Simulate EVM Transaction

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

Annotations already provide readOnlyHint, idempotentHint, etc. Description adds behavioral details: uses Foundry cast, returns revert reasons and error handling. No contradiction.

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?

Well-structured with sections: brief purpose, arguments, returns, examples, error handling. Every sentence is informative, no fluff.

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?

Explains return format and error handling. Context signals indicate an output schema exists (though not shown), so description complements it well. Could be 5 if output schema were explicitly provided.

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 has 100% coverage, but description adds examples and format hints (e.g., target must be 0x-prefixed, args space-separated). This provides practical guidance 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?

Clearly states it simulates a read-only call via eth_call, returns decoded results or revert reasons, and explicitly says it does NOT submit a real transaction. Differentiates from sibling tools like evm_trace_call by focusing on simulation.

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 clear context: simulates via eth_call, no real transaction. Includes examples for common use cases. Could be improved by explicitly stating when not to use (e.g., for write operations), but siblings are distinct enough.

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