Add MiniMax provider support (#656 by @dannote)

- Add minimax to KnownProvider and Api types
- Add MINIMAX_API_KEY to getEnvApiKey()
- Generate MiniMax-M2 and MiniMax-M2.1 models
- Add context overflow detection pattern
- Add tests to all required test files
- Update README and CHANGELOG with attribution

Also fixes:
- Bedrock duplicate toolResult ID when content has multiple blocks
- Sandbox extension unused parameter lint warning

packages/ai/test/abort.test.ts

@@ -160,6 +160,18 @@ describe("AI Providers Abort Tests", () => {
 		});
 	});
 
+	describe.skipIf(!process.env.MINIMAX_API_KEY)("MiniMax Provider Abort", () => {
+		const llm = getModel("minimax", "MiniMax-M2.1");
+
+		it("should abort mid-stream", { retry: 3 }, async () => {
+			await testAbortSignal(llm);
+		});
+
+		it("should handle immediate abort", { retry: 3 }, async () => {
+			await testImmediateAbort(llm);
+		});
+	});
+
 	// Google Gemini CLI / Antigravity share the same provider, so one test covers both
 	describe("Google Gemini CLI Provider Abort", () => {
 		it.skipIf(!geminiCliToken)("should abort mid-stream", { retry: 3 }, async () => {

packages/ai/test/context-overflow.test.ts

@@ -396,6 +396,22 @@ describe("Context overflow error handling", () => {
 		}, 120000);
 	});
 
+	// =============================================================================
+	// MiniMax
+	// Expected pattern: TBD - need to test actual error message
+	// =============================================================================
+
+	describe.skipIf(!process.env.MINIMAX_API_KEY)("MiniMax", () => {
+		it("MiniMax-M2.1 - should detect overflow via isContextOverflow", async () => {
+			const model = getModel("minimax", "MiniMax-M2.1");
+			const result = await testContextOverflow(model, process.env.MINIMAX_API_KEY!);
+			logResult(result);
+
+			expect(result.stopReason).toBe("error");
+			expect(isContextOverflow(result.response, model.contextWindow)).toBe(true);
+		}, 120000);
+	});
+
 	// =============================================================================
 	// OpenRouter - Multiple backend providers
 	// Expected pattern: "maximum context length is X tokens"

packages/ai/test/empty.test.ts

@@ -322,6 +322,26 @@ describe("AI Providers Empty Message Tests", () => {
 		});
 	});
 
+	describe.skipIf(!process.env.MINIMAX_API_KEY)("MiniMax Provider Empty Messages", () => {
+		const llm = getModel("minimax", "MiniMax-M2.1");
+
+		it("should handle empty content array", { retry: 3, timeout: 30000 }, async () => {
+			await testEmptyMessage(llm);
+		});
+
+		it("should handle empty string content", { retry: 3, timeout: 30000 }, async () => {
+			await testEmptyStringMessage(llm);
+		});
+
+		it("should handle whitespace-only content", { retry: 3, timeout: 30000 }, async () => {
+			await testWhitespaceOnlyMessage(llm);
+		});
+
+		it("should handle empty assistant message in conversation", { retry: 3, timeout: 30000 }, async () => {
+			await testEmptyAssistantMessage(llm);
+		});
+	});
+
 	describe.skipIf(!hasBedrockCredentials())("Amazon Bedrock Provider Empty Messages", () => {
 		const llm = getModel("amazon-bedrock", "global.anthropic.claude-sonnet-4-5-20250929-v1:0");
 

packages/ai/test/stream.test.ts

@@ -699,6 +699,30 @@ describe("Generate E2E Tests", () => {
 		});
 	});
 
+	describe.skipIf(!process.env.MINIMAX_API_KEY)("MiniMax Provider (MiniMax-M2.1 via Anthropic Messages)", () => {
+		const llm = getModel("minimax", "MiniMax-M2.1");
+
+		it("should complete basic text generation", { retry: 3 }, async () => {
+			await basicTextGeneration(llm);
+		});
+
+		it("should handle tool calling", { retry: 3 }, async () => {
+			await handleToolCall(llm);
+		});
+
+		it("should handle streaming", { retry: 3 }, async () => {
+			await handleStreaming(llm);
+		});
+
+		it("should handle thinking mode", { retry: 3 }, async () => {
+			await handleThinking(llm, { thinkingEnabled: true, thinkingBudgetTokens: 2048 });
+		});
+
+		it("should handle multi-turn with thinking and tools", { retry: 3 }, async () => {
+			await multiTurn(llm, { thinkingEnabled: true, thinkingBudgetTokens: 2048 });
+		});
+	});
+
 	// =========================================================================
 	// OAuth-based providers (credentials from ~/.pi/agent/oauth.json)
 	// Tokens are resolved at module level (see oauthTokens above)

packages/ai/test/tokens.test.ts

@@ -46,7 +46,8 @@ async function testTokensOnAbort<TApi extends Api>(llm: Model<TApi>, options: Op
 	expect(msg.stopReason).toBe("aborted");
 
