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

The annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds valuable behavioral context beyond that: it validates and sizes the order (fresh est. entry, size after rounding, est. liquidation, TP/SL sanity, MCP caps) and shows a proposal card. This is useful context without contradicting the annotations.

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 two dense sentences with no filler. It front-loads the most important usage instruction ('Use this BEFORE place_order...') and puts the safety note ('Read-only and always safe to call') near the end. Every phrase 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 tool with 9 parameters, no output schema, and no nested objects, the description covers all essential context: when to call it, what it does, what it doesn't do, and what happens next. The proposal card is described, and the follow-up path to place_order is explicit. An agent has everything needed to invoke it correctly.

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 description coverage is 100%, so all 9 parameters already have descriptions in the schema. The tool description adds no parameter-specific meaning beyond saying that the same arguments should be passed to place_order. Per the calibration baseline, 3 is appropriate when the schema carries the semantic load.

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 names a specific action (preview an order before placement) and a specific resource (the order being opened). It explicitly differentiates itself from place_order by stating it 'validates and sizes the order' and does so 'WITHOUT placing anything'. This makes the tool's role unambiguous among its siblings.

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 description gives an explicit directive: 'Use this BEFORE place_order whenever the user wants to open a position'. It also provides the follow-up action ('If the user confirms, call place_order with the same arguments'), making the workflow clear. No alternative or exclusion is left ambiguous.

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