Open-source SDKSelf-hosted ConsoleEU AI Act Ready

The control plane for AI agents

See every trace, enforce every policy, prove every compliance. One SDK. One dashboard.

agent.py
import custos

@custos.agent(name="research-agent")
async def research(query: str) -> str:
    prompt = custos.get_prompt("research-system")
    return await llm.generate(prompt, query)

Your agents send data. The Console gives you control.

You built your agents. Now who's governing them?

Blind execution

Your agents run, but you can't see what they're doing, which tools they called, or why they failed. No visibility means no accountability.

Compliance blind spots

The EU AI Act demands risk assessments, audit trails, and human oversight for high-risk AI systems. Without policy enforcement, every agent output is a potential regulatory violation.

Cost surprises

A runaway agent loop burns through your API budget before you notice. Without budgets and alerts, costs spiral unchecked.

Prompt chaos

System prompts live in code, with no versioning, no rollback, no audit trail. Regulators require traceable AI decision-making — scattered prompts make that impossible.

Designed for the EU AI Act

Every capability in Custos maps to specific regulatory requirements. From risk management to audit trails, your agents are built for compliance from day one.

Art. 9Risk Management

Guardrails with block, warn, and log enforcement modes

Art. 12Record-keeping & Logging

Full execution tracing with searchable history

Art. 13Transparency & Traceability

Trace Explorer with input/output inspection per step

Art. 14Human Oversight

Real-time dashboard with violation alerts and controls

Art. 17Quality Management

Prompt Registry with version control and audit trail

Compliance Overview

On Track

Policies active

0

Compliance score

0%

EU AI Act articles

Art. 9Risk ManagementPass
Art. 12Record-keepingPass
Art. 13TransparencyPass
Art. 14Human OversightReview
Art. 17Quality ManagementPass

Last audit: 2 min ago

Your mission control for AI agents

A self-hosted dashboard to monitor, govern, and optimize every agent in production. Deploy with docker compose up.

Dashboard

Real-time overview of your entire AI fleet. See active agents, trace volume, cost trends, and policy violations at a glance.

  • Active agent count and status
  • Daily trace volume with trend
  • Cost trend with month-to-date total
  • Policy violations with regulatory context

Active agents

0

Traces/day

0

Monthly cost

$0

Violations

0

Cost trend (30d)

Recent violations

no-pii-outputsupport-agent2m ago
cost-thresholdresearch-agent14m ago
rate-limitdata-agent1h ago

How Custos works

Four pillars of agent governance — powered by the SDK, managed in the Console

Tracing

Full execution tracing with cost attribution per agent, per step. See every LLM call, tool invocation, and decision your agents make. Explore traces visually in the Console's Trace Explorer.

  • Automatic span creation for every LLM call
  • Cost attribution per agent and per step
  • Latency breakdown across the execution chain
  • Searchable trace history with filters
@custos.agent(name="research-agent")
async def research(query: str) -> str:
    # Every call is traced automatically
    result = await llm.generate(query)
    return result

Integrate in minutes

Add observability and guardrails to your existing agents with a few lines of code

agent.py
import custos

custos.init(project="my-project", api_key="cs_...")

@custos.agent(name="research-agent", version="1.0")
async def research_agent(query: str) -> str:
    # Fetch versioned prompt from registry
    prompt = custos.get_prompt("research-system")

    # LLM call — automatically traced with cost tracking
    result = await llm.generate(
        system=prompt,
        user=query,
        model="gpt-4o"
    )

    # Guardrails evaluate the output automatically
    # Policies block, warn, or log based on your rules
    return result

@custos.agent()

Automatic tracing of every execution

get_prompt()

Versioned prompts with instant rollback

Guardrails

Policy enforcement with zero latency

Works with what you already use

Framework-agnostic by design. One SDK for any Python-based agent system.

LangGraph
CrewAI
Google ADK
OpenAI Agents SDK
Your custom stack

Don't see your framework? Custos works with any Python-based agent system.

How Custos compares

The only platform combining tracing, active guardrails, prompt lifecycle, cost budgets, and regulatory compliance support.

Full execution tracing

Custos:
LangSmith:
Langfuse:
Arize Phoenix:

Active guardrails (block/warn/log)

Custos:
LangSmith:
Langfuse:
Arize Phoenix:

Prompt lifecycle (promote/rollback)

Custos:
LangSmith:
Langfuse:Basic
Arize Phoenix:

Cost budgets with alerts

Custos:
LangSmith:
Langfuse:
Arize Phoenix:

Governance dashboard

Custos:
LangSmith:
Langfuse:
Arize Phoenix:

Framework-agnostic

Custos:
LangSmith:
Langfuse:
Arize Phoenix:

Open-source SDK

Custos:
LangSmith:
Langfuse:
Arize Phoenix:

Self-hosted option

Custos:
LangSmith:
Langfuse:
Arize Phoenix:

Regulatory compliance support

Custos:
LangSmith:
Langfuse:
Arize Phoenix:

Last verified: 2026-03

Simple, transparent pricing

Start with the right plan. Scale as your agents grow.

Free

$0forever

For individuals and small teams getting started

  • Console dashboard (self-hosted)
  • 5,000 traces/month
  • 2 projects
  • 7-day data retention
  • Community support
  • Basic guardrails
  • Prompt registry (10 prompts)
Most popular

Pro

$49/seat/month

For teams running agents in production

  • Full Console with all views
  • 100,000 traces/month
  • Unlimited projects
  • 90-day data retention
  • Priority support
  • Advanced guardrails
  • Policy editor
  • Compliance policy templates
  • Unlimited prompts
  • Cost alerts & budgets
  • Webhook notifications

Enterprise

Custom

For organizations with advanced requirements

  • Managed cloud option
  • Unlimited traces
  • Unlimited projects
  • Custom data retention
  • Dedicated support
  • Custom dashboards
  • SSO / SAML
  • RBAC & audit logs
  • Compliance reporting & audit exports
  • Custom regulatory framework support
  • SLA guarantee
  • On-premise option
Contact

Tell us what matters most in your agent stack

Share your priorities, the capabilities you care about, and the level of support you need. We will route the request with context instead of a cold generic inbox.

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What happens next

  1. 01

    We review your stack, use case, and required capabilities.

  2. 02

    We reply with the right follow-up instead of a generic trial link.

  3. 03

    We keep the request protected with CAPTCHA and server-side validation.

Good fit signals

  • You need real trace visibility across agent workflows.
  • Guardrails, budgets, or prompt lifecycle are already pain points.
  • You want a self-hosted control plane instead of another black box.
Primary interest

Pick the area you want to solve first.

Requested capabilities Optional

Add extra capabilities only if you want to give us more context.

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