fix(ai): normalize pipe-separated tool call IDs for cross-provider handoff

- Handle pipe-separated IDs from OpenAI Responses API in openai-completions provider
- Strip trailing underscores after truncation in openai-responses-shared (OpenAI Codex rejects them)
- Add regression tests for tool call ID normalization

fixes #1022

packages/ai/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Fixed
 
+- Fixed cross-provider handoff failing when switching from OpenAI Responses API providers (github-copilot, openai-codex) to other providers due to pipe-separated tool call IDs not being normalized, and trailing underscores in truncated IDs being rejected by OpenAI Codex ([#1022](https://github.com/badlogic/pi-mono/issues/1022))
 - Fixed 429 rate limit errors incorrectly triggering auto-compaction instead of retry with backoff ([#1038](https://github.com/badlogic/pi-mono/issues/1038))
 - Fixed Anthropic provider to handle `sensitive` stop_reason returned by API ([#978](https://github.com/badlogic/pi-mono/issues/978))
 - Fixed DeepSeek API compatibility by detecting `deepseek.com` URLs and disabling unsupported `developer` role ([#1048](https://github.com/badlogic/pi-mono/issues/1048))

packages/ai/src/providers/openai-completions.ts

@@ -497,6 +497,17 @@ export function convertMessages(
 
 	const normalizeToolCallId = (id: string): string => {
 		if (compat.requiresMistralToolIds) return normalizeMistralToolId(id);
+
+		// Handle pipe-separated IDs from OpenAI Responses API
+		// Format: {call_id}|{id} where {id} can be 400+ chars with special chars (+, /, =)
+		// These come from providers like github-copilot, openai-codex, opencode
+		// Extract just the call_id part and normalize it
+		if (id.includes("|")) {
+			const [callId] = id.split("|");
+			// Sanitize to allowed chars and truncate to 40 chars (OpenAI limit)
+			return callId.replace(/[^a-zA-Z0-9_-]/g, "_").slice(0, 40);
+		}
+
 		if (model.provider === "openai") return id.length > 40 ? id.slice(0, 40) : id;
 		// Copilot Claude models route to Claude backend which requires Anthropic ID format
 		if (model.provider === "github-copilot" && model.id.toLowerCase().includes("claude")) {

packages/ai/src/providers/openai-responses-shared.ts

@@ -86,8 +86,11 @@ export function convertResponsesMessages<TApi extends Api>(
 		if (!sanitizedItemId.startsWith("fc")) {
 			sanitizedItemId = `fc_${sanitizedItemId}`;
 		}
-		const normalizedCallId = sanitizedCallId.length > 64 ? sanitizedCallId.slice(0, 64) : sanitizedCallId;
-		const normalizedItemId = sanitizedItemId.length > 64 ? sanitizedItemId.slice(0, 64) : sanitizedItemId;
+		// Truncate to 64 chars and strip trailing underscores (OpenAI Codex rejects them)
+		let normalizedCallId = sanitizedCallId.length > 64 ? sanitizedCallId.slice(0, 64) : sanitizedCallId;
+		let normalizedItemId = sanitizedItemId.length > 64 ? sanitizedItemId.slice(0, 64) : sanitizedItemId;
+		normalizedCallId = normalizedCallId.replace(/_+$/, "");
+		normalizedItemId = normalizedItemId.replace(/_+$/, "");
 		return `${normalizedCallId}|${normalizedItemId}`;
 	};
 

