Execute a read-only smart contract call on Mezo testnet. Returns the hex-encoded return data. Use this to read contract state without sending a transaction.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | Contract address | |
| data | Yes | ABI-encoded function call data | |
| from | No | Sender address (optional, for context) | |
| block | No | Block to query (default: latest) |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so the description's read-only statement is redundant. It adds the useful detail that the return data is hex-encoded, but it does not disclose other behaviors such as error handling, revert behavior, or block parameter defaults. Minimal incremental value beyond annotations gives a 3.
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 three short, front-loaded sentences with no unnecessary fluff. There is slight redundancy between 'read-only' and 'without sending a transaction', but it remains compact and easy to scan. It earns a 4 rather than a 5 due to the redundant phrasing.
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 simple read-call tool with full schema coverage and strong annotations, the description adequately covers purpose, return format, and usage context. It does not mention edge cases like revert behavior, but the tool's simplicity means this is not critical. Overall, it is complete enough for an agent to use 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?
Input schema descriptions cover 100% of the parameters, including 'to', 'data', 'from', and 'block', each with clear descriptions. The tool description does not add any additional parameter semantics, so the baseline of 3 applies.
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 uses a specific verb and resource: 'Execute a read-only smart contract call on Mezo testnet'. It clearly distinguishes from sibling tools by naming the network (Mezo testnet) and specifying read-only. The return format (hex-encoded) is also stated, which fully clarifies the tool's function.
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: 'Use this to read contract state without sending a transaction.' This tells the agent when to use the tool, but it does not mention alternatives or exclusions relative to sibling tools like mezo_testnet_multicall. Since it lacks explicit when-not-to-use guidance, it earns a 4.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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