Open-Source AI Debugger • Self-Hosted

Debug AI systems like you debug production software.

When normal software fails, you get stack traces, database logs, and error lines. But when an AI agent hallucinates, stalls for 10 seconds, or burns through \$50 in tokens, it’s an opaque black box.

Feenion gives you complete X-ray vision into every prompt, retrieval chunk, tool call, and token dollar β€” 100% locally on your machine.

Why Building AI Applications is Hard

Modern AI apps aren't single API calls β€” they are complex distributed systems of prompts, vector databases, and multi-step tool reasoning.

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The Black-Box Failure Problem

When an agent gives a bad answer, you don't know whether the user query was misunderstood, the vector database retrieved irrelevant docs, or the LLM failed to synthesize the answer.

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Runaway Token Costs & Latency

A single multi-turn agent loop can silently make 12 LLM calls, taking 18 seconds and costing \$0.40 per request. Without tracing, you cannot identify which step is the bottleneck.

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SaaS Data Privacy Liabilities

Sending sensitive user prompts, private enterprise knowledge base chunks, and customer conversations to external cloud observability platforms creates compliance and security risks.

The Solution: Causality Tracing

See exactly what happened at every step

Feenion reconstructs the entire execution causality tree so you can inspect inputs, outputs, tokens, latency, and costs for each component.

customer_support_pipeline tr_8fa9102c
Total Latency: 1,240ms Tokens: 842 tok Cost: $0.0034
agent handle_support_request
1,240ms
retrieval kb_vector_search (top_k=5)
298ms
tool fetch_user_account_status
186ms
llm gpt-4o synthesis
682ms
Critical Path: gpt-4o synthesis (55% total time)
Retrieved 5 chunks • 0 errors • Status 200 OK

Up and running in two simple steps

No heavy cloud infrastructure. Feenion runs as a single lightweight container and a Python library.

STEP 1: Start Feenion Server Docker

Spins up the telemetry ingestion server and React UI with embedded SQLite WAL storage on localhost:8000.

docker compose up -d
STEP 2: Install Python SDK pip

Install the zero-overhead client into your Python AI backend or agent framework.

pip install feenion
from openai import OpenAI
from feenion.integrations.openai import instrument_openai

client = OpenAI()
instrument_openai(client)

# Automatically captures tokens, latency, cost, and trace context:
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Explain Raft Consensus Algorithm."}]
)

Developer tools built for production scale

Everything needed to inspect, benchmark, and debug AI workloads.

01 / WATERFALL

Flamegraph Timelines

Instantly identify slow vector lookups and model latencies along the critical path.

02 / MIND MAP

D3 Execution DAG

Visualize complex parent-child causality graphs across agents, tools, and retrievers.

03 / COST REGISTRY

Real-Time Financials

Dynamic pricing registry calculates exact token expenditures per model and workspace.

04 / ZERO-LOCKIN

Apache 2.0 Open Source

Run forever on your own hardware without per-seat pricing or cloud vendor lock-in.