packages/ai/test/tool-call-id-normalization.test.ts

@@ -0,0 +1,291 @@
+/**
+ * Tool Call ID Normalization Tests
+ *
+ * Tests that tool call IDs from OpenAI Responses API (github-copilot, openai-codex, opencode)
+ * are properly normalized when sent to other providers.
+ *
+ * OpenAI Responses API generates IDs in format: {call_id}|{id}
+ * where {id} can be 400+ chars with special characters (+, /, =).
+ *
+ * Regression test for: https://github.com/badlogic/pi-mono/issues/1022
+ */
+
+import { Type } from "@sinclair/typebox";
+import { describe, expect, it } from "vitest";
+import { getModel } from "../src/models.js";
+import { completeSimple, getEnvApiKey } from "../src/stream.js";
+import type { AssistantMessage, Message, Tool, ToolResultMessage } from "../src/types.js";
+import { resolveApiKey } from "./oauth.js";
+
+// Resolve API keys
+const copilotToken = await resolveApiKey("github-copilot");
+const openrouterKey = getEnvApiKey("openrouter");
+const codexToken = await resolveApiKey("openai-codex");
+
+// Simple echo tool for testing
+const echoToolSchema = Type.Object({
+	message: Type.String({ description: "Message to echo back" }),
+});
+
+const echoTool: Tool<typeof echoToolSchema> = {
+	name: "echo",
+	description: "Echoes the message back",
+	parameters: echoToolSchema,
+};
+
+/**
+ * Test 1: Live cross-provider handoff
+ *
+ * 1. Use github-copilot gpt-5.2-codex to generate a tool call
+ * 2. Switch to openrouter openai/gpt-5.2-codex and complete
+ * 3. Switch to openai-codex gpt-5.2-codex and complete
+ *
+ * Both should succeed without "call_id too long" errors.
+ */
+describe("Tool Call ID Normalization - Live Handoff", () => {
+	it.skipIf(!copilotToken || !openrouterKey)(
+		"github-copilot -> openrouter should normalize pipe-separated IDs",
+		async () => {
+			const copilotModel = getModel("github-copilot", "gpt-5.2-codex");
+			const openrouterModel = getModel("openrouter", "openai/gpt-5.2-codex");
+
+			// Step 1: Generate tool call with github-copilot
+			const userMessage: Message = {
+				role: "user",
+				content: "Use the echo tool to echo 'hello world'",
+				timestamp: Date.now(),
+			};
+
+			const assistantResponse = await completeSimple(
+				copilotModel,
+				{
+					systemPrompt: "You are a helpful assistant. Use the echo tool when asked.",
+					messages: [userMessage],
+					tools: [echoTool],
+				},
+				{ apiKey: copilotToken },
+			);
+
+			expect(assistantResponse.stopReason, `Copilot error: ${assistantResponse.errorMessage}`).toBe("toolUse");
+
+			const toolCall = assistantResponse.content.find((c) => c.type === "toolCall");
+			expect(toolCall).toBeDefined();
+			expect(toolCall!.type).toBe("toolCall");
+
+			// Verify it's a pipe-separated ID (OpenAI Responses format)
+			if (toolCall?.type === "toolCall") {
+				expect(toolCall.id).toContain("|");
+				console.log(`Tool call ID from github-copilot: ${toolCall.id.slice(0, 80)}...`);
+			}
+
+			// Create tool result
+			const toolResult: ToolResultMessage = {
+				role: "toolResult",
+				toolCallId: (toolCall as any).id,
+				toolName: "echo",
+				content: [{ type: "text", text: "hello world" }],
+				isError: false,
+				timestamp: Date.now(),
+			};
+
+			// Step 2: Complete with openrouter (uses openai-completions API)
+			const openrouterResponse = await completeSimple(
+				openrouterModel,
+				{
+					systemPrompt: "You are a helpful assistant.",
+					messages: [
+						userMessage,
+						assistantResponse,
+						toolResult,
+						{ role: "user", content: "Say hi", timestamp: Date.now() },
+					],
+					tools: [echoTool],
+				},
+				{ apiKey: openrouterKey },
+			);
+
+			// Should NOT fail with "call_id too long" error
+			expect(openrouterResponse.stopReason, `OpenRouter error: ${openrouterResponse.errorMessage}`).not.toBe(
+				"error",
+			);
+			expect(openrouterResponse.errorMessage).toBeUndefined();
+		},
+		60000,
+	);
+
+	it.skipIf(!copilotToken || !codexToken)(
+		"github-copilot -> openai-codex should normalize pipe-separated IDs",
+		async () => {
+			const copilotModel = getModel("github-copilot", "gpt-5.2-codex");
+			const codexModel = getModel("openai-codex", "gpt-5.2-codex");
+
+			// Step 1: Generate tool call with github-copilot
+			const userMessage: Message = {
+				role: "user",
+				content: "Use the echo tool to echo 'test message'",
+				timestamp: Date.now(),
+			};
+
+			const assistantResponse = await completeSimple(
+				copilotModel,
+				{
+					systemPrompt: "You are a helpful assistant. Use the echo tool when asked.",
+					messages: [userMessage],
+					tools: [echoTool],
+				},
+				{ apiKey: copilotToken },
+			);
+
