Add configurable env tail append option

lib/config.ts

@@ -9,14 +9,17 @@ const CONFIG_PATH = getOpenCodePath("openhax-codex-config.json");
  * CODEX_MODE is enabled by default for better Codex CLI parity
  * Prompt caching is enabled by default to optimize token usage and reduce costs
  */
-const DEFAULT_CONFIG: PluginConfig = {
-	codexMode: true,
-	enablePromptCaching: true,
-	logging: {
-		showWarningToasts: false,
-		logWarningsToConsole: false,
-	},
-};
+function getDefaultConfig(): PluginConfig {
+	return {
+		codexMode: true,
+		enablePromptCaching: true,
+		appendEnvContext: process.env.CODEX_APPEND_ENV_CONTEXT === "1",
+		logging: {
+			showWarningToasts: false,
+			logWarningsToConsole: false,
+		},
+	};
+}
 
 let cachedPluginConfig: PluginConfig | undefined;
 
@@ -38,10 +41,11 @@ export function loadPluginConfig(options: { forceReload?: boolean } = {}): Plugi
 	}
 
 	try {
+		const defaults = getDefaultConfig();
 		const fileContent = safeReadFile(CONFIG_PATH);
 		if (!fileContent) {
 			logWarn("Plugin config file not found, using defaults", { path: CONFIG_PATH });
-			cachedPluginConfig = { ...DEFAULT_CONFIG };
+			cachedPluginConfig = { ...defaults };
 			return cachedPluginConfig;
 		}
 
@@ -50,20 +54,21 @@ export function loadPluginConfig(options: { forceReload?: boolean } = {}): Plugi
 
 		// Merge with defaults (shallow merge + nested logging merge)
 		cachedPluginConfig = {
-			...DEFAULT_CONFIG,
+			...defaults,
 			...userConfig,
 			logging: {
-				...DEFAULT_CONFIG.logging,
+				...defaults.logging,
 				...userLogging,
 			},
 		};
 		return cachedPluginConfig;
 	} catch (error) {
+		const defaults = getDefaultConfig();
 		logWarn("Failed to load plugin config", {
 			path: CONFIG_PATH,
 			error: (error as Error).message,
 		});
-		cachedPluginConfig = { ...DEFAULT_CONFIG };
+		cachedPluginConfig = { ...defaults };
 		return cachedPluginConfig;
 	}
 }

lib/request/fetch-helpers.ts

@@ -124,7 +124,7 @@ export async function transformRequestForCodex(
 	userConfig: UserConfig,
 	codexMode = true,
 	sessionManager?: SessionManager,
-	_pluginConfig?: PluginConfig,
+	pluginConfig?: PluginConfig,
 ): Promise<
 	| {
 			body: RequestBody;
@@ -160,7 +160,9 @@ export async function transformRequestForCodex(
 			codexMode,
 			{
 				preserveIds: sessionContext?.preserveIds,
+				appendEnvContext: pluginConfig?.appendEnvContext ?? process.env.CODEX_APPEND_ENV_CONTEXT === "1",
 			},
+
 			sessionContext,
 		);
 		const appliedContext =

lib/request/request-transformer.ts

@@ -25,6 +25,8 @@ export { getModelConfig, getReasoningConfig, normalizeModel } from "./model-conf
 export interface TransformRequestOptions {
 	/** Preserve IDs when prompt caching requires it. */
 	preserveIds?: boolean;
+	/** Reattach env/files context to prompt tail (defaults from config/env). */
+	appendEnvContext?: boolean;
 }
 
 export interface TransformResult {
@@ -37,6 +39,7 @@ async function transformInputForCodex(
 	codexMode: boolean,
 	preserveIds: boolean,
 	hasNormalizedTools: boolean,
+	appendEnvContext: boolean,
 	sessionContext?: SessionContext,
 ): Promise<void> {
 	if (!body.input || !Array.isArray(body.input)) {
@@ -62,8 +65,7 @@ async function transformInputForCodex(
 	}
 
 	if (codexMode) {
-		const appendEnvTail = process.env.CODEX_APPEND_ENV_CONTEXT === "1";
-		if (appendEnvTail) {
+		if (appendEnvContext) {
 			const result = await filterOpenCodeSystemPromptsWithEnv(workingInput);
 			workingInput = result?.input;
 			if (result?.envSegments?.length) {
@@ -126,8 +128,16 @@ export async function transformRequestBody(
 	logCacheKeyDecision(cacheKeyResult, isNewSession);
 
 	const hasNormalizedTools = normalizeToolsForCodexBody(body, false);
-
-	await transformInputForCodex(body, codexMode, preserveIds, hasNormalizedTools, sessionContext);
+	const appendEnvContext = options.appendEnvContext ?? process.env.CODEX_APPEND_ENV_CONTEXT === "1";
+
+	await transformInputForCodex(
+		body,
+		codexMode,
+		preserveIds,
+		hasNormalizedTools,
+		appendEnvContext,
+		sessionContext,
+	);
 
 	const reasoningConfig = getReasoningConfig(originalModel, modelConfig);
 	body.reasoning = {

lib/types.ts

@@ -17,6 +17,12 @@ export interface PluginConfig {
 	 */
 	enablePromptCaching?: boolean;
 
