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

No annotations are supplied, so the description carries the full burden. It does contribute one genuinely useful behavioral fact — that in paper mode cancellation executes immediately — but omits what happens to already-filled orders, whether cancellation is idempotent, required permissions, and any failure modes for a mutation tool.

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 short sentences, zero filler, with the primary action front-loaded and the paper-mode caveat trailing as a secondary note. Nothing could be removed without losing 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?

For a single-parameter cancel tool with no output schema and no annotations, the description covers purpose and one mode-specific behavior, which is close to adequate. It still leaves the agent guessing about error handling on non-resting orders and what the call returns, gaps that matter more here because no structured field fills them.

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 0% and the lone parameter is bare ('order_id' with no description), so the description must compensate. It does add real meaning by clarifying the id is a ledger id, ruling out a client-supplied order reference, but gives no format or example.

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 a resting order') plus the identifier basis ('by ledger id'), which distinguishes it from place_order/submit_order and list_orders among the siblings. It stops short of distinguishing itself from close_position, which could also read as exiting an 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 word 'resting' implies the applicable case implicitly, but there is no explicit when-to-use, when-not-to-use (e.g., already-filled or partially-filled orders), or named alternative. An agent must infer the boundary conditions itself.

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