Backends, Models, and MCP

Jean is not locked to a single agent backend.

You can work with Claude CLI, Codex CLI, and OpenCode, then choose how much of that configuration is global, project-level, or session-specific.

Backends

Jean supports four backends:

• Claude CLI
• Codex CLI
• OpenCode
• Cursor Agent

You can set a global default backend and override it per project or per session.

Each backend has different capabilities. Cursor Agent, for example, only supports plan and yolo execution modes.

Models and reasoning

Model selection is session-aware.

Depending on the backend, Jean can also store and apply:

• thinking level (Claude, Codex, OpenCode)
• reasoning effort (Claude Opus adaptive)
• execution mode

That lets you keep a lighter model for quick work and a heavier one for review, investigation, or tricky implementation.

Thinking levels

For Claude CLI, Jean exposes four levels with increasing token budgets:

• Off — thinking disabled
• Think — 4K token budget
• Megathink — 10K token budget
• Ultrathink — 32K token budget (default)

Higher levels let the model reason more before answering, at the cost of more tokens and latency. Off is appropriate for short generation tasks where reasoning is not useful.

Effort levels (Opus adaptive thinking)

Latest Claude Opus models on CLI 2.1.32+ replace the thinking-level dial with an adaptive effort dial:

• Low — minimal thinking, skipped for simple tasks
• Medium — moderate thinking
• High — deep reasoning (default), almost always thinks
• xHigh — extra-high effort (recommended default for coding and agentic work on Opus 4.7)
• Max — no constraints on thinking depth

Jean picks the correct control for the selected model automatically.

Adaptive thinking per mode

Jean can apply different reasoning defaults depending on the execution mode.

Plan mode often benefits from heavier thinking. Build and Yolo can run with lighter reasoning to keep the loop fast. The Magic Prompts pane is where those per-workflow overrides live.

Providers

Jean supports custom Claude CLI provider profiles.

This is useful when you want Claude CLI to use a different endpoint or routing setup while keeping the rest of the Jean workflow unchanged.

The important distinction:

• backend chooses the tool family
• model chooses the model within that backend
• provider changes how Claude CLI is routed

MCP servers

Jean discovers MCP servers from the backends you have installed.

It reads backend-specific config locations such as:

• Claude config plus .mcp.json
• Codex config plus .codex/config.toml
• OpenCode config plus opencode.json

You can enable MCP servers:

• globally
• per project
• per session

Newly discovered servers can be auto-enabled, but Jean keeps track of servers you explicitly turned off so they do not silently reappear.

Attachments and extra context

Beyond MCP, a session can include:

• file mentions
• attached text files
• attached images
• loaded GitHub context
• loaded Linear context
• saved context snapshots
• linked project context

Jean treats these as part of the session state rather than a one-off paste.

Good defaults

For most teams, a good starting setup is:

• one default backend you trust
• project-level overrides only where they are truly useful
• MCP enabled only for tools that add clear value
• heavy models for investigation, lighter models for short generation tasks

Next reads

• Start your first session
• Project linking
• Magic commands
• Magic prompts
• Preferences and customization