feat(ai): add OpenAI Codex OAuth + responses provider

packages/ai/src/providers/openai-codex/prompts/codex.ts

@@ -0,0 +1,227 @@
+import { existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
+import { homedir } from "node:os";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const GITHUB_API_RELEASES = "https://api.github.com/repos/openai/codex/releases/latest";
+const GITHUB_HTML_RELEASES = "https://github.com/openai/codex/releases/latest";
+
+const DEFAULT_AGENT_DIR = join(homedir(), ".pi", "agent");
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+const FALLBACK_PROMPT_PATH = join(__dirname, "codex-instructions.md");
+
+function getAgentDir(): string {
+	return process.env.PI_CODING_AGENT_DIR || DEFAULT_AGENT_DIR;
+}
+
+function getCacheDir(): string {
+	return join(getAgentDir(), "cache", "openai-codex");
+}
+
+export type ModelFamily = "gpt-5.2-codex" | "codex-max" | "codex" | "gpt-5.2" | "gpt-5.1";
+
+const PROMPT_FILES: Record<ModelFamily, string> = {
+	"gpt-5.2-codex": "gpt-5.2-codex_prompt.md",
+	"codex-max": "gpt-5.1-codex-max_prompt.md",
+	codex: "gpt_5_codex_prompt.md",
+	"gpt-5.2": "gpt_5_2_prompt.md",
+	"gpt-5.1": "gpt_5_1_prompt.md",
+};
+
+const CACHE_FILES: Record<ModelFamily, string> = {
+	"gpt-5.2-codex": "gpt-5.2-codex-instructions.md",
+	"codex-max": "codex-max-instructions.md",
+	codex: "codex-instructions.md",
+	"gpt-5.2": "gpt-5.2-instructions.md",
+	"gpt-5.1": "gpt-5.1-instructions.md",
+};
+
+export type CacheMetadata = {
+	etag: string | null;
+	tag: string;
+	lastChecked: number;
+	url: string;
+};
+
+export function getModelFamily(normalizedModel: string): ModelFamily {
+	if (normalizedModel.includes("gpt-5.2-codex") || normalizedModel.includes("gpt 5.2 codex")) {
+		return "gpt-5.2-codex";
+	}
+	if (normalizedModel.includes("codex-max")) {
+		return "codex-max";
+	}
+	if (normalizedModel.includes("codex") || normalizedModel.startsWith("codex-")) {
+		return "codex";
+	}
+	if (normalizedModel.includes("gpt-5.2")) {
+		return "gpt-5.2";
+	}
+	return "gpt-5.1";
+}
+
+async function getLatestReleaseTag(): Promise<string> {
+	try {
+		const response = await fetch(GITHUB_API_RELEASES);
+		if (response.ok) {
+			const data = (await response.json()) as { tag_name?: string };
+			if (data.tag_name) {
+				return data.tag_name;
+			}
+		}
+	} catch {
+		// fallback
+	}
+
+	const htmlResponse = await fetch(GITHUB_HTML_RELEASES);
+	if (!htmlResponse.ok) {
+		throw new Error(`Failed to fetch latest release: ${htmlResponse.status}`);
+	}
+
+	const finalUrl = htmlResponse.url;
+	if (finalUrl) {
+		const parts = finalUrl.split("/tag/");
+		const last = parts[parts.length - 1];
+		if (last && !last.includes("/")) {
+			return last;
+		}
+	}
+
+	const html = await htmlResponse.text();
+	const match = html.match(/\/openai\/codex\/releases\/tag\/([^"]+)/);
+	if (match?.[1]) {
+		return match[1];
+	}
+
+	throw new Error("Failed to determine latest release tag from GitHub");
+}
+
+export async function getCodexInstructions(normalizedModel = "gpt-5.1-codex"): Promise<string> {
+	const modelFamily = getModelFamily(normalizedModel);
+	const promptFile = PROMPT_FILES[modelFamily];
+	const cacheDir = getCacheDir();
+	const cacheFile = join(cacheDir, CACHE_FILES[modelFamily]);
+	const cacheMetaFile = join(cacheDir, `${CACHE_FILES[modelFamily].replace(".md", "-meta.json")}`);
+
+	try {
+		let cachedETag: string | null = null;
+		let cachedTag: string | null = null;
+		let cachedTimestamp: number | null = null;
+
