MiMo Code Integration

Séance integrates with MiMo Code through a TypeScript plugin that auto-installs to ~/.config/mimocode/plugins/. MiMo Code is a fork of OpenCode with additional subagent orchestration features.

How It Works

1. Plugin auto-installs on Séance startup (if ~/.config/mimocode exists)
2. Plugin hooks into MiMo Code's event system, forwarding lifecycle events to Séance
3. Wrapper script intercepts mimo launches, tracks PID, and fires session-end on exit

Events Handled

MiMo Code Event	Séance Hook	What It Shows
session.created	session-start	Running
session.status (busy)	prompt-submit	Running
session.status (idle)	stop	Idle
tool.execute.before	pre-tool-use	Running
tool.execute.after	post-tool-use	Running
permission.asked	notification	Needs input
session.idle	stop	Idle
session.error	session-end	(cleared)
actor.registered	prompt-submit	Running
actor.status (idle)	prompt-submit	Running

Features

• Per-surface status — each terminal pane tracks its own agent status independently
• Permission detection — shows "Waiting for permission" when MiMo Code asks to run a command
• Desktop notifications — notifies on completion and permission requests
• Subagent tracking — MiMo Code can run multiple concurrent sessions; the plugin detects subagents via tool.execute.before session ID mismatches and tracks them separately
• Activity indicators — the sidebar icon changes based on subagent activity:

Subtasks Active	Background Active	Icon
No	No	Normal
Yes	No	system-run-symbolic
No	Yes	media-playback-start-symbolic
Yes	Yes	system-run-symbolic (subtasks take precedence)

Configuration

Toggle integration on or off in config.toml:

mimocode-hooks = true

Limitations

• No session directory — MiMo Code manages sessions entirely through plugin in-memory state (unlike OpenCode/Kilo which expose session directories via environment variables)

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For Contributors

Integration Approach

MiMo Code uses a TypeScript plugin (plugins/seance-mimocode/index.ts) auto-installed to ~/.config/mimocode/plugins/. MiMo Code is a fork of OpenCode with additional subagent orchestration extensions, so the plugin shares the same base architecture but adds dedicated subagent lifecycle handling.

A wrapper script (resources/bin/mimo) intercepts launches for PID tracking and session-end on exit.

Version: @seance-version 37 (higher than OpenCode/Kilo due to subagent extensions)

Event Mapping

MiMo Code Event	Seance Hook	UI Status
session.created	session-start	Running
session.status (busy)	prompt-submit	Running
session.status (idle)	(handled by session.idle)	—
session.idle	stop	Idle
session.error	session-end	(cleared)
session.updated	session-start	Running
tool.execute.before	pre-tool-use	Running
tool.execute.after	post-tool-use	Running
permission.asked	notification	Needs input
permission.replied	(no-op)	—
actor.registered	prompt-submit	Running
actor.status (idle)	prompt-submit	Running

Unhandled events: Same as OpenCode (session.deleted, message events, file events, LSP events, etc.).

Key Implementation Details

• Status mode: Per-surface. Status key prefix mimocode, mode surface.
• clear_status_on_end is true.
• has_notification_hook is true.
• Auto-install target: ~/.config/mimocode/plugins/seance-mimocode.ts
• Disabled check: SEANCE_MIMOCODE_HOOKS_DISABLED=1.

Subagent Tracking

MiMo Code is the only agent with dedicated subagent lifecycle events:

• actor.registered: When mode === "subagent" and the agent is not "checkpoint-writer" or "compaction", adds the actor to childSessions, increments subagentCount, and fires updateCounts() + prompt-submit.
• actor.status (idle): When the actorID is in childSessions, removes it and decrements the count, firing updateCounts() + prompt-submit.

This is more reliable than the session ID mismatch heuristic used by OpenCode/Kilo.

Icon State Machine

The sidebar icon changes based on subagent/background activity:

State	Icon
No subtasks, no background	Normal icon
Subtasks active	system-run-symbolic
Background active	media-playback-start-symbolic
Both active	system-run-symbolic (subtasks take precedence)

Key Differences from OpenCode

• No completedSessions set. MiMo Code uses dedicated actor.registered/actor.status events instead of session ID mismatch heuristics.
• Session ID extraction. Uses event.properties?.sessionID directly (no fallback to event.properties?.info?.id).
• Session status mapping. Maps both busy and idle session.status events (idle handled by session.idle).
• Multiple concurrent sessions. MiMo Code can fire events from multiple concurrent sessions (foreground + background indexing), tracked via currentSessionId plus a childSessions map.

Subagent Update Command

The plugin sends a subagent-update command with workspace_id, subagent_count, and background_count whenever subagent counts change. This drives the icon state machine in the sidebar.

Upstream Framework Events

Source: github.com/XiaomiMiMo/MiMo-Code

MiMo Code is a fork of OpenCode, so it inherits all OpenCode events plus adds its own extensions for subagent management:

Inherited from OpenCode

All OpenCode/Kilo Code events (see OpenCode Integration).

MiMo Code Extensions

Event	Description	Séance Handles?
actor.registered	New actor/subagent registered	Yes
actor.status	Actor status changed	Yes

Note: MiMo Code adds actor lifecycle events that are not in the base OpenCode framework. These appear to be custom extensions for the subagent orchestration system.

Missing Event Coverage

Events that MiMo Code can emit but Séance does not currently handle (same as OpenCode, plus):

Event	Potential Use for Séance
session.deleted	Clear status when session is explicitly deleted
session.compacted	Show compaction indicator in status
message.updated	Track conversation progress
file.edited	Show file modification activity
lsp.client.diagnostics	Show error/warning counts in status
todo.updated	Track task completion progress

Impact: MiMo Code inherits OpenCode's events but Séance's plugin doesn't leverage the additional actor events for richer subagent status.