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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=false), so the bar is lower. The description still adds real context beyond them: 'Simulated money only' and 'Requires an API key' tell the agent about the sandbox and auth requirement. It does not, however, explain non-idempotency (duplicate-order risk) or margin/leverage exposure.

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?

Front-loaded and tightly written, with the core behavior in the first sentence and routing/safety notes after. Every sentence carries information, though the misleading 'type' sentences spend space on a non-existent parameter.

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 an 8-parameter mutation tool with no output schema and 25% schema coverage, the description covers purpose, alternative, simulation scope, and auth, which is a fair amount. It falls short by not explaining the optional sl/tp/leverage/client_order_id parameters and by introducing a 'type' concept with no schema backing, leaving the agent to guess how limit vs stop is actually selected.

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 only 25% (8 params, just margin_usd and limit_price documented), so the description is expected to compensate and largely does not. Worse, it repeatedly references a 'type' parameter ('type "limit"' / 'type "stop"') that does not exist in the input schema, which could mislead an agent into passing a phantom argument. It does clarify limit_price semantics ('fills AT that price') but leaves sl, tp, leverage, and client_order_id unaddressed.

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 ('Place') and resource ('a resting order that fills only when the market reaches your price, and fills AT that price'), and immediately scopes it against the sibling paper_open. The limit-vs-stop entry semantics let an agent distinguish it from the other paper_* order tools.

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?

Explicitly routes the agent: 'To open right now use paper_open instead,' naming the alternative and the condition that selects it. It also explains when each order type applies (pullback entry vs breakout entry), so both the when-to-use and the alternative are spelled out.

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