Close a position

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

With no annotations, the description carries the full burden and does well: it discloses that the order is reduce-only and crosses the spread (i.e. it will take liquidity rather than rest), and that it is exempt from the loss-limit halt. It does not cover failure modes (e.g. no open position), irreversibility, or what the response contains, which keeps it short of a 5.

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 sentences, zero filler, and the core action is front-loaded ahead of the permission nuance. Each sentence earns its place.

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 mutation tool with no annotations and no output schema, the description supplies the essentials an agent needs to act safely: the order type, the price behavior, and the halt exemption. Remaining gaps are edge cases (no position to close, partial-fill behavior) rather than core missing context.

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 50%: 'reason' is documented in the schema, but 'symbol' has no description anywhere. The prose clarifies scope ('in one symbol', closing the whole position rather than partially), which adds a little, but it does not compensate for the undocumented symbol parameter.

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 and resource ('flatten the whole position in one symbol') and names the execution mechanism ('a reduce-only order that crosses the spread'), which implicitly distinguishes it from place_order. An agent can tell exactly what this does without opening the schema.

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?

It gives a concrete use condition: this is a risk-reducing action, so it remains permitted even when the daily loss limit has halted new trading. That is real routing guidance, though it never names place_order as the alternative for opening/increasing exposure, so the when-not-to-use side is left to inference.

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