+			expect(assistantResponse.stopReason, `Copilot error: ${assistantResponse.errorMessage}`).toBe("toolUse");
+
+			const toolCall = assistantResponse.content.find((c) => c.type === "toolCall");
+			expect(toolCall).toBeDefined();
+
+			// Create tool result
+			const toolResult: ToolResultMessage = {
+				role: "toolResult",
+				toolCallId: (toolCall as any).id,
+				toolName: "echo",
+				content: [{ type: "text", text: "test message" }],
+				isError: false,
+				timestamp: Date.now(),
+			};
+
+			// Step 2: Complete with openai-codex (uses openai-codex-responses API)
+			const codexResponse = await completeSimple(
+				codexModel,
+				{
+					systemPrompt: "You are a helpful assistant.",
+					messages: [
+						userMessage,
+						assistantResponse,
+						toolResult,
+						{ role: "user", content: "Say hi", timestamp: Date.now() },
+					],
+					tools: [echoTool],
+				},
+				{ apiKey: codexToken },
+			);
+
+			// Should NOT fail with ID validation error
+			expect(codexResponse.stopReason, `Codex error: ${codexResponse.errorMessage}`).not.toBe("error");
+			expect(codexResponse.errorMessage).toBeUndefined();
+		},
+		60000,
+	);
+});
+
+/**
+ * Test 2: Prefilled context with exact failing IDs from issue #1022
+ *
+ * Uses the exact tool call ID format that caused the error:
+ * "call_xxx|very_long_base64_with_special_chars+/="
+ */
+describe("Tool Call ID Normalization - Prefilled Context", () => {
+	// Exact tool call ID from issue #1022 JSONL
+	const FAILING_TOOL_CALL_ID =
+		"call_pAYbIr76hXIjncD9UE4eGfnS|t5nnb2qYMFWGSsr13fhCd1CaCu3t3qONEPuOudu4HSVEtA8YJSL6FAZUxvoOoD792VIJWl91g87EdqsCWp9krVsdBysQoDaf9lMCLb8BS4EYi4gQd5kBQBYLlgD71PYwvf+TbMD9J9/5OMD42oxSRj8H+vRf78/l2Xla33LWz4nOgsddBlbvabICRs8GHt5C9PK5keFtzyi3lsyVKNlfduK3iphsZqs4MLv4zyGJnvZo/+QzShyk5xnMSQX/f98+aEoNflEApCdEOXipipgeiNWnpFSHbcwmMkZoJhURNu+JEz3xCh1mrXeYoN5o+trLL3IXJacSsLYXDrYTipZZbJFRPAucgbnjYBC+/ZzJOfkwCs+Gkw7EoZR7ZQgJ8ma+9586n4tT4cI8DEhBSZsWMjrCt8dxKg==";
+
+	// Build prefilled context with the failing ID
+	function buildPrefilledMessages(): Message[] {
+		const userMessage: Message = {
+			role: "user",
+			content: "Use the echo tool to echo 'hello'",
+			timestamp: Date.now() - 2000,
+		};
+
+		const assistantMessage: AssistantMessage = {
+			role: "assistant",
+			content: [
+				{
+					type: "toolCall",
+					id: FAILING_TOOL_CALL_ID,
+					name: "echo",
+					arguments: { message: "hello" },
+				},
+			],
+			api: "openai-responses",
+			provider: "github-copilot",
+			model: "gpt-5.2-codex",
+			usage: {
+				input: 100,
+				output: 50,
+				cacheRead: 0,
+				cacheWrite: 0,
+				totalTokens: 150,
+				cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+			},
+			stopReason: "toolUse",
+			timestamp: Date.now() - 1500,
+		};
+
+		const toolResult: ToolResultMessage = {
+			role: "toolResult",
+			toolCallId: FAILING_TOOL_CALL_ID,
+			toolName: "echo",
+			content: [{ type: "text", text: "hello" }],
+			isError: false,
+			timestamp: Date.now() - 1000,
+		};
+
+		const followUpUser: Message = {
+			role: "user",
+			content: "Say hi",
+			timestamp: Date.now(),
+		};
+
+		return [userMessage, assistantMessage, toolResult, followUpUser];
+	}
+
+	it.skipIf(!openrouterKey)(
+		"openrouter should handle prefilled context with long pipe-separated IDs",
+		async () => {
+			const model = getModel("openrouter", "openai/gpt-5.2-codex");
+			const messages = buildPrefilledMessages();
+
+			const response = await completeSimple(
+				model,
+				{
+					systemPrompt: "You are a helpful assistant.",
+					messages,
+					tools: [echoTool],
+				},
+				{ apiKey: openrouterKey },
+			);
+
+			// Should NOT fail with "call_id too long" error
+			expect(response.stopReason, `OpenRouter error: ${response.errorMessage}`).not.toBe("error");
+			if (response.errorMessage) {
+				expect(response.errorMessage).not.toContain("call_id");
+				expect(response.errorMessage).not.toContain("too long");
+			}
+		},
+		30000,
+	);
+
+	it.skipIf(!codexToken)(
+		"openai-codex should handle prefilled context with long pipe-separated IDs",
+		async () => {
+			const model = getModel("openai-codex", "gpt-5.2-codex");
+			const messages = buildPrefilledMessages();
+
+			const response = await completeSimple(
+				model,
+				{
+					systemPrompt: "You are a helpful assistant.",
+					messages,
+					tools: [echoTool],
+				},
+				{ apiKey: codexToken },
+			);
+
+			// Should NOT fail with ID validation error
+			expect(response.stopReason, `Codex error: ${response.errorMessage}`).not.toBe("error");
+			if (response.errorMessage) {
+				expect(response.errorMessage).not.toContain("id");
+				expect(response.errorMessage).not.toContain("additional characters");
+			}
+		},
+		30000,
+	);
+});