Cancel an open order (dry run by default)

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

Annotations already declare destructiveHint=true, idempotentHint=false and readOnlyHint=false, so the mutation profile is known. The description adds genuinely useful context the annotations do not: dry run is the default, cancellation is not exempt from confirmation, and the risk rationale (cancelling a stop-loss can increase risk). It stops short of describing failure modes such as an already-filled order or what a dry run returns.

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?

Three short sentences, front-loaded with the action and then the safety-critical dry-run default. Every clause carries information; only the parenthetical risk note competes slightly with the main instruction.

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?

No output schema exists, so the description would ideally say what a dry run returns and what happens on failure. It does cover the confirmation-token workflow and the risk note, which are the main things an agent needs before calling a destructive tool, but the return/error side is left implicit.

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 80% and the schema already explains dry_run, confirmation_token, variety and parent_order_id in detail, so the baseline is 3. The description adds the cross-cutting rule that caps do not apply to cancellations, which is not encoded in any parameter schema and clarifies that margin/limit checks are irrelevant here.

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?

States a specific verb and resource ('Cancel an open or pending order') and immediately narrows the scope to open/pending orders, which distinguishes it from read-side siblings like get_orders and get_order_history. It does not explicitly contrast with modify_order or delete_gtt_order, so sibling differentiation is partial rather than explicit.

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?

Gives clear operating context: it works on open or pending orders, runs as a dry run by default, and requires the same confirmation step as place_order. It never states when an agent should prefer modify_order over cancelling, but the preconditions and the default-safe invocation path are spelled out.

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