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

Annotations already indicate readOnlyHint=false and destructiveHint=false, but the description goes well beyond them by explaining that no real funds move, prices are server-side and cannot be caller-supplied, rules are enforced server-side, and error responses are formatted as {"error": "..."}. It also clarifies the api_key purpose and that reason appears in trade history, offering rich behavioral context.

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 long but every sentence adds distinct value: purpose, safety, pricing, parameter explanations, rules, and error handling. It is front-loaded with the core action and structured cleanly. No filler or redundancy.

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?

The tool is moderately complex with no output schema, and the description covers key behavioral aspects: no real funds, server-side pricing, parameter meanings, and server-enforced rules. It even explains error responses. However, it does not describe the success response format or explicitly explain `ticker`, leaving a minor completeness gap.

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 0%, so the description must compensate. It explains api_key (personal otto_pk_ key), side (buy | sell), qty (shares), and reason (shows in trade history). However, it omits the required `ticker` parameter entirely, which is a small but notable gap. The explanation of the other parameters adds meaningful value beyond the schema.

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 clearly states the tool's purpose with a specific verb and resource: "Place a PAPER fill in Otto's trading competition on behalf of the key's owner." It also differentiates this from real trading by emphasizing "No real funds move" and that pricing is server-side. This makes it distinct from sibling tools like execute_onchain_swap.

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 provides clear context that this is for paper trading in a competition, with rules such as $10,000 budget, long-only, max $2,000 notional, 10 positions, and 40 trades/day. It does not explicitly name alternative tools or state when not to use it, but the paper-trading context and explicit constraints provide sufficient guidance.

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