get_historical_prices

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

No annotations are provided, so the description carries the full burden. It does not state whether the operation is read-only, what the return structure looks like, or any potential errors. It only lists parameters, offering minimal behavioral insight beyond the schema itself.

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 concise and well-structured, opening with a clear one-line purpose and then listing parameters in a simple, scannable format. Every line adds value with no wasted words.

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 tool's simplicity and the presence of an output schema, the description adequately covers the essential aspects: what the tool does, the parameters, and a prerequisite link to list_sessions. It lacks explicit edge-case handling, but for this straightforward read operation it is sufficiently complete.

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?

With 0% schema description coverage, the description compensates by explaining each parameter, including an example for contract_code and enumerating valid period values. This adds meaningful context over the bare schema.

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 'Get historical prices for an instrument' with a specific verb and resource. It distinguishes itself from sibling tools like get_holdings or get_transactions by focusing on historical price data, not current positions or transactions.

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 contextual usage hints by noting that 'session' comes from list_sessions, indicating a prerequisite and helping the agent understand the workflow. However, it does not explicitly mention alternatives or when-not-to-use, so it falls short of a 5.

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