src/index.ts delivers the plugin assembly layer: it loads configuration, resolves agent definitions, precomputes runtime model fallback chains, wires multiplexer/session orchestration, registers tools/MCPs/hooks, and returns the OpenCode plugin registration object.
config/, agents/, tools/, multiplexer/, hooks/, and utils/ contain the reusable building blocks (loader/schema/constants, agent factories/permission helpers, tool factories, session mirroring managers, hook implementations, and runtime utilities) that power that entry point.
hooks/task-session-manager is now part of the core plugin flow to support resumable child task sessions with concise aliases and reminder injection for orchestrator calls.
Agent creation follows explicit factories (agents/index.ts, per-agent creators under agents/) with override/permission helpers (config/schema.ts, cli/skills.ts, config/agent-mcps.ts) so defaults live in config/constants.ts, prompts can be swapped via config/loader.ts, and variant labels propagate through utils/agent-variant.ts.
Session orchestration combines SubagentDepthTracker, MultiplexerSessionManager, CouncilManager, and ForegroundFallbackManager; these coordinate subagent depth limits, pane lifecycle, council session creation, and foreground model failover.
Hook composition is centralized in src/index.ts: lifecycle event handlers and tool transform handlers fan out to specialized hooks, then some hooks post-process system messages in-place for provider compatibility.
Supplemental tools bundle AST-grep search/replace, council orchestration, and web fetching behind the OpenCode tool interface and are mounted in index.ts alongside hooks and MCP helpers.
Flow
Startup:
loadPluginConfig builds effective config from user/project presets.
createAgents + getAgentConfigs construct final agent registry and resolved prompts.
Runtime model chains are built from configured arrays plus fallback chains.
SubagentDepthTracker, MultiplexerSessionManager, CouncilManager, ForegroundFallbackManager, and hook factories are initialized before registration.
Plugin registration: index.ts merges/overlays agent configs into OpenCode's config, registers tools (council, webfetch, ast_grep_*, todo tools), MCPs (createBuiltinMcps), and all hook handlers (event, tool.execute.before/after, experimental.chat.system/messages.transform, command.execute.before, etc.).
Runtime event flow (event): updates depth tree, multiplexer pane state, auto-update checks, interview/preset state, and task-session cleanup for deleted sessions.
experimental.chat.system.transform pipeline:
injects orchestrator/system-level reminders when required,
applies task/session prompt enrichment from task-session-manager,
collapses all system entries into one message via collapseSystemInPlace for providers that reject multi-message system arrays.
tool.execute.before/after (task): records pending task calls, resolves short aliases to canonical IDs, parses outputs for new task IDs, and updates/removes remembered sessions.
CLI flow: cli/install.ts parses flags, optionally prompts, checks OpenCode installation, updates config via cli/config-io.ts and cli/paths.ts, disables default agents, writes lite config, and installs skills (cli/skills.ts, cli/custom-skills.ts).
Integration
Connects directly to @opencode-ai/plugin: returns the plugin object, mutates runtime agent configuration, handles event hooks, and routes RPC via ctx.client/ctx.client.session.
Integrates with host multiplexer backends through src/multiplexer, and with session lifecycle constraints through SubagentDepthTracker.
Hooks/subtask integration points now include:
createTaskSessionManagerHook for resumable Task sessions,
createTodoContinuationHook, createPhaseReminderHook, createFilterAvailableSkillsHook, and createPostFileToolNudgeHook for chat/tool behavior,
