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Diogenes Agent Guardrails & Sandbox MCP

io.github.stand-out-of-my-sun/diogenes-agent-guardrails-mcp · v1.0.0

Measured by MCP Station

Instruction-like text was found in audit_outbound_egress_url, verify_agent_command_safety. This is a pattern match, not a verdict. What we look for

Description written by the publisher, not verified

Autonomous agent guardrails, bash sandboxing, MCP rugpull diffing & prompt firewalls.

Connect

claude mcp add --transport http diogenes-agent-guardrails-mcp https://diogenes-micro-gateway.corinth.workers.dev/mcp/agent-guardrails

{
  "mcpServers": {
    "diogenes-agent-guardrails-mcp": {
      "url": "https://diogenes-micro-gateway.corinth.workers.dev/mcp/agent-guardrails"
    }
  }
}

Tools as reported by the server

• verify_agent_command_safety
  Evaluates untrusted agent prompts, bash commands, and tool arguments to block prompt injection, destructive shell commands, and private-key exfiltration. Use when screening a general shell command or user prompt before agent execution; for statically validating SQL database queries at the AST level,
• validate_sql_query_ast
  Performs static AST syntax tree parsing on SQL statements to verify strictly read-only SELECT clauses and reject mutations, stacked queries, or comment bypasses. Use when verifying that an agent-authored SQL statement is strictly read-only before running it on a database; for screening non-SQL bash
• execute_python_sandbox
  Audits Python source code for forbidden syscalls (os, subprocess, socket, open, eval) inside an AST-governed WebAssembly sandbox with no host filesystem access. Use when executing LLM-generated Python snippets safely; for checking shell commands without executing code, use verify_agent_command_safet
• audit_mcp_server_manifest
  Scans an external MCP server's initial tools/list manifest to detect tool-name shadowing (read_file, bash) and hidden prompt-injection directives in descriptions. Use when vetting a newly discovered third-party MCP server before mounting it into an agent session; for comparing a previously pinned MC
• detect_mcp_schema_rugpull
  Computes structural diffs between a pinned baseline MCP tools/list snapshot and a live server response to catch mid-session description or schema tampering. Use when verifying that a connected MCP server has not mutated its tool definitions mid-session; for performing a first-time static security au
• validate_mcp_sampling_request
  Audits inbound MCP sampling/createMessage callbacks from connected servers to block cross-server context snooping (includeContext='allServers') and token quota hijacking. Use when filtering a connected MCP server's request to sample the host LLM; for scrubbing text returned from a standard synchrono
• sanitize_tool_output_stream
  Sanitizes untrusted external tool or web-scrape outputs by stripping invisible Unicode Tag characters (U+E0000), neutralizing Markdown tracking image beacons, and defusing indirect prompt overrides. Use when cleaning raw third-party tool outputs or scraped web text before inserting it into the LLM c
• redact_sensitive_pii
  Redacts emails, phone numbers, SSNs, credit cards, API keys, and crypto private keys from text before logging or external transmission. Use when stripping personal data or secret credentials from prompts, logs, or outbound messages; for neutralizing indirect prompt injections and invisible Unicode i
• detect_agent_action_loop
  Analyzes an agent's recent tool-call trace to detect identical retry spins, A/B state oscillation, and runaway token burn. Use when monitoring multi-step agent execution loops to decide whether to continue or halt and escalate; for inspecting a single command payload for security threats before exec
• verify_a2a_agent_card
  Verifies a remote agent's A2A /.well-known/agent.json discovery card, checking JWS/DID signature binding, endpoint HTTPS enforcement, and capability spoofing. Use when authenticating a peer autonomous agent before delegating subtasks or exchanging payments over A2A; for auditing an MCP tool server's
• audit_outbound_egress_url
  Static validation firewall for outbound network destination URIs against cloud metadata IP addresses (169.254.169.254), RFC 1918 private IP blocks, and query-string secret exfiltration before agent dispatch. Use when validating a user-supplied or tool-supplied URI destination before network dispatch
• audit_response_factuality
  Cross-references factual claims, numbers, and citations in a draft agent response against retrieved source passages to flag unsupported hallucinations before delivery. Use when verifying that a generated answer is 100% grounded in source evidence before returning it to the user; for scrubbing inboun

Tool changes

• 2026-10-22: verify_agent_command_safety, validate_sql_query_ast, execute_python_sandbox, audit_mcp_server_manifest, detect_mcp_schema_rugpull, validate_mcp_sampling_request, sanitize_tool_output_stream, redact_sensitive_pii, detect_agent_action_loop, verify_a2a_agent_card, audit_outbound_egress_url, audit_response_factuality
• 2026-10-21: code_sandbox, guardrail_verify, scrub_pii, mcp_rugpull_diff, tool_output_firewall, mcp_sampling_guard, agent_loop_circuit_breaker, agent_mcp_manifest_auditor, agent_sql_guard

Repository · Website · JSON · Text for agents · Registry updated 2026-10-20