CARBON · Built by testers.aiFree & Pro

Different perspectives. One harness.

Jay’s AI testing team

AI-generated testing perspectives, not human reviewers. Select a profile to explore its focus.

Choose your CARBON edition

Your agent’s plan. Your local workspace.

Existing model accessNo separate CARBON model keyLocal evidence & reports

In Claude Code, Codex, and other coding agents, default CARBON tests use your agent’s configured model access. Signed in with an eligible subscription? CARBON uses that allowance. Using API credentials? API billing applies.

Local storage ≠ local-only AI. Local runs keep files, evidence, and reports in your workspace. Your coding agent may send code, screenshots, and other context to its model provider.

Billing, privacy & MCP details

Plan limits and extra-usage charges still apply. CARBON Pro licensing and CARBON Cloud are separate. Optional direct-model checks and external integrations can have separate costs and data flows. Command-usage analytics vary by edition—review its privacy policy and settings. Local does not mean offline or air-gapped.

Check /status in Claude Code or codex login status in Codex to confirm your billing route. A configured API key can select API billing instead of subscription usage. A standalone MCP client supplies the model access and execution tools; the MCP server does not include a subscription.

Provider documentation: Claude Code billing · Codex sign-in and billing.

INSIDE YOUR AI CODING AGENT

Start Free. Go deeper with Pro.

Choose your workspace: use CARBON in Claude Code or Cowork, or get CARBON Studio Lite for Codex (free, v0.1.12). For the native visual workspace and advanced testing, choose CARBON Studio Pro. Paid binaries are delivered separately to licensed customers.

Real testing, real evidence. Choose a useful assessment today—or an ongoing quality system for your team.

CARBON Free

Find real bugs.

Free · no account required

A complete, bounded assessment inside the coding agent you already use.

  • Risk-ranked checks and stateful bug hunting
  • Persona journeys and accessibility investigations
  • Live reports, screenshot maps and confidence summaries
  • Every recorded finding and portable HTML/JSON exports
Get CARBON Free

Use it at work. No run quota or hidden findings.
Uses your agent’s existing model access; its plan limits or API charges apply.

CARBON Pro

Keep getting better.

Compare paid plans below

Continuous coverage, deeper investigations and your team in the workflow.

  • Continuous discovery and test-fix-retest loops
  • Dedicated security, privacy, performance and other specialists
  • Test generation, repair, confidence investigations and trends
  • Persistent map steering, team tools and private feedback services
Compare paid plans

See current pricing and plan details. Questions before choosing? Email jason@testers.ai.

CARBON Light is MIT open source on both Claude and Codex. The separate Codex Studio Lite package is also MIT open source. Pro is commercially licensed. CARBON Cloud is a separate service.

CARBON Test Harness plans

Choose a plan for testing inside your AI coding agent. Compare the current prices and plan details below, then continue securely with Stripe.

Your coding agent’s model access and usage limits still apply. CARBON Cloud and CARBON Private Cloud are separate offerings, not included with these harness plans.

CARBON · Let’s talk

What would better QA look like for you?

Tell us a little about your team. We’ll help you choose a useful starting point before you sign up. No account. No payment.

Your contact details and testing needs
Your role
What are you interested in?

Prefer email? jason@testers.ai. Please don’t include passwords or confidential customer data.