feat(plugin): add vcs backend registration api

packages/plugin/src/v2/effect/context.ts

@@ -10,6 +10,7 @@ import type { SkillHooks } from "./skill.js"
 import type { Reload } from "./registration.js"
 import type { ToolDomain } from "./tool.js"
 import type { SessionDomain } from "./runtime.js"
+import type { VcsDomain } from "./vcs.js"
 
 export interface PluginContext {
   readonly options: PluginOptions
@@ -23,4 +24,5 @@ export interface PluginContext {
   readonly skill: SkillHooks & Reload
   readonly tool: ToolDomain
   readonly session: SessionDomain
+  readonly vcs: VcsDomain
 }

packages/plugin/src/v2/effect/index.ts

@@ -4,3 +4,5 @@ export type { Plugin } from "./plugin.js"
 export * as Tool from "./tool.js"
 export type { ToolDomain, ToolExecuteBeforeEvent, ToolExecuteAfterEvent } from "./tool.js"
 export type { SessionDomain } from "./runtime.js"
+export { Vcs } from "./vcs.js"
+export type { VcsDomain } from "./vcs.js"

packages/plugin/src/v2/effect/vcs.ts

@@ -0,0 +1,33 @@
+export * as Vcs from "./vcs.js"
+
+import { FileDiff } from "@opencode-ai/schema/file-diff"
+import { FileStatus, Mode } from "@opencode-ai/schema/vcs"
+import { Schema, type Effect, type Scope } from "effect"
+
+export class RegistrationError extends Schema.TaggedErrorClass<RegistrationError>()("Vcs.RegistrationError", {
+  type: Schema.String,
+  message: Schema.String,
+}) {}
+
+export interface AdapterScope {
+  readonly directory: string
+  readonly worktree: string
+  readonly store: string
+}
+
+export interface Adapter {
+  readonly status: () => Effect.Effect<readonly FileStatus[]>
+  readonly diff: (
+    mode: Mode,
+    options?: { readonly context?: number },
+  ) => Effect.Effect<readonly FileDiff.Info[]>
+}
+
+export interface Backend {
+  readonly type: string
+  readonly make: (scope: AdapterScope) => Adapter
+}
+
+export interface VcsDomain {
+  readonly register: (backend: Backend) => Effect.Effect<void, RegistrationError, Scope.Scope>
+}