fix(coding-agent): restore /import error flow and document throws

packages/coding-agent/CHANGELOG.md

@@ -7,6 +7,7 @@
 - Fixed missing root exports for `RpcClient` and RPC protocol types from `@mariozechner/pi-coding-agent`, so ESM consumers can import them from the main package entrypoint ([#3275](https://github.com/badlogic/pi-mono/issues/3275))
 - Fixed Bun binary asset path resolution to honor `PI_PACKAGE_DIR` for built-in themes, HTML export templates, and interactive bundled assets ([#3074](https://github.com/badlogic/pi-mono/issues/3074))
 - Fixed user-message turn spacing in interactive mode by restoring an inter-message spacer before user turns (except the first user message), preventing assistant and user blocks from rendering flush together.
+- Fixed interactive `/import` handling to route missing JSONL files through the non-fatal `SessionImportFileNotFoundError` path, and documented the `importFromJsonl()` exceptions (`SessionImportFileNotFoundError`, `MissingSessionCwdError`).
 
 ## [0.67.6] - 2026-04-16
 

packages/coding-agent/src/core/agent-session-runtime.ts

@@ -33,6 +33,9 @@ export type CreateAgentSessionRuntimeFactory = (options: {
 	sessionStartEvent?: SessionStartEvent;
 }) => Promise<CreateAgentSessionRuntimeResult>;
 
+/**
+ * Thrown when /import references a JSONL file path that does not exist.
+ */
 export class SessionImportFileNotFoundError extends Error {
 	readonly filePath: string;
 
@@ -258,6 +261,13 @@ export class AgentSessionRuntime {
 		return { cancelled: false, selectedText };
 	}
 
+	/**
+	 * Import a session JSONL file and switch runtime state to the imported session.
+	 *
+	 * @returns `{ cancelled: true }` when cancelled by `session_before_switch`, otherwise `{ cancelled: false }`.
+	 * @throws {SessionImportFileNotFoundError} When the input path does not exist.
+	 * @throws {MissingSessionCwdError} When the imported session cwd cannot be resolved and no override is provided.
+	 */
 	async importFromJsonl(inputPath: string, cwdOverride?: string): Promise<{ cancelled: boolean }> {
 		const resolvedPath = resolve(inputPath);
 		if (!existsSync(resolvedPath)) {

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -47,7 +47,7 @@ import {
 	VERSION,
 } from "../../config.js";
 import { type AgentSession, type AgentSessionEvent, parseSkillBlock } from "../../core/agent-session.js";
-import type { AgentSessionRuntime } from "../../core/agent-session-runtime.js";
+import { type AgentSessionRuntime, SessionImportFileNotFoundError } from "../../core/agent-session-runtime.js";
 import type {
 	ExtensionContext,
 	ExtensionRunner,
@@ -4417,20 +4417,6 @@ export class InteractiveMode {
 			return;
 		}
 
-		const handleImportResult = async (result: "ok" | "cancelled" | "not_found"): Promise<void> => {
-			if (result === "cancelled") {
-				this.showStatus("Import cancelled");
-				return;
-			}
-			if (result === "not_found") {
-				this.showError(`Failed to import session: File not found: ${path.resolve(inputPath)}`);
-				return;
-			}
-			await this.handleRuntimeSessionChange();
-			this.renderCurrentSessionState();
-			this.showStatus(`Session imported from: ${inputPath}`);
-		};
-
 		try {
 			if (this.loadingAnimation) {
 				this.loadingAnimation.stop();
@@ -4438,7 +4424,13 @@ export class InteractiveMode {
 			}
 			this.statusContainer.clear();
 			const result = await this.runtimeHost.importFromJsonl(inputPath);
-			await handleImportResult(result);
+			if (result.cancelled) {
+				this.showStatus("Import cancelled");
+				return;
+			}
+			await this.handleRuntimeSessionChange();
+			this.renderCurrentSessionState();
+			this.showStatus(`Session imported from: ${inputPath}`);
 		} catch (error: unknown) {
 			if (error instanceof MissingSessionCwdError) {
 				const selectedCwd = await this.promptForMissingSessionCwd(error);
@@ -4447,7 +4439,17 @@ export class InteractiveMode {
 					return;
 				}
 				const result = await this.runtimeHost.importFromJsonl(inputPath, selectedCwd);
-				await handleImportResult(result);
+				if (result.cancelled) {
+					this.showStatus("Import cancelled");
+					return;
+				}
+				await this.handleRuntimeSessionChange();
+				this.renderCurrentSessionState();
+				this.showStatus(`Session imported from: ${inputPath}`);
+				return;
+			}
+			if (error instanceof SessionImportFileNotFoundError) {
+				this.showError(`Failed to import session: ${error.message}`);
 				return;
 			}
 			await this.handleFatalRuntimeError("Failed to import session", error);