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

Provides rich context beyond annotations: execution model (10 bps per side, close execution, no slippage), sample vs. holdout distinction, explicit failure behavior, daily quota of 60, and a privacy warning that the server may retain the submitted script. This is exactly the kind of behavioral detail an agent needs.

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 dense but front-loaded with the core purpose. It is a single long sentence with multiple clauses; a bullet list would improve readability, but every clause 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?

Given no output schema is mentioned in the context (it says has output schema, but description needn't explain return values extensively), the description covers execution rules, quota, privacy, and failure modes. It is complete enough for an agent to call 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 coverage is 100% and the single parameter is fully described there. The description adds no further syntax details, so baseline 3 is appropriate.

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 (backtest) and resource (ArenaScript strategy via Rust Lab engine), and distinguishes itself from siblings like backtest_arenascript by naming the exact engine and rules. The scope is unambiguous.

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?

Clearly says when the engine refuses or is unavailable it fails explicitly, and warns not to submit private strategies. However, it does not explicitly name alternatives or say when to use this vs. backtest_arenascript or invent_and_backtest.

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