Execute a read-only smart contract call on Mezo. Returns the hex-encoded return data. Use this to read contract state without sending a transaction.
Part of the Boar blockchain MCP (advanced) server.
Free to start. No card required.
AI agents invoke mezo_call to trigger processes or run actions in Boar blockchain MCP (advanced). Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.
mezo_call can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. PolicyLayer enforces rate limits and validates arguments to keep execution within safe bounds.
Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.
{
"version": "1",
"default": "deny",
"tools": {
"mezo_call": {
"limits": [
{
"counter": "mezo_call_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}See the full Boar blockchain MCP (advanced) policy for all 13 tools.
These attack patterns abuse exactly the kind of access mezo_call gives an agent. Each links to the full case and the policy that stops it:
Other execute tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Execute a read-only smart contract call on Mezo. Returns the hex-encoded return data. Use this to read contract state without sending a transaction.. It is categorised as a Execute tool in the Boar blockchain MCP (advanced) MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Boar blockchain MCP (advanced) MCP server in PolicyLayer and add a rule for mezo_call: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Boar blockchain MCP (advanced). Nothing to install.
mezo_call is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the mezo_call rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for mezo_call. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
mezo_call is provided by the Boar blockchain MCP (advanced) MCP server (boar-network/blockchain-advanced). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 13 Boar blockchain MCP (advanced) tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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