+		if (existsSync(cacheMetaFile)) {
+			const metadata = JSON.parse(readFileSync(cacheMetaFile, "utf8")) as CacheMetadata;
+			cachedETag = metadata.etag;
+			cachedTag = metadata.tag;
+			cachedTimestamp = metadata.lastChecked;
+		}
+
+		const CACHE_TTL_MS = 15 * 60 * 1000;
+		if (cachedTimestamp && Date.now() - cachedTimestamp < CACHE_TTL_MS && existsSync(cacheFile)) {
+			return readFileSync(cacheFile, "utf8");
+		}
+
+		const latestTag = await getLatestReleaseTag();
+		const instructionsUrl = `https://raw.githubusercontent.com/openai/codex/${latestTag}/codex-rs/core/${promptFile}`;
+
+		if (cachedTag !== latestTag) {
+			cachedETag = null;
+		}
+
+		const headers: Record<string, string> = {};
+		if (cachedETag) {
+			headers["If-None-Match"] = cachedETag;
+		}
+
+		const response = await fetch(instructionsUrl, { headers });
+
+		if (response.status === 304) {
+			if (existsSync(cacheFile)) {
+				return readFileSync(cacheFile, "utf8");
+			}
+		}
+
+		if (response.ok) {
+			const instructions = await response.text();
+			const newETag = response.headers.get("etag");
+
+			if (!existsSync(cacheDir)) {
+				mkdirSync(cacheDir, { recursive: true });
+			}
+
+			writeFileSync(cacheFile, instructions, "utf8");
+			writeFileSync(
+				cacheMetaFile,
+				JSON.stringify({
+					etag: newETag,
+					tag: latestTag,
+					lastChecked: Date.now(),
+					url: instructionsUrl,
+				} satisfies CacheMetadata),
+				"utf8",
+			);
+
+			return instructions;
+		}
+
+		throw new Error(`HTTP ${response.status}`);
+	} catch (error) {
+		console.error(
+			`[openai-codex] Failed to fetch ${modelFamily} instructions from GitHub:`,
+			error instanceof Error ? error.message : String(error),
+		);
+
+		if (existsSync(cacheFile)) {
+			console.error(`[openai-codex] Using cached ${modelFamily} instructions`);
+			return readFileSync(cacheFile, "utf8");
+		}
+
+		if (existsSync(FALLBACK_PROMPT_PATH)) {
+			console.error(`[openai-codex] Falling back to bundled instructions for ${modelFamily}`);
+			return readFileSync(FALLBACK_PROMPT_PATH, "utf8");
+		}
+
+		throw new Error(`No cached Codex instructions available for ${modelFamily}`);
+	}
+}
+
+export const TOOL_REMAP_MESSAGE = `<user_instructions priority="0">
+<environment_override priority="0">
+YOU ARE IN A DIFFERENT ENVIRONMENT. These instructions override ALL previous tool references.
+</environment_override>
+
+<tool_replacements priority="0">
+<critical_rule priority="0">
+❌ APPLY_PATCH DOES NOT EXIST → ✅ USE "edit" INSTEAD
+- NEVER use: apply_patch, applyPatch
+- ALWAYS use: edit tool for ALL file modifications
+</critical_rule>
+
+<critical_rule priority="0">
+❌ UPDATE_PLAN DOES NOT EXIST
+- NEVER use: update_plan, updatePlan, read_plan, readPlan, todowrite, todoread
+- There is no plan tool in this environment
+</critical_rule>
+</tool_replacements>
+
+<available_tools priority="0">
+File Operations:
+  • read  - Read file contents
+  • edit  - Modify files with exact find/replace
+  • write - Create or overwrite files
+
+Search/Discovery:
+  • grep  - Search file contents for patterns (read-only)
+  • find  - Find files by glob pattern (read-only)
+  • ls    - List directory contents (read-only)
+
+Execution:
+  • bash  - Run shell commands
+</available_tools>
+
+<verification_checklist priority="0">
+Before file modifications:
+1. Am I using "edit" NOT "apply_patch"?
+2. Am I avoiding plan tools entirely?
+3. Am I using only the tools listed above?
+</verification_checklist>
+</user_instructions>`;