mirri acp Subcommand

mirri acp switches Mirri Code to ACP (Agent Client Protocol) mode: it communicates with an ACP client (such as Zed, JetBrains AI Chat, etc.) via JSON-RPC over stdin/stdout, letting the IDE directly drive mirri's sessions, prompts, and tool calls.

mirri acp

Once started, the command prints no banner and immediately waits for the ACP client to send an initialize request on stdin. Logs are written to stderr (as well as the diagnostic log under ~/.mirri-code/logs/), so the ACP channel itself stays clean.

Who calls this?

You typically do not need to run mirri acp manually — this command is the subprocess entry point for IDEs. For IDE-side configuration, see Using in IDEs.

Capability Matrix

The table below lists the capabilities declared by the current ACP adapter layer. The agentCapabilities field is returned in full in the initialize response, so the IDE can adjust its UI accordingly.

Capability	Value	Description
promptCapabilities.image	true	Supports ACP image content blocks (base64 + mimeType)
promptCapabilities.audio	false	Audio prompts not yet supported
promptCapabilities.embeddedContext	true	Client may send resource/resource_link embedded resource blocks; text content is injected into the prompt as <resource uri="...">...</resource>; blob resources are dropped with a warn
mcpCapabilities.http	true	Forwards HTTP MCP services configured by the IDE
mcpCapabilities.sse	true	Forwards legacy SSE MCP services configured by the IDE
loadSession	true	Supports session/load to resume an existing session, replaying history on load
sessionCapabilities.list	{}	Supports session/list to enumerate the current user's sessions

ACP Method Coverage

The spec divides methods into a stable surface and an evolving unstable surface (handlers mounted with the unstable_* prefix in @agentclientprotocol/sdk@0.23.0). The two have entirely different stability guarantees — the stable surface covers methods every production ACP client uses, while the unstable surface covers experimental extensions (inline-edit prediction, document buffer sync, provider management, elicitation, etc.) — so they are tracked separately.

Summary: stable agent-side 10/12 (83%) + client reverse-RPC 4/9 (44%); unstable surface has only session/set_model (1/19). All methods needed for a normal agent flow (initialize → new/load/resume → prompt → cancel + file I/O + tool approval) are implemented.

Stable agent-side — IDE → agent (10 / 12)

Method	Implemented	Description
initialize	Yes	Version negotiation; returns agentInfo: { name: 'Mirri Code', version }, capability matrix, and authMethods
authenticate	Yes	Managed login is retired: no auth methods are advertised; every method_id is rejected with invalidParams (-32602)
session/new	Yes	Accepts cwd / mcpServers; returns configOptions[]
session/load	Yes	Restores a session from disk and replays history via session/update
session/resume	Yes	Lightweight sibling of session/load; skips history replay
session/prompt	Yes	Accepts text / image / resource / resource_link content blocks; streams agent_message_chunk
session/cancel	Yes	Interrupts the current turn
session/list	Yes	Enumerates sessions on disk (advertised via sessionCapabilities.list = {})
session/set_mode	Yes	Compatibility path; dispatches to the same handler as set_config_option({configId:'mode'})
session/set_config_option	Yes	Unified model / thinking / mode picker dispatcher
session/close	No
logout	No

Stable client-side reverse-RPC — agent → IDE (4 / 9)

Method	Implemented	Description
session/update	Yes	Streams agent_message_chunk / tool_call* / plan / config_option_update / available_commands_update
session/request_permission	Yes	Shared channel for tool approval and question elicitation
fs/read_text_file	Yes	Engine file reads are routed to the client (advertised via fsCapabilities)
fs/write_text_file	Yes	Engine file writes are routed to the client
terminal/create · output · release · kill · wait_for_exit	No	Terminal reverse-RPC not connected; shell commands use local execution

Unstable surface (1 / 19)

Method	Implemented	Description
session/set_model	Yes	Compatibility path; equivalent to set_config_option({configId:'model'})
Remaining 18 methods	No	Includes session lifecycle extensions, buffer sync, inline-edit prediction, provider management, etc.

All methods not listed above return methodNotFound.

MCP Forwarding

When an ACP client provides mcpServers in session/new or session/load, the adapter layer performs the following conversions:

• http → mirri's transport: 'http' configuration
• stdio → mirri's transport: 'stdio' configuration
• sse → mirri's transport: 'sse' configuration
• acp → discarded with a warn log entry

Engine selection and desktop sharing

When mirri acp starts, it automatically probes for a locally running desktop service (the backend of the Mirri Code desktop app). When one is found, the ACP host reuses it as a remote client — sessions driven from the IDE run directly inside the desktop engine, and the desktop UI sees session progress (message increments, tool call progress) live; sessions are also stored by the desktop app. When you code in the IDE and switch to the desktop app for review, both sides are looking at the same session.

If the probe fails, it silently falls back to running standalone, with behavior identical to before — no configuration needed:

• The desktop app is not running
• The desktop app is too old, or the connection fails
• The desktop app quits mid-session and reconnection fails — in-flight turns end with a connection error, and new sessions created afterwards are served by the standalone engine

Related environment variable switches:

• MIRRI_ACP_ENGINE=embedded: skip the probe and always run standalone — useful for debugging or full isolation from the desktop app
• MIRRI_ACP_REMOTE_ENGINE: explicitly point at a remote engine and connect directly (highest priority; behavior unchanged from before)

When the desktop engine is reused, there is one directory requirement: the IDE session's directory must have been opened in the desktop app before (registered as a workspace). Creating a session in an unregistered directory is rejected, with an error prompting you to open that directory in the desktop app first.

Next steps

• Using in IDEs — Zed / JetBrains configuration steps and troubleshooting
• mirri Command Reference — Complete subcommand list