Configure LoopGuard

A polling agent and a research agent can repeat for different reasons. Change settings when healthy runs trigger too much evidence, stuck runs take too long to flag, or you need a hard work limit.

Start with one application config

Save this as loopguard.yml:

live:
  max_steps: 40
  max_tool_calls: 15
  exact_threshold: 3
  exact_window: 12
  stall_patience: 4
  stall_fatal: false
  handoff_repeats: 2
  handoff_window: 16
  handoff_max_cycle_length: 5
  handoff_fatal: true
  semantic: false

check:
  fail_on:
    - looping
    - stalled
  max_steps: 40
  max_tool_calls: 15

Load the live section in your application:

from loopguard import LoopGuardCallbackHandler

handler = LoopGuardCallbackHandler.from_config("loopguard.yml")
handler.raise_error = True

Or use the check section with an exported trace:

python -m loopguard.check examples/sample_trace.json --config loopguard.yml

The trace command assumes a repository checkout. The sample deliberately includes a loop, so this check exits with code 1.

Choose limits and sensitivity

Setting	What it controls	When to change it
`max_steps`	Maximum recorded live events; exported steps in check mode.	Cap total work independently of loop detection.
`max_tool_calls`	Maximum recorded tool calls.	Limit repeated tool work.
`exact_threshold` / `exact_window`	Matching calls required inside a recent event window.	Allow longer healthy polling or catch exact loops sooner.
`stall_patience`	Identical consecutive observations required by `StallDetector`.	Your tools often return the same status while working.
`handoff_repeats` / `handoff_window`	Repeated closed handoff cycles inside an event window.	Your workflow legitimately revisits agents.
`semantic`	Enables the embedding-backed detector.	The agent repeats an approach using different words.

stall_patience changes StallDetector only. ProgressDetector has its own three-observation default, which this config loader does not expose. Likewise, cycle and repeated-failure thresholds require a custom detector list in Python.

Settings ending in _fatal are detector evidence hints. They do not override the policy or disable every route to STOP. For example, exact_fatal: false still allows repetition plus no progress to stop a run. Use observe-only mode when you need to guarantee that the callback will not raise an interrupt.

Enable semantic detection

Install the optional SDKs:

pip install "loopguard-runtime[semantic]"

Set semantic: true in the live section. Choose the embedding provider in your process environment: OpenAI embeddings work with the published 0.2.1 package. Gemini support is in the source checkout; its tab below includes the source installation step.

OpenAI
Gemini

export LOOPGUARD_EMBEDDING_PROVIDER=openai
export OPENAI_API_KEY=your-key

The implementation uses text-embedding-3-small by default.

git clone https://github.com/mahimathacker/loopguard.git
cd loopguard
pip install -e ".[semantic]"
export LOOPGUARD_EMBEDDING_PROVIDER=gemini
export GOOGLE_API_KEY=your-key

GEMINI_API_KEY is also accepted. The implementation uses gemini-embedding-2-preview by default. Confirm access to that model in your account.

In PowerShell, set values with $env:NAME = "value" instead of export. The library reads environment variables; it does not load .env files for you. The demo entry points load .env explicitly. Embedding calls require network access and may incur provider charges. Embeddings are cached by text within each embedder instance. The config loader does not expose an embedding-model setting; custom models are selected through Python embedder objects.

Keep config simple

The loader accepts JSON or a small YAML subset: scalar values, a section mapping, and simple lists. It does not implement full YAML features such as anchors, multiline strings, or arbitrary nesting. Use true and false for booleans. If a named live or check section is absent, that consumer falls back to top-level keys. Check flags override config values. Repeated --fail-on flags replace the configured failure set rather than extending it. All detector settings loaded from config must be positive; budgets must be positive integers. Omit a budget to leave it unset. Tune thresholds against labeled examples from your own application. Look up every supported config field or inspect saved traces while tuning.

Start here

Concepts

Use LoopGuard

Explore the demo

Test and troubleshoot

Reference

Configure LoopGuard

Start with one application config

Choose limits and sensitivity

Enable semantic detection

Keep config simple

​Start with one application config

​Choose limits and sensitivity

​Enable semantic detection

​Keep config simple

Start with one application config

Choose limits and sensitivity

Enable semantic detection

Keep config simple