get_historical_chain

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

With no annotations, the description carries the full burden and does disclose key behavioral traits: it is an EOD snapshot, historical depth goes back years, and it returns an end-of-day chain snapshot. It does not mention potential limitations like adjusted prices or data source specifics, but the core behavior is transparent and matches what an agent would expect from a historical query tool.

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 well-structured and appropriately sized. It opens with the core statement, adds an illustrative sentence, provides clear when-to-use bullets, and ends with an Args/Returns section. Every sentence serves a purpose, and the organization is front-loaded with the most important information.

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 tool with no output schema and no annotations, the description covers all necessary aspects: purpose, usage context, parameter explanations, return value, and historical scope. It fully equips an agent to select and invoke the tool correctly, including clarifying that it is an EOD snapshot and how trade_date differs from expiration.

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 0%, so the description must compensate. It provides an Args section with concise definitions: ticker as 'Stock symbol', expiration as 'Expiration date YYYY-MM-DD', and trade_date as 'The historical date to snapshot YYYY-MM-DD'. These add format and meaning beyond the schema's bare titles, especially for dates, though ticker's definition merely restates its meaning.

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 states a specific verb+resource: 'Get the options chain as it looked on a past trading day (EOD snapshot).' It distinguishes from siblings by emphasizing the historical nature and lists specific use cases, making the purpose clear and unique among sibling tools like get_options_chain.

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 usage guidance with a bulleted list ('Use this tool when the user asks about...') covering common scenarios. It does not explicitly name alternative tools or state when not to use, but the historical focus clearly separates it from current-chain tools. The guidance is strong but lacks direct exclusion/alternative references, so 4 is appropriate.

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