mb_place_order

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

No annotations are provided, so the description carries the full burden. It discloses the critical safety behavior: the two-step confirm flow (confirm=false returns preview, confirm=true executes). It also explains that cost auto-calculates quantity. While it doesn't cover permissions or error handling, it provides key behavioral context beyond a simple 'place order' statement.

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?

The description is well-organized with sections for confirmation flow, cost usage, and order type definitions. Every sentence provides value, and the structure makes complex information scannable. The length is appropriate for the tool's complexity.

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 tool with 10 parameters and four order types, the description covers the essential usage patterns and safety flow. It lacks details on preview output format and whether confirm=true must reuse the exact same parameters, but these are minor given schema descriptions of conditional requirements and the clear step-by-step confirmation instructions.

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%, but the description adds substantial meaning beyond schema definitions: explains 'cost' vs 'qty' trade-off, defines order types and which parameters are relevant (e.g., 'stoplimit triggers a limit order when stopPrice is reached'). This significantly enhances parameter understanding.

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 the specific action: 'Place a buy or sell order on Mercado Bitcoin' and lists supported order types (market, limit, stoplimit, post-only). This clearly distinguishes it from sibling tools like mb_cancel_order or mb_get_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?

Provides explicit guidance on the two-step confirmation flow and explains when to use 'cost' instead of 'qty' for market buy orders. Also defines each order type with usage semantics. However, it does not explicitly mention when not to use this tool or direct users to alternative tools, but the context is clear.

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