Claude Code (Claude Agent)

TatsuCode hosts Claude Code as a first-class CLI provider. If you have a Claude Pro, Max, Team, or Enterprise subscription, you can enable Claude Code inside TatsuCode and use its full agentic capabilities — without paying API token rates on top of your existing subscription.

You sign in to Claude Code through the Claude Code CLI itself, not through TatsuCode. TatsuCode only enables and drives the CLI once it's already authenticated — we deliberately stay out of the Anthropic login to respect Anthropic's terms of service.

This is the headline feature of the v0.9.107 release for Claude subscribers.

What You Get

• Use your subscription, not your wallet. Once the Claude Code CLI is signed in with the Anthropic account behind your Claude Pro / Max / Team / Enterprise plan, TatsuCode uses that subscription directly. No API key billing.
• Claude Code's native tools. Claude's own Read, Edit, Bash, Glob, Grep, WebSearch, WebFetch, and parallel Task runner — all available in your TatsuCode session.
• Plus TatsuCode's tools. Screenshots, DevBrowser, Office documents, image generation, Unity Editor, the rest of the tatsu_* tools — exposed to Claude Code via MCP.
• Streaming, durable file diffs, session restore. First-class chat experience, just like API-backed providers.
• Cross-Agent Relay. Every Claude Code run is archived as report.md and can hand off to other agents (or future runs) via continueFrom.

Set Up

Authentication happens in the Claude Code CLI itself, not in TatsuCode. To respect Anthropic's terms of service, TatsuCode never handles your Anthropic login — it only enables the already-authenticated CLI.

1. Sign in to Claude Code first. If you haven't already, install the claude CLI and run its own login flow (claude → /login) using the Anthropic account behind your Claude Pro / Max / Team / Enterprise plan. Claude Code stores the auth token under ~/.claude/.
2. Send one message in Claude Code directly, before using it in TatsuCode. Open a terminal, run claude, and send a single message (e.g. "hello"). This completes any first-run setup — the trust prompt, the one-time "Bypass Permissions" acknowledgement, theme selection, and the login flow — so the CLI is fully ready. TatsuCode drives Claude Code non-interactively and can't complete these one-time browser/login steps for you.
3. In TatsuCode, open /connect and select Claude Agent (Claude Code) to enable it.
4. The Claude Code models now appear in /models.

The CLI owns the auth token — TatsuCode never sees, stores, or transmits your Anthropic credentials. If the CLI isn't signed in yet, enabling Claude Agent won't connect until you complete the CLI login.

If TatsuCode says "Claude Code isn't fully set up yet": it detected that the CLI isn't authenticated or still has a first-run prompt pending. Open Claude Code on its own, send a single message to clear it, then try again in TatsuCode.

Requirements

• An active Claude Pro, Max, Team, or Enterprise subscription. (Free Claude.ai accounts cannot run Claude Code.)
• A working internet connection. Like other cloud providers, Claude Code is online-only.

Two Ways to Use It

1. As your main chat model

Pick a Claude Code model from /models and chat normally. Claude Code drives the whole turn — picking which tools to call (its own and TatsuCode's), streaming output back to you, and producing a final response.

This is the simplest path and the one most users want.

2. Delegated to from another main model

When your main chat is running on a different model (say GPT-5.5 or Gemini), you can still get Claude Code involved for a specific subtask — just ask the main model to delegate. The main model has a ClaudeAgent tool available and will call it on your behalf.

You don't write the tool call yourself. You ask in plain language:

"Use Claude Code to find every place the auth middleware decides whether to issue a session token. We're investigating CVE-2026-0001 — see /docs/incident.md."

"Delegate steps 1 through 5 to Claude Agent, get a full report back, then review its work."

"Have Claude Code continue from the previous exploration and propose a fix."

The main model picks up the request, packages it as a delegation, and runs Claude Code in the background. When Claude Code finishes, the main model receives a structured report.md and folds the findings back into your conversation. You can hand that same report.md to another agent later — that's the relay.

The same pattern applies in reverse: when Claude Code is your main chat, you can ask it to delegate to GPT, Gemini, or any other CLI provider you have connected.

What's Different from API-Key Claude

Background Shells

When Claude Code launches a long-running shell command in the background (e.g., a ping, a build watcher, a dev server), TatsuCode tracks it across turn boundaries. While the shell is alive you'll see a small terminal badge near the input field showing how many background shells are running, with a tooltip listing each one and how long it's been alive.

If a turn ends with shells still running, the badge stays visible with a quiet "reply to follow up" hint. That tells you the input is live and a reply will route back into the same Claude session — so you can ask "is the build done?" or "kill that ping" and Claude addresses the same shell handle. The badge clears automatically when Claude reports the shell has terminated.

This is built on Claude Code's own Bash(run_in_background:true) + BashOutput + KillShell tools — TatsuCode just makes them visible across the gap between turns.

Limitations

• Cannot be assigned as a Task Agent. Same reason as every other CLI provider — the Task Agent's tool whitelist doesn't apply when the CLI drives its own loop. Use the ClaudeAgent tool instead for delegated exploration. See CLI vs API/Subscription Providers for the structural reasons.
• Cannot run in parallel today. Single CLI run at a time. Parallel CLI execution is on the roadmap.
• Token / cost accounting is best-effort. Subscription auth means per-call cost isn't reported, so /usage for CLI turns shows estimates only.
• TatsuCode's auto-compact doesn't apply. Claude Code manages its own context window during a run.

Known Issues

• In-app "Update CLI" can time out on managed / enterprise Windows networks. The Update CLI button (/connect → Claude Code) runs claude update in the background, which self-downloads and replaces the CLI binary. On corporate networks the background process doesn't inherit your terminal's proxy / TLS-interception certificate settings, so the download stalls and the update eventually times out — even though the same claude update works fine in a terminal on the same machine (the terminal has that network setup). Workaround: run claude update in a terminal, then click Refresh in the modal — TatsuCode picks up the new version with no app restart. (A proper in-app fix is being investigated.)

FAQ

Do I still need an Anthropic API key?
No. If your goal is to use Claude inside TatsuCode and you have a Claude subscription, sign in to the Claude Code CLI, enable Claude Agent in TatsuCode, and you're done.

Will my Claude Pro quota apply?
Yes. The CLI uses your subscription's quota directly. Heavy use will count against your plan's limits the same way it would inside Anthropic's own clients. You can check how much of your subscription quota is left from inside TatsuCode with /usage-quota.

Can I switch back to API-backed Claude mid-conversation?
Yes — switch the active model from /models. With Cross-Agent Relay, you can also hand off the conversation context cleanly.

What about Claude Free?
Claude Code requires an active paid subscription. Free Claude.ai accounts can't run it.

TatsuCode says Claude Code "isn't fully set up yet" — what do I do?
That message means the CLI isn't authenticated yet, or a first-run prompt (folder-trust, the one-time bypass-permissions acknowledgement, theme, or login) is still blocking it. Open a terminal, run claude, and send a single message to clear it. Once Claude Code replies on its own, it's ready — switch back to TatsuCode and try again.

Next Steps

• CLI Providers Overview — how CLI providers work, Cross-Agent Relay, stdin routing
• Providers — connect, disconnect, manage
• CLI vs API/Subscription Providers — full feature matrix