.

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 retrieves an INDEX OPTION CHAIN with IV, Greeks, bid/ask, and open interest by strike. It also distinguishes it from siblings by explicitly mentioning that get_option_iv_history covers stocks, making the scope 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 provides explicit when-to-use guidance with example queries ('show me the NIFTY option chain', 'what is the ATM IV', etc.) and explicit when-not-to-use (stock options) with an alternative tool named. This fully routes the agent to the correct tool.

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