> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mcpjam.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Claude Code host
> Run the real Claude Code agent inside your project's Computer — observe its native tools, MCP client, and execution behavior directly
Selecting **Claude Code** as a host runs the real Claude Code agent inside your project's Computer (a cloud Linux sandbox) instead of MCPJam's emulated chat loop. You are observing the actual runtime — its native tools, its own MCP client, its real execution behavior — not a simulation of it.
The Claude Code host is available to organizations where the feature has been
enabled. Contact your account team if you don't see it in the host template
catalog.
## What happens when you run a turn
1. **Pre-flight check.** Before the stream opens, MCPJam verifies that the host can run: the model is an MCPJam-provided Anthropic model, the Computer data plane is configured, and the host settings are ones the runtime can honor. Any failure returns a clear error before the turn starts — a turn never silently falls back to the emulated engine.
2. **Computer wake.** The host's project Computer is reserved or woken (provisioned on first use). The Claude Code host **requires** a Computer — there is no local fallback.
3. **Credential delivery.** MCPJam installs a short-lived model credential into the sandbox's egress layer outside the VM. Neither the sandbox nor your browser ever holds a real model key. The agent runs pointed at MCPJam's model proxy, which verifies the credential and meters every generation. There is no raw-key fallback.
4. **MCP delivery.** Selected MCP servers are written into the session's MCP config, each pointed at MCPJam's per-server proxy tunnel — no upstream credentials enter the sandbox.
5. **The turn runs.** Claude Code's own agent loop executes; native tools (Bash, Read, Write, and others) run inside the sandbox; file changes land on the Computer's disk; the transcript and trace persist like any other chat.
## Host settings
| Setting | Behavior |
| --------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Model | Honored — must be an MCPJam-provided Anthropic model. Bring-your-own-key models are not supported and fail closed. |
| System prompt | Honored — passed to the runtime. |
| Require tool approval | The toggle is disabled for Claude Code hosts. A host that already had approval enabled before switching to Claude Code will have approval honored for native tools: side-effecting built-ins (Bash, Write, etc.) pause the turn for your decision; read-only tools run freely. Approval cannot be combined with selected MCP servers — that combination is rejected at pre-flight. |
| Selected MCP servers | Honored — delivered via the session's MCP config through MCPJam's proxy. |
| Skills | Honored — runtime skills are materialized into the sandbox. |
| Temperature and other sampling controls | Not honored — the Claude Code runtime owns its own sampling. These controls are grayed out in the UI. |
| Progressive tool disclosure | Not applied — the real runtime owns tool discovery. |
Host-page tool-level toggles (such as tool visibility) are not re-enforced
for Claude Code runs. Controls the runtime cannot honor are disabled in the UI
rather than silently ignored.
## Requirements
* A project **Computer** (the E2B data plane must be configured for your deployment).
* An **MCPJam-provided Anthropic model** selected on the host.
* A **signed-in project member** — guest sessions cannot run the Claude Code host.
No credential configuration is needed. Broker delivery is on by default and the model proxy is always-on.
## Billing
* **Computer time** — the Claude Code runtime keeps the Computer awake, so it meters into your org's monthly computer-time allowance exactly like terminal use.
* **Model tokens** — every generation is priced and settled by the model proxy against your org, the same accounting as regular chat. Spend caps and empty-wallet rejections apply before the stream starts.
## Failure modes
None of these fall back to the emulated engine — a turn that says it ran the real runtime did. All fail closed; a failed start spends nothing.
| Condition | What you see |
| --------------------------------------------------- | ----------------------------------------------------------------------------- |
| Enterprise-managed authorization policy on the host | Pre-flight error — the combination is rejected rather than silently bypassed. |
| Require tool approval + selected MCP servers | Pre-flight error — turn approval off or remove the MCP servers. |
| Computer data plane not configured | Pre-flight error naming the data plane requirement. |
| Model not MCPJam-provided or not runnable | Pre-flight error asking you to pick an eligible model. |
| Computer at daily start cap | Start-limit dialog with upgrade option. |
| Org out of compute allowance and credits | Computer pauses with a billing notice. |
| Org spending limit reached | Clean rejection before any model call. |
| Sandbox dies mid-run | Turn errors; the next turn starts a fresh session. |
## Related
* [Computer](/inspector/computer) — Manage your project's Computer, sandbox images, and lifecycle.
* [Playground](/inspector/playground) — The workspace where you select hosts and run turns.