diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index 26ca6bd5..a7dd07c5 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -15,6 +15,7 @@
 
 ### Fixed
 
+- Fixed `AgentSession` system-prompt option initialization to avoid constructing an invalid empty `BuildSystemPromptOptions`, so `npm run check` passes after `cwd` became mandatory.
 - Fixed shell-path resolution to stop consulting ambient `process.cwd()` state during bash execution, so session/project-specific `shellPath` settings now follow the active coding-agent session cwd instead of the launcher cwd ([#3452](https://github.com/badlogic/pi-mono/issues/3452))
 - Fixed `ctx.ui.setWorkingIndicator()` custom frames to render verbatim instead of forcing the theme accent color, so extensions now own working-indicator coloring when they customize it ([#3467](https://github.com/badlogic/pi-mono/issues/3467))
 - Fixed `pi update` reinstalling npm packages that are already at the latest published version by checking the installed package version before running `npm install <pkg>@latest` ([#3000](https://github.com/badlogic/pi-mono/issues/3000))
diff --git a/packages/coding-agent/src/core/agent-session.ts b/packages/coding-agent/src/core/agent-session.ts
index 77dacd5b..f90a4c8d 100644
--- a/packages/coding-agent/src/core/agent-session.ts
+++ b/packages/coding-agent/src/core/agent-session.ts
@@ -301,7 +301,7 @@ export class AgentSession {
 
 	// Base system prompt (without extension appends) - used to apply fresh appends each turn
 	private _baseSystemPrompt = "";
-	private _baseSystemPromptOptions: BuildSystemPromptOptions = {};
+	private _baseSystemPromptOptions!: BuildSystemPromptOptions;
 
 	constructor(config: AgentSessionConfig) {
 		this.agent = config.agent;