Rename /branch command to /fork

- RPC: branch -> fork, get_branch_messages -> get_fork_messages
- SDK: branch() -> fork(), getBranchMessages() -> getForkMessages()
- AgentSession: branch() -> fork(), getUserMessagesForBranching() -> getUserMessagesForForking()
- Extension events: session_before_branch -> session_before_fork, session_branch -> session_fork
- Settings: doubleEscapeAction 'branch' -> 'fork'

fixes #641

packages/coding-agent/examples/extensions/README.md

@@ -20,7 +20,7 @@ cp permission-gate.ts ~/.pi/agent/extensions/
 |-----------|-------------|
 | `permission-gate.ts` | Prompts for confirmation before dangerous bash commands (rm -rf, sudo, etc.) |
 | `protected-paths.ts` | Blocks writes to protected paths (.env, .git/, node_modules/) |
-| `confirm-destructive.ts` | Confirms before destructive session actions (clear, switch, branch) |
+| `confirm-destructive.ts` | Confirms before destructive session actions (clear, switch, fork) |
 | `dirty-repo-guard.ts` | Prevents session changes with uncommitted git changes |
 
 ### Custom Tools
@@ -53,7 +53,7 @@ cp permission-gate.ts ~/.pi/agent/extensions/
 
 | Extension | Description |
 |-----------|-------------|
-| `git-checkpoint.ts` | Creates git stash checkpoints at each turn for code restoration on branch |
+| `git-checkpoint.ts` | Creates git stash checkpoints at each turn for code restoration on fork |
 | `auto-commit-on-exit.ts` | Auto-commits on exit using last assistant message for commit message |
 
 ### System Prompt & Compaction
@@ -129,7 +129,7 @@ action: Type.Union([Type.Literal("list"), Type.Literal("add")])
 
 **State persistence via details:**
 ```typescript
-// Store state in tool result details for proper branching support
+// Store state in tool result details for proper forking support
 return {
   content: [{ type: "text", text: "Done" }],
   details: { todos: [...todos], nextId },  // Persisted in session

packages/coding-agent/examples/extensions/confirm-destructive.ts

@@ -43,16 +43,16 @@ export default function (pi: ExtensionAPI) {
 		}
 	});
 
-	pi.on("session_before_branch", async (event, ctx) => {
+	pi.on("session_before_fork", async (event, ctx) => {
 		if (!ctx.hasUI) return;
 
-		const choice = await ctx.ui.select(`Branch from entry ${event.entryId.slice(0, 8)}?`, [
-			"Yes, create branch",
+		const choice = await ctx.ui.select(`Fork from entry ${event.entryId.slice(0, 8)}?`, [
+			"Yes, create fork",
 			"No, stay in current session",
 		]);
 
-		if (choice !== "Yes, create branch") {
-			ctx.ui.notify("Branch cancelled", "info");
+		if (choice !== "Yes, create fork") {
+			ctx.ui.notify("Fork cancelled", "info");
 			return { cancel: true };
 		}
 	});

packages/coding-agent/examples/extensions/dirty-repo-guard.ts

@@ -50,7 +50,7 @@ export default function (pi: ExtensionAPI) {
 		return checkDirtyRepo(pi, ctx, action);
 	});
 
-	pi.on("session_before_branch", async (_event, ctx) => {
-		return checkDirtyRepo(pi, ctx, "branch");
+	pi.on("session_before_fork", async (_event, ctx) => {
+		return checkDirtyRepo(pi, ctx, "fork");
 	});
 }

packages/coding-agent/examples/extensions/git-checkpoint.ts

@@ -1,8 +1,8 @@
 /**
  * Git Checkpoint Extension
  *
- * Creates git stash checkpoints at each turn so /branch can restore code state.
- * When branching, offers to restore code to that point in history.
+ * Creates git stash checkpoints at each turn so /fork can restore code state.
+ * When forking, offers to restore code to that point in history.
  */
 
 import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
@@ -26,7 +26,7 @@ export default function (pi: ExtensionAPI) {
 		}
 	});
 
-	pi.on("session_before_branch", async (event, ctx) => {
+	pi.on("session_before_fork", async (event, ctx) => {
 		const ref = checkpoints.get(event.entryId);
 		if (!ref) return;
 

packages/coding-agent/examples/extensions/todo.ts

@@ -131,7 +131,7 @@ export default function (pi: ExtensionAPI) {
 	// Reconstruct state on session events
 	pi.on("session_start", async (_event, ctx) => reconstructState(ctx));
 	pi.on("session_switch", async (_event, ctx) => reconstructState(ctx));
-	pi.on("session_branch", async (_event, ctx) => reconstructState(ctx));
+	pi.on("session_fork", async (_event, ctx) => reconstructState(ctx));
 	pi.on("session_tree", async (_event, ctx) => reconstructState(ctx));
 
 	// Register the todo tool for the LLM

packages/coding-agent/examples/extensions/tools.ts

@@ -138,8 +138,8 @@ export default function toolsExtension(pi: ExtensionAPI) {
 		restoreFromBranch(ctx);
 	});
 
-	// Restore state after branching
-	pi.on("session_branch", async (_event, ctx) => {
+	// Restore state after forking
+	pi.on("session_fork", async (_event, ctx) => {
 		restoreFromBranch(ctx);
 	});
 }