+	/**
+	 * Reattach stripped environment/file context to the end of the prompt
+	 * Default inherits from CODEX_APPEND_ENV_CONTEXT env var
+	 */
+	appendEnvContext?: boolean;
+
 	/**
 	 * Logging configuration that can override environment variables
 	 */

spec/append-env-context-config.md

@@ -0,0 +1,29 @@
+# Append Env Context Config
+
+## Scope
+
+- Add `appendEnvContext` to plugin config with default derived from `CODEX_APPEND_ENV_CONTEXT`.
+- Route env/file tail reattachment through config/options instead of global env in transforms.
+- Make tests explicit about env-tail behavior to avoid leaked env state.
+
+## Touched Files
+
+- lib/types.ts (PluginConfig additions)
+- lib/config.ts (default config from env, merge logic)
+- lib/request/request-transformer.ts (options-driven appendEnvContext handling)
+- lib/request/fetch-helpers.ts (propagate config to transform)
+- test/request-transformer.test.ts (explicit appendEnvContext expectations)
+- test/cache-e2e.test.ts (pass plugin config with appendEnvContext=false)
+- test/plugin-config.test.ts (cover env default + overrides, reset env)
+
+## Definition of Done
+
+- appendEnvContext configurable via config file with default from env.
+- Transform respects config-driven appendEnvContext; no hard env dependency in tests.
+- Cache/request-transformer tests pass with explicit config; plugin config tests cover new field.
+- pnpm test test/cache-e2e.test.ts test/request-transformer.test.ts test/plugin-config.test.ts succeeds.
+
+## Notes
+
+- No existing issues/PRs linked for this change.
+- Defaults recalc on load; `forceReload` picks up env changes.

test/cache-e2e.test.ts

@@ -2,7 +2,7 @@ import { describe, it, expect, vi, afterEach } from "vitest";
 import { transformRequestForCodex } from "../lib/request/fetch-helpers.js";
 import { SessionManager } from "../lib/session/session-manager.js";
 import * as openCodeCodex from "../lib/prompts/opencode-codex.js";
-import type { InputItem, RequestBody, UserConfig } from "../lib/types.js";
+import type { InputItem, PluginConfig, RequestBody, UserConfig } from "../lib/types.js";
 import * as logger from "../lib/logger.js";
 
 const CODEX_INSTRUCTIONS = "codex instructions";
@@ -30,7 +30,11 @@ function envMessage(date: string, files: string[]): InputItem {
 	};
 }
 
-async function runTransform(body: RequestBody, sessionManager: SessionManager) {
+async function runTransform(
+	body: RequestBody,
+	sessionManager: SessionManager,
+	pluginConfig: PluginConfig = { appendEnvContext: false },
+) {
 	const init: RequestInit = { body: JSON.stringify(body) };
 	const result = await transformRequestForCodex(
 		init,
@@ -39,6 +43,7 @@ async function runTransform(body: RequestBody, sessionManager: SessionManager) {
 		USER_CONFIG,
 		true,
 		sessionManager,
+		pluginConfig,
 	);
 	if (!result) throw new Error("transformRequestForCodex returned undefined");
 	return result;

test/plugin-config.test.ts

@@ -29,9 +29,13 @@ beforeEach(async () => {
 
 describe("Plugin Configuration", () => {
 	let originalEnv: string | undefined;
+	let originalAppendEnv: string | undefined;
 
 	beforeEach(() => {
 		originalEnv = process.env.CODEX_MODE;
+		originalAppendEnv = process.env.CODEX_APPEND_ENV_CONTEXT;
+		delete process.env.CODEX_MODE;
+		delete process.env.CODEX_APPEND_ENV_CONTEXT;
 		vi.clearAllMocks();
 	});
 
@@ -41,6 +45,12 @@ describe("Plugin Configuration", () => {
 		} else {
 			process.env.CODEX_MODE = originalEnv;
 		}
+
+		if (originalAppendEnv === undefined) {
+			delete process.env.CODEX_APPEND_ENV_CONTEXT;
+		} else {
+			process.env.CODEX_APPEND_ENV_CONTEXT = originalAppendEnv;
+		}
 	});
 
 	describe("loadPluginConfig", () => {
@@ -52,6 +62,7 @@ describe("Plugin Configuration", () => {
 			expect(config).toEqual({
 				codexMode: true,
 				enablePromptCaching: true,
+				appendEnvContext: false,
 				logging: { showWarningToasts: false, logWarningsToConsole: false },
 			});
 
