Sabrix-bench: Fast MCP inspector and agent loop latency profiler in Rust

Sabrix released sabrix-bench, an open-source Rust CLI and benchmark harness for Model Context Protocol (MCP) traffic inspection and agent loop latency profiling, claiming sub-2-microsecond per-turn latency with zero network egress. The tool benchmarks multi-turn agent loops, flags dangerous tool mutations via nine deterministic security rules, and compares its In-VPC engine against legacy Python/Node proxies (35ms per turn) and SaaS AI firewalls (120ms per turn, adding 3.6 seconds over a 30-turn loop).

Ultra-fast, zero-bloat developer CLI and benchmark harness for Model Context Protocol MCP traffic inspection and agent loop latency profiling. Developers building autonomous AI agents locally lack visibility into raw Model Context Protocol MCP JSON-RPC tool traffic and have no lightweight way to measure per-turn serialization and proxy latency overhead. Legacy approaches introduce massive performance and security taxes: Legacy Python / Node Proxies: Add 30ms – 50ms of serialization and runtime tax per tool call. SaaS AI Firewalls: Incur 100ms – 250ms of WAN network latency, TLS handshakes, and third-party cloud data egress per turn.- Over a 30-turn agent loop , legacy firewalls add 3.6+ seconds of dead wait time and leak raw database queries and internal system commands outside your perimeter. sabrix-bench gives you real-time visibility into your local MCP tool calls and benchmarks your agent loops in microseconds $< 2\ \mu\text{s}$ with zero network egress . Clone the repository and install the binary cargo install --path . Or run directly with Cargo: cargo run -- --help Inspect JSON-RPC 2.0 requests tools/call , resources/read , tools/list and flag dangerous tool mutations destructive shell commands, SQL injections, leaked credentials . sabrix-bench trace --demo sabrix-bench trace -p '{ "jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": { "name": "database query", "arguments": { "sql": "DROP TABLE users; --" } } }' cat mcp message.json | sabrix-bench trace Simulate multi-turn autonomous agent loops to measure local parsing overhead, memory serialization, and latency percentiles Run a 30-turn benchmark with real-time progress sabrix-bench bench --turns 30 Benchmark larger context payloads 10x scale sabrix-bench bench --turns 50 --scale 10 Output machine-readable JSON for CI/CD pipelines sabrix-bench bench --turns 20 --json Output a side-by-side architectural comparison contrasting In-VPC embedded engines against legacy proxies and remote SaaS firewalls. sabrix-bench compare | Layer / Architecture | Per-Turn Latency | 30-Turn Loop Delay | Egress & Privacy | Memory Footprint | |---|---|---|---|---| Sabrix In-VPC Engine | 0.002 ms < 2 µs | < 0.06 ms | 100% In-VPC Zero Egress | < 15 MB | Legacy Python / Node Proxy | 35.0 ms | +1.05 seconds | Local Cluster | 150 MB – 400 MB | SaaS AI Firewall | 120.0 ms | +3.60 seconds | Full Payload Egress | N/A Cloud SaaS | sabrix-bench evaluates deterministic security rules locally in sub-microsecond time: : Destructive Filesystem Operations MCP-SEC-001 rm -rf , mkfs , dd , chmod 777 : Remote Code Execution / Reverse Shells MCP-SEC-002 curl | bash , nc -e , /dev/tcp/ : Destructive SQL Mutations & Injections MCP-SEC-003 DROP TABLE , TRUNCATE , DELETE FROM , WHERE 1=1 : Leaked API Keys & Secrets OpenAI MCP-SEC-004-007 sk- , GitHub ghp , AWS AKIA , PEM Private Keys : Sensitive Path Egress MCP-SEC-008 /etc/passwd , ~/.ssh/id rsa , ~/.aws/credentials , .env : Unconstrained Arbitrary Execution Tool Invocations MCP-SEC-009 Enforce zero-egress In-VPC MCP security with millisecond-grade deterministic policy control: 👉 Deploy Sabrix In-VPC Gateway https://sabrix.ai Licensed under either of Apache License, Version 2.0 /Pro-Kla/sabrix-bench/blob/main/LICENSE-APACHE or MIT license /Pro-Kla/sabrix-bench/blob/main/LICENSE-MIT at your option.