Quickstart

Get the dashboard running and watch a loop get flagged in three commands.

pip install "looplens[server]"
looplens dev      # start backend + prebuilt UI, opens http://localhost:8765
looplens demo     # run a sample looping agent that trips a warning

looplens dev opens the dashboard in your browser automatically (pass --no-open to skip). If it doesn't, open http://localhost:8765 yourself and watch the run appear live.

Instrument your own agent

The smallest possible integration with the manual SDK:

from looplens import trace, event

with trace("research-agent"):
    event("tool_call_started", tool="web_search", input={"query": "AI agents"})
    event("tool_call_completed", tool="web_search", output={"results": 5})

Or capture inputs, outputs, latency, and errors automatically:

from looplens import observe

@observe(kind="tool")
def web_search(query):
    ...

Already on a framework? You usually don't need any of this — see framework integration to capture runs with no LoopLens code in your agent.

Configuration

The SDK is configured entirely via environment variables:

LOOPLENS_ENDPOINT=http://127.0.0.1:8765   # where the dashboard listens
LOOPLENS_ENABLED=true                      # set false to make the SDK a no-op
LOOPLENS_PROJECT=default
LOOPLENS_CAPTURE_INPUTS=true
LOOPLENS_CAPTURE_OUTPUTS=true
LOOPLENS_TRACE_DIR=looplens-traces         # JSONL fallback location

Events are sent from a background thread, so your loop never blocks. If the dashboard is running, events stream to it live; if not, the SDK buffers them to a local JSONL file and never crashes your app.