Merge PR #492: Add blockImages setting

- Setting controls filtering at convertToLlm layer
- Images are always stored in session, filtered dynamically based on current setting
- Toggle mid-session works: LLM sees/doesn't see images already in session
- Fixed SettingsManager.save() to handle inMemory mode for all setters

Closes #492

packages/coding-agent/src/core/sdk.ts

@@ -20,8 +20,8 @@
  * ```
  */
 
-import { Agent, type AgentTool, type ThinkingLevel } from "@mariozechner/pi-agent-core";
-import type { Model } from "@mariozechner/pi-ai";
+import { Agent, type AgentMessage, type AgentTool, type ThinkingLevel } from "@mariozechner/pi-agent-core";
+import type { Message, Model } from "@mariozechner/pi-ai";
 import { join } from "path";
 import { getAgentDir } from "../config.js";
 import { AgentSession } from "./agent-session.js";
@@ -300,6 +300,7 @@ export function loadSettings(cwd?: string, agentDir?: string): Settings {
 		extensions: manager.getExtensionPaths(),
 		skills: manager.getSkillsSettings(),
 		terminal: { showImages: manager.getShowImages() },
+		images: { autoResize: manager.getImageAutoResize(), blockImages: manager.getBlockImages() },
 	};
 }
 
@@ -605,6 +606,43 @@ export async function createAgentSession(options: CreateAgentSessionOptions = {}
 	const promptTemplates = options.promptTemplates ?? discoverPromptTemplates(cwd, agentDir);
 	time("discoverPromptTemplates");
 
+	// Create convertToLlm wrapper that filters images if blockImages is enabled (defense-in-depth)
+	const convertToLlmWithBlockImages = (messages: AgentMessage[]): Message[] => {
+		const converted = convertToLlm(messages);
+		// Check setting dynamically so mid-session changes take effect
+		if (!settingsManager.getBlockImages()) {
+			return converted;
+		}
+		// Filter out ImageContent from all messages, replacing with text placeholder
+		return converted.map((msg) => {
+			if (msg.role === "user" || msg.role === "toolResult") {
+				const content = msg.content;
+				if (Array.isArray(content)) {
+					const hasImages = content.some((c) => c.type === "image");
+					if (hasImages) {
+						const filteredContent = content
+							.map((c) =>
+								c.type === "image" ? { type: "text" as const, text: "Image reading is disabled." } : c,
+							)
+							.filter(
+								(c, i, arr) =>
+									// Dedupe consecutive "Image reading is disabled." texts
+									!(
+										c.type === "text" &&
+										c.text === "Image reading is disabled." &&
+										i > 0 &&
+										arr[i - 1].type === "text" &&
+										(arr[i - 1] as { type: "text"; text: string }).text === "Image reading is disabled."
+									),
+							);
+						return { ...msg, content: filteredContent };
+					}
+				}
+			}
+			return msg;
+		});
+	};
+
 	agent = new Agent({
 		initialState: {
 			systemPrompt,
@@ -612,7 +650,7 @@ export async function createAgentSession(options: CreateAgentSessionOptions = {}
 			thinkingLevel,
 			tools: activeToolsArray,
 		},
-		convertToLlm,
+		convertToLlm: convertToLlmWithBlockImages,
 		sessionId: sessionManager.getSessionId(),
 		transformContext: extensionRunner
 			? async (messages) => {

packages/coding-agent/src/core/settings-manager.ts

@@ -36,6 +36,7 @@ export interface TerminalSettings {
 
 export interface ImageSettings {
 	autoResize?: boolean; // default: true (resize images to 2000x2000 max for better model compatibility)
+	blockImages?: boolean; // default: false - when true, prevents all images from being sent to LLM providers
 }
 
 export interface Settings {
@@ -170,23 +171,23 @@ export class SettingsManager {
 	}
 
 	private save(): void {
-		if (!this.persist || !this.settingsPath) return;
+		if (this.persist && this.settingsPath) {
+			try {
+				const dir = dirname(this.settingsPath);
+				if (!existsSync(dir)) {
+					mkdirSync(dir, { recursive: true });
+				}
 
-		try {
-			const dir = dirname(this.settingsPath);
-			if (!existsSync(dir)) {
-				mkdirSync(dir, { recursive: true });
+				// Save only global settings (project settings are read-only)
+				writeFileSync(this.settingsPath, JSON.stringify(this.globalSettings, null, 2), "utf-8");
+			} catch (error) {
+				console.error(`Warning: Could not save settings file: ${error}`);
 			}
-
-			// Save only global settings (project settings are read-only)
-			writeFileSync(this.settingsPath, JSON.stringify(this.globalSettings, null, 2), "utf-8");
-
-			// Re-merge project settings into active settings
-			const projectSettings = this.loadProjectSettings();
-			this.settings = deepMergeSettings(this.globalSettings, projectSettings);
-		} catch (error) {
-			console.error(`Warning: Could not save settings file: ${error}`);
 		}
+
+		// Always re-merge to update active settings (needed for both file and inMemory modes)
+		const projectSettings = this.loadProjectSettings();
+		this.settings = deepMergeSettings(this.globalSettings, projectSettings);
 	}
 
 	getLastChangelogVersion(): string | undefined {
@@ -398,6 +399,18 @@ export class SettingsManager {
 		this.save();
 	}
 
+	getBlockImages(): boolean {
+		return this.settings.images?.blockImages ?? false;
+	}
+
+	setBlockImages(blocked: boolean): void {
+		if (!this.globalSettings.images) {
+			this.globalSettings.images = {};
+		}
+		this.globalSettings.images.blockImages = blocked;
+		this.save();
+	}
+
 	getEnabledModels(): string[] | undefined {
 		return this.settings.enabledModels;
 	}