> ## Documentation Index > Fetch the complete documentation index at: https://docs.tyba.dev/llms.txt > Use this file to discover all available pages before exploring further. # Claude Code and Codex > The two agents TYBA starts, why they don't come in the box, and what the session shows while they work. TYBA starts **two** agents: | Agent | Binary | | ----------- | -------- | | Claude Code | `claude` | | Codex | `codex` | **Neither one is bundled.** TYBA does not embed, download or install an agent. It looks for the binary on your `PATH` and uses whatever it finds. Installing and paying for each of them is on you. Without either, TYBA is still a full terminal — what you can't do is **create an agent session**. The `PATH` it consults is your **login shell's**, not the process's. TYBA runs `$SHELL -lic` once to find out where things are, and caches the result. That is why an agent installed through `nvm`, `asdf` or Homebrew is found even when the app is opened from a GUI launcher (the Dock, on macOS), which inherits a minimal `PATH`. ## Creating an agent session | Action | macOS | Windows / Linux | | -------------------- | ----- | ------------------ | | New session | `⌘N` | `Ctrl+Shift+N` | | New worktree session | `⌘⇧T` | `Ctrl+Alt+Shift+T` | Both open the same dialog. It asks **where** the session works first: default folder, last folder, choose a folder, your home, or an SSH host. The agent choice comes after — and it **only appears when the session is isolated in a worktree**. That is where the two shortcuts differ: * `⌘⇧T` starts with **"Isolate in a git worktree"** already on. * `⌘N` respects the **"Isolate new sessions by default"** preference (Settings → Preferences, **off** by default). With the preference on, both shortcuts do the same thing. **An agent session is always a worktree session.** This is not accidental coupling: worktree, jail, env by allowlist and inbox are born together, in the same step. The whole path is in [First session](/en/first-session). Running `claude` by typing its name into a shell is a different thing — and what you lose is described in [Agent over SSH](/en/ssh/agent-over-ssh). The **"Default folder for new sessions"** preference (Settings → General) puts a folder as the **first option** in the list, marked with the `default folder` label. Empty = no default. ### When the binary isn't there **Only Codex is checked up front.** The dialog tests whether `codex` exists and, if it doesn't, disables its button with the reason: *"`codex` binary not found in PATH — install the Codex CLI"*. The **Claude Code button is never disabled.** Without `claude` installed, you pick it, submit, and only then get the error from the core: `` `claude` binary not found in PATH ``. It shows up in the dialog itself — the session doesn't start, nothing breaks, but you find out late. ### The repository's default agent A repository can pre-select the agent with `agent.default` in `.tyba/config.toml` — and that **only applies after you approve that file**. The rules (and why consent is per hash) are in [Repository configuration](/en/reference/repo-config). ## What the session reports | Status | Shows as | What it is | | -------------------------- | ---------------------- | ----------------------------------------------------------------- | | `Running` | **in progress** (blue) | working | | `AwaitingInput` · approval | **blocked** (amber) | stopped at a gate — [the inbox](/en/security/risk-classification) | | `AwaitingInput` · answer | **awaiting** (amber) | wants an answer from you | | `Idle` | **finished** (green) | the turn is over | | `Failed` | **failed** (red) | the session broke | | `Exited` | — | it's done | Two things worth knowing: **`Exited` draws nothing.** A session that ended normally gets no dot and no label — silence is the correct state for something that is over. **`Idle` only shows when it wants attention.** Once you've seen the result, the green disappears. The status shows on the **sidebar entry** and on the **hover card** — not on the tab. When a workspace has several sessions, the sidebar shows the most urgent one: failed > blocked/awaiting > finished > in progress. ## The review agent In **Settings → Code**, the **"Review agent"** field decides who receives the comments you write on a diff **when there is no live session in that worktree**. If there is a session, the prompt goes to it. With no session, TYBA opens one, starts the chosen agent and pastes the prompt. | Option | What it does | | --------------- | ----------------------------------- | | Claude Code | default | | Codex | requires `codex` on the `PATH` | | Custom command… | opens the **"Agent command"** field | **"Custom command" does not run a command.** The field accepts a line (`claude --model opus`), but TYBA reads **only the binary name** and throws the arguments away: `codex` starts Codex, **anything else starts Claude Code**. So `claude --model opus` starts a plain Claude Code, without `--model opus`. And `aider` also starts Claude Code, silently. The field's placeholder suggests otherwise — it is wrong, and the behavior above is the real one. The limitation is deliberate. An agent session has to go through the core's runner: it is what loads the hooks, the jail and the environment allowlist. An arbitrary command line would start a process **with no approval gate** — exactly what TYBA exists to prevent. ## See also Where the approval gate comes from. The long-prompt box. `agent.default` and the environment allowlist. What you lose on the other side of the pipe.