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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds 'Read-only: no transaction is ever sent,' which reinforces but doesn't meaningfully extend the annotations. It also mentions the technical method (eth_call state override), but this is more about implementation than behavior. No contradiction with 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?

Two sentences with no filler. The primary purpose and the key safety fact (read-only) are front-loaded. Every word earns its place, and the structure is immediately scannable.

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 simple, has an output schema, and all parameters are documented. The description conveys the intended use, the method, and the non-destructive nature. Nothing critical for an agent to invoke it correctly is missing. It could mention edge cases (e.g., token decimals), but the schema already handles that.

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 every parameter already has a description. The tool description adds no additional parameter-specific meaning; it only frames the overall purpose. Per the rubric, when schema coverage is high, a score of 3 is appropriate without further elaboration.

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 a specific verb ('simulate') and resource ('a wallet's ERC-20 balance') with the context of a hypothetical trade and the method (eth_call state override). It is unambiguous and not a tautology, but it does not explicitly distinguish itself from sibling tools like evaluate_trade, so it loses the top point.

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 implies the use case: simulating a balance after a hypothetical trade. It provides context but gives no explicit guidance on when to use this tool over alternatives or when not to use it. No alternatives are mentioned, so the agent must infer the appropriate context from the wording alone.

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