 	// OpenAI providers, OpenAI Codex, Gemini CLI, zai, Amazon Bedrock, and the GPT-OSS model on Antigravity only send usage in the final chunk,
-	// so when aborted they have no token stats Anthropic and Google send usage information early in the stream
+	// so when aborted they have no token stats. Anthropic and Google send usage information early in the stream.
+	// MiniMax reports input tokens but not output tokens when aborted.
 	if (
 		llm.api === "openai-completions" ||
 		llm.api === "openai-responses" ||
@@ -58,6 +59,10 @@ async function testTokensOnAbort<TApi extends Api>(llm: Model<TApi>, options: Op
 	) {
 		expect(msg.usage.input).toBe(0);
 		expect(msg.usage.output).toBe(0);
+	} else if (llm.provider === "minimax") {
+		// MiniMax reports input tokens early but output tokens only in final chunk
+		expect(msg.usage.input).toBeGreaterThan(0);
+		expect(msg.usage.output).toBe(0);
 	} else {
 		expect(msg.usage.input).toBeGreaterThan(0);
 		expect(msg.usage.output).toBeGreaterThan(0);
@@ -146,6 +151,14 @@ describe("Token Statistics on Abort", () => {
 		});
 	});
 
+	describe.skipIf(!process.env.MINIMAX_API_KEY)("MiniMax Provider", () => {
+		const llm = getModel("minimax", "MiniMax-M2.1");
+
+		it("should include token stats when aborted mid-stream", { retry: 3, timeout: 30000 }, async () => {
+			await testTokensOnAbort(llm);
+		});
+	});
+
 	// =========================================================================
 	// OAuth-based providers (credentials from ~/.pi/agent/oauth.json)
 	// =========================================================================

packages/ai/test/tool-call-without-result.test.ts

@@ -171,6 +171,14 @@ describe("Tool Call Without Result Tests", () => {
 		});
 	});
 
+	describe.skipIf(!process.env.MINIMAX_API_KEY)("MiniMax Provider", () => {
+		const model = getModel("minimax", "MiniMax-M2.1");
+
+		it("should filter out tool calls without corresponding tool results", { retry: 3, timeout: 30000 }, async () => {
+			await testToolCallWithoutResult(model);
+		});
+	});
+
 	describe.skipIf(!hasBedrockCredentials())("Amazon Bedrock Provider", () => {
 		const model = getModel("amazon-bedrock", "global.anthropic.claude-sonnet-4-5-20250929-v1:0");
 

packages/ai/test/total-tokens.test.ts

@@ -325,6 +325,29 @@ describe("totalTokens field", () => {
 		);
 	});
 
+	// =========================================================================
+	// MiniMax
+	// =========================================================================
+
+	describe.skipIf(!process.env.MINIMAX_API_KEY)("MiniMax", () => {
+		it(
+			"MiniMax-M2.1 - should return totalTokens equal to sum of components",
+			{ retry: 3, timeout: 60000 },
+			async () => {
+				const llm = getModel("minimax", "MiniMax-M2.1");
+
+				console.log(`\nMiniMax / ${llm.id}:`);
+				const { first, second } = await testTotalTokensWithCache(llm, { apiKey: process.env.MINIMAX_API_KEY });
+
+				logUsage("First request", first);
+				logUsage("Second request", second);
+
+				assertTotalTokensEqualsComponents(first);
+				assertTotalTokensEqualsComponents(second);
+			},
+		);
+	});
+
 	// =========================================================================
 	// OpenRouter - Multiple backend providers
 	// =========================================================================

packages/ai/test/unicode-surrogate.test.ts

@@ -618,6 +618,22 @@ describe("AI Providers Unicode Surrogate Pair Tests", () => {
 		});
 	});
 
+	describe.skipIf(!process.env.MINIMAX_API_KEY)("MiniMax Provider Unicode Handling", () => {
+		const llm = getModel("minimax", "MiniMax-M2.1");
+
+		it("should handle emoji in tool results", { retry: 3, timeout: 30000 }, async () => {
+			await testEmojiInToolResults(llm);
+		});
+
+		it("should handle real-world LinkedIn comment data with emoji", { retry: 3, timeout: 30000 }, async () => {
+			await testRealWorldLinkedInData(llm);
+		});
+
+		it("should handle unpaired high surrogate (0xD83D) in tool results", { retry: 3, timeout: 30000 }, async () => {
+			await testUnpairedHighSurrogate(llm);
+		});
+	});
+
 	describe.skipIf(!hasBedrockCredentials())("Amazon Bedrock Provider Unicode Handling", () => {
 		const llm = getModel("amazon-bedrock", "global.anthropic.claude-sonnet-4-5-20250929-v1:0");