Option bars

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

Annotations already cover read-only/idempotent/non-destructive/open-world, so the bar is lower. The description adds real behavioral context the annotations cannot: units (premium per share USD, volume in contracts) and the truncation contract — large results are stored and returned as a result_id to fetch via results_query.

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?

Three tight sentences, front-loaded with the resource and scope, no filler. Minor duplication of defaults that already live in the schema keeps it short of a 5.

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?

No output schema exists, so naming the fields (OHLCV), units, and the result_id handoff covers the essential return semantics. Pagination and sort are left to the schema, which is acceptable given 100% schema coverage.

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 100%, so the schema fully documents all seven parameters, including start/lookback mutual exclusion and pagination. The description restates the timeframe/lookback defaults and the start-or-lookback choice, adding little beyond the schema; baseline 3 applies.

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?

States a precise verb+resource: 'Historical OHLCV bars for option contracts by OCC symbol.' The 'historical' + 'option contracts' framing separates it from the latest/snapshot siblings (options_latest_quotes, options_snapshots) and from equity bars (market_bars) without needing to name them.

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?

Usage context is implied by the OHLCV/window framing, and it helpfully routes large responses to results_query. But it never states when to pick this over options_chain, options_trades, or market_bars, and gives no exclusions or prerequisites.

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