microloop 0.1.9

Ultra-fast runtime safety layer for autonomous agents — detects agent tool call loops before they burn API credits

Microloop for Python

Rust-backed loop detection for AI agents. Blocks repetitive tool calls before they burn API credits.

See the full demo: python3 scripts/demo_loop.py

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The $500 Loop of Death

Every AI agent developer knows this pain: You build an autonomous agent, run it overnight, and wake up to a $500 OpenAI bill.

What happened? The agent tried to write a file. The tool returned an error. The agent retried with the exact same arguments. It failed again. It spent the next 6 hours in a tight loop, burning millions of tokens, accomplishing nothing.

Microloop stops this. It detects and blocks agent loops in under 200 nanoseconds.

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Blind Counters vs. Microloop

Traditional frameworks rely on step counters (max_iterations = 10). Step counters are blind.

The Blind Counter	The Microloop Shield
Blocks valid workflows. If a complex 15-step plan is working perfectly, a limit of 10 kills it.	Unlocks infinite steps. Your agent can run 100 steps if it's making progress.
Allows expensive waste. A 2-step loop will run 5 more times before hitting a max_iterations = 10 limit.	Fails fast. Blocks the loop at step 2—the very first redundant repeat.

Counters measure quantity. Microloop measures redundancy.

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Core Pillars

1. Zero-Latency Fast Path

Runs locally in-process. Hashes tool calls and checks for repetitive trajectories in under 200 nanoseconds using the native Rust core.

2. Smart Volatile Field Masking

Automatically detects high-entropy fields (like req_id: "9831" changing to req_id: "9832") and masks them, catching loops even when arguments aren't 100% identical.

3. Adaptive Thresholding

If a tool call returns an error, the agent is in a high-risk state. Microloop automatically tightens its repetition thresholds on failure.

4. Horizontal Redis Sync

Plug in a Redis backend to share blocklists and loop states across a cluster of agent workers.

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Quick Start

Installation

pip install microloop

Basic SDK Usage

from microloop.microloop_core import Microloop

engine = Microloop("max_repeats: 3")

result = engine.verify("write_file", '{"path": "/tmp/x.txt"}')
if result > 0:
    print("Action blocked! Forcing agent to pivot.")

LiteLLM Integration

import litellm
from microloop.integrations import MicroloopLiteLLMGuardrail

guardrail = MicroloopLiteLLMGuardrail(max_repeats=3)
litellm.callbacks = [guardrail]

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Performance Benchmarks

Benchmark	Microloop	Prompt-Based Guardrails
Check Latency	197 nanoseconds	~1.5 seconds (API call)
Operational Cost	$0.00 (Local execution)	~$0.01 per step (Token burn)
Execution Safety	100% Deterministic	Probabilistic
Memory Footprint	< 10 MB	N/A
Throughput	5,000,000+ checks/sec	~50 checks/sec

Benchmark	Iterations	Per Op	Ops/s
verify_e2e	100,000	197 ns	5,071,573
cold_start_verify	10,000	42,460 ns	23,551
compress_short_fastpath (<512 bytes)	200,000	50 ns	19,905,780
oscillation_detect	500,000	3,049 ns	327,887
compress_git_diff	50,000	6,811 ns	146,821
compress_build_output	50,000	15,393 ns	64,961
compress_json_array	50,000	33,993 ns	29,417
compress_source_code	50,000	164,475 ns	6,080
mixed_workload (verify + compress, 8 tools)	10,000	1,094,099 ns	914

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Configuration

max_repeats: 3          # Max identical calls before blocking
history_window: 8       # Rolling window size
strictness: Balanced    # Lenient, Balanced, or Strict
tools:
  - name: execute_command
    trajectory_gate:
      volatile_fields: ["timestamp", "session_id"]

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Security

• No tool data or code ever leaves your environment.
• Zero external API calls.
• Apache 2.0 Licensed.