@@ -69,6 +80,7 @@ describe("Plugin Configuration", () => {
 			expect(config).toEqual({
 				codexMode: false,
 				enablePromptCaching: true,
+				appendEnvContext: false,
 				logging: { showWarningToasts: false, logWarningsToConsole: false },
 			});
 		});
@@ -82,10 +94,30 @@ describe("Plugin Configuration", () => {
 			expect(config).toEqual({
 				codexMode: true,
 				enablePromptCaching: true,
+				appendEnvContext: false,
 				logging: { showWarningToasts: false, logWarningsToConsole: false },
 			});
 		});
 
+		it("should default appendEnvContext from env when config missing", () => {
+			process.env.CODEX_APPEND_ENV_CONTEXT = "1";
+			mockExistsSync.mockReturnValue(false);
+
+			const config = loadPluginConfig({ forceReload: true });
+
+			expect(config.appendEnvContext).toBe(true);
+		});
+
+		it("should let config override appendEnvContext even when env is set", () => {
+			process.env.CODEX_APPEND_ENV_CONTEXT = "1";
+			mockExistsSync.mockReturnValue(true);
+			mockReadFileSync.mockReturnValue(JSON.stringify({ appendEnvContext: false }));
+
+			const config = loadPluginConfig({ forceReload: true });
+
+			expect(config.appendEnvContext).toBe(false);
+		});
+
 		it("should merge nested logging config with defaults", () => {
 			mockExistsSync.mockReturnValue(true);
 			mockReadFileSync.mockReturnValue(
@@ -112,6 +144,7 @@ describe("Plugin Configuration", () => {
 			expect(config).toEqual({
 				codexMode: true,
 				enablePromptCaching: true,
+				appendEnvContext: false,
 				logging: { showWarningToasts: false, logWarningsToConsole: false },
 			});
 
@@ -131,6 +164,7 @@ describe("Plugin Configuration", () => {
 			expect(config).toEqual({
 				codexMode: true,
 				enablePromptCaching: true,
+				appendEnvContext: false,
 				logging: { showWarningToasts: false, logWarningsToConsole: false },
 			});
 			expect(logWarnSpy).toHaveBeenCalled();

test/request-transformer.test.ts

@@ -714,7 +714,14 @@ describe("transformRequestBody caching stability", () => {
 			],
 		};
 
-		const result1 = await transformRequestBody(body1, CODEX_INSTRUCTIONS, userConfig, true, {}, undefined);
+		const result1 = await transformRequestBody(
+			body1,
+			CODEX_INSTRUCTIONS,
+			userConfig,
+			true,
+			{ appendEnvContext: false },
+			undefined,
+		);
 		expect(result1.prompt_cache_key).toContain("conv-env-stable");
 		expect(result1.input).toHaveLength(1);
 		expect(result1.input?.[0].role).toBe("user");
@@ -728,14 +735,20 @@ describe("transformRequestBody caching stability", () => {
 			],
 		};
 
-		const result2 = await transformRequestBody(body2, CODEX_INSTRUCTIONS, userConfig, true, {}, undefined);
+		const result2 = await transformRequestBody(
+			body2,
+			CODEX_INSTRUCTIONS,
+			userConfig,
+			true,
+			{ appendEnvContext: false },
+			undefined,
+		);
 		expect(result2.prompt_cache_key).toBe(result1.prompt_cache_key);
 		expect(result2.input).toHaveLength(1);
 		expect(result2.input?.[0].role).toBe("user");
 	});
 
 	it("can reattach env/files tail when flag enabled", async () => {
-		process.env.CODEX_APPEND_ENV_CONTEXT = "1";
 		const body: RequestBody = {
 			model: "gpt-5",
 			metadata: { conversation_id: "conv-env-tail" },
@@ -762,14 +775,19 @@ describe("transformRequestBody caching stability", () => {
 			],
 		};
 
-		const result = await transformRequestBody(body, CODEX_INSTRUCTIONS, userConfig, true, {}, undefined);
+		const result = await transformRequestBody(
+			body,
+			CODEX_INSTRUCTIONS,
+			userConfig,
+			true,
+			{ appendEnvContext: true },
+			undefined,
+		);
 		expect(result.input?.length).toBe(2);
 		expect(result.input?.[0].role).toBe("user");
 		expect(result.input?.[1].role).toBe("developer");
 		expect(result.input?.[1].content as string).toContain("<env>");
 		expect(result.input?.[1].content as string).toContain("<files>");
-
-		delete process.env.CODEX_APPEND_ENV_CONTEXT;
 	});
 });