Open position

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

Annotations already indicate destructive/world-changing behavior. The description adds that it respects configured trading mode (demo/real), providing useful behavioral context beyond what annotations offer. No contradictions.

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?

Two succinct sentences, front-loaded with the primary action. Every word serves a purpose; no fluff.

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?

While the description covers the main operation, it omits expected return value (e.g., trade confirmation) and does not mention potential fees or constraints, leaving some gaps for an 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?

Schema coverage is 100% with clear descriptions. The description reiterates the mutual exclusivity of amount/units, which is already in the schema, adding minimal new semantic value.

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 uses a specific verb ('Open') and resource ('position on an instrument'), clearly distinguishing it from siblings like 'place_limit_order' or 'close_position'. It also adds context about trading mode.

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 key constraint ('Provide exactly one of amount or units') and mentions trading mode, but does not explicitly compare to alternative tools like limit orders or specify when to use this market order type versus others.

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