gpt_informal_prover
AI agents invoke gpt_informal_prover to trigger actions in Lean Lsp. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
Based on the server context (agentic interaction with Lean theorem prover) and sibling tool 'gemini_informal_prover', this tool likely invokes a GPT model to generate informal proofs and interact with the Lean prover, which constitutes executing external operations. The empty description lowers confidence significantly.
From the tool's definition Tool name 'gpt_informal_prover' and server context involving Lean theorem prover via LSP; description is empty and uninformative.
Documented attack patterns abuse exactly the kind of access gpt_informal_prover gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Lean Lsp, and nothing reaches the server without passing your rules. This is the rule we recommend for gpt_informal_prover:
{
"version": "1",
"default": "deny",
"tools": {
"gpt_informal_prover": {
"limits": [
{
"counter": "gpt_informal_prover_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}gpt_informal_prover stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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gpt_informal_prover. It is categorised as a Execute tool in the Lean Lsp MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Lean Lsp MCP server in PolicyLayer and add a rule for gpt_informal_prover: 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 Lean Lsp. Nothing to install.
gpt_informal_prover 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 gpt_informal_prover 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 gpt_informal_prover. 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.
gpt_informal_prover is provided by the Lean Lsp MCP server (project-numina/lean-lsp-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Lean Lsp, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
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