AI agents use tell to create or update resources in Optuna MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Optuna MCP Server environment.
The 'tell' tool reports (writes) the outcome of a trial back to the optimization study. This is a reversible data write operation that modifies study state by recording trial results. It does not execute arbitrary code, delete data, or involve financial transactions. Misuse could corrupt optimization results but is recoverable.
From the tool's definition "Report the result of a trial" — this writes/updates trial result data into an Optuna study
Documented attack patterns abuse exactly the kind of access tell gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Optuna MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for tell:
{
"version": "1",
"default": "deny",
"tools": {
"tell": {
"limits": [
{
"counter": "tell_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}tell stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Report the result of a trial. It is categorised as a Write tool in the Optuna MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Optuna MCP Server MCP server in PolicyLayer and add a rule for tell: 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 Optuna MCP Server. Nothing to install.
tell is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the tell 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 tell. 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.
tell is provided by the Optuna MCP Server MCP server (optuna/optuna-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 26 Optuna MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
26 Optuna MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.