get_fills_by_order

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

No annotations are present, so the description must carry behavioral transparency. It indicates a read operation (fetching fills) but does not mention any side effects, permissions, or response characteristics. Minimal detail beyond the core purpose.

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, front-loading the primary function (retrieve fills for an order) and its intended use. No superfluous words or redundant 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?

Given the simplicity of the tool (one parameter, no output schema), the description covers the basic purpose but omits details like return format, potential errors, or examples. It is adequate for a straightforward retrieval but lacks completeness for a robust agent.

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 only parameter, order_id, is mentioned in the description as 'one order' but not explicitly linked to the parameter name. The schema already provides the name, and the description adds little semantic value beyond that, such as expected format or constraints.

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 fetches fills for a specific order (a filtering subset of get_fills) and ties to the use case of computing average entry price. This distinguishes it from sibling tools like get_fills or get_order.

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 a use case (compute average entry price) but does not explicitly state when to use this tool versus alternatives like get_fills or get_order. The context is implied but not fully explicit.

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