feat: initial impl

- add GitHub Copilot model discovery (env token fallback, headers,
compat) plus fallback list and quoted provider keys in generated map
- surface Copilot provider end-to-end (KnownProvider/default, env+OAuth
token refresh/save, enterprise base URL swap, available only when
creds/env exist)
- tweak interactive OAuth UI to render instruction text and prompt
placeholders

gpt-5.2-high took about 35 minutes. It had a lot of trouble with `npm
check`  and went off on a "let's adjust every tsconfig" side quest.
Device code flow works, but the ai/scripts/generate-models.ts impl is
wrong as models from months ago are missing and only those deprecated
are accessible in the /models picker.

packages/ai/scripts/generate-models.ts

@@ -29,6 +29,162 @@ interface ModelsDevModel {
 	};
 }
 
+const COPILOT_STATIC_HEADERS = {
+	"User-Agent": "GitHubCopilotChat/0.35.0",
+	"Editor-Version": "vscode/1.105.1",
+	"Editor-Plugin-Version": "copilot-chat/0.35.0",
+	"Copilot-Integration-Id": "copilot-developer-cli",
+	"Openai-Intent": "conversation-edits",
+	"X-Initiator": "agent",
+} as const;
+
+function getGitHubTokenFromEnv(): string | null {
+	return process.env.COPILOT_GITHUB_TOKEN || process.env.GH_TOKEN || process.env.GITHUB_TOKEN || null;
+}
+
+function isDeprecatedCopilotModel(model: unknown): boolean {
+	if (!model || typeof model !== "object") return false;
+	const m = model as Record<string, unknown>;
+	if (m.deprecated === true) return true;
+	if (m.is_deprecated === true) return true;
+	if (m.status === "deprecated") return true;
+	if (m.lifecycle === "deprecated") return true;
+	const id = typeof m.id === "string" ? m.id : "";
+	return id.includes("deprecated");
+}
+
+function supportsToolsCopilotModel(model: unknown): boolean {
+	if (!model || typeof model !== "object") return true;
+	const m = model as Record<string, unknown>;
+	const caps = m.capabilities;
+	if (!caps || typeof caps !== "object") return true;
+	const tools = (caps as Record<string, unknown>).tools;
+	if (tools === undefined) return true;
+	return tools !== false;
+}
+
+function supportsVisionCopilotModel(model: unknown): boolean {
+	if (!model || typeof model !== "object") return false;
+	const m = model as Record<string, unknown>;
+	const caps = m.capabilities;
+	if (!caps || typeof caps !== "object") return false;
+	const vision = (caps as Record<string, unknown>).vision;
+	if (vision === true) return true;
+	const modalities = (caps as Record<string, unknown>).modalities;
+	if (Array.isArray(modalities)) return modalities.includes("vision") || modalities.includes("image");
+	return false;
+}
+
+function getNumberField(model: unknown, keys: string[], fallback: number): number {
+	if (!model || typeof model !== "object") return fallback;
+	const m = model as Record<string, unknown>;
+	for (const key of keys) {
+		const value = m[key];
+		if (typeof value === "number" && Number.isFinite(value)) return value;
+	}
+	return fallback;
+}
+
+async function fetchCopilotModels(githubToken: string): Promise<Model<any>[]> {
+	try {
+		console.log("Fetching models from GitHub Copilot API...");
+		const response = await fetch("https://api.githubcopilot.com/models", {
+			headers: {
+				Accept: "application/json",
+				Authorization: `Bearer ${githubToken}`,
+				...COPILOT_STATIC_HEADERS,
+			},
+		});
+
+		if (!response.ok) {
+			const text = await response.text();
+			console.warn(`Failed to fetch GitHub Copilot models: ${response.status} ${text}`);
+			return [];
+		}
+
+		const data = (await response.json()) as unknown;
+		const list =
+			Array.isArray(data) ? data : Array.isArray((data as any)?.models) ? (data as any).models : (data as any)?.data;
+		if (!Array.isArray(list)) {
+			console.warn("Failed to parse GitHub Copilot models response");
+			return [];
+		}
+
+		const models: Model<any>[] = [];
+
+		for (const item of list) {
+			if (isDeprecatedCopilotModel(item)) continue;
+			if (!supportsToolsCopilotModel(item)) continue;
+
+			const id = typeof (item as any)?.id === "string" ? (item as any).id : typeof item === "string" ? item : null;
+			if (!id) continue;
+
+			const name = typeof (item as any)?.name === "string" ? (item as any).name : id;
+			const contextWindow = getNumberField(item, ["context_window", "contextWindow", "max_context_tokens"], 128000);
+			const maxTokens = getNumberField(item, ["max_output_tokens", "maxTokens", "max_tokens"], 8192);
+			const input: ("text" | "image")[] = supportsVisionCopilotModel(item) ? ["text", "image"] : ["text"];
+
+			models.push({
+				id,
+				name,
+				api: "openai-completions",
+				provider: "github-copilot",
+				baseUrl: "https://api.githubcopilot.com",
+				reasoning: false,
+				input,
+				cost: {
+					input: 0,
+					output: 0,
+					cacheRead: 0,
+					cacheWrite: 0,
+				},
+				contextWindow,
+				maxTokens,
+				headers: { ...COPILOT_STATIC_HEADERS },
+				compat: {
+					supportsStore: false,
+					supportsDeveloperRole: false,
+					supportsReasoningEffort: false,
+				},
+			});
+		}
+
+		console.log(`Fetched ${models.length} models from GitHub Copilot`);
+		return models;
+	} catch (error) {
+		console.warn("Failed to fetch GitHub Copilot models:", error);
+		return [];
+	}
+}
+
+function getFallbackCopilotModels(): Model<any>[] {
+	const fallbackModelIds = ["gpt-4o", "gpt-4o-mini", "claude-3.5-sonnet", "o1", "o1-mini"];
+
+	return fallbackModelIds.map((id) => ({
+		id,
+		name: id,
+		api: "openai-completions",
+		provider: "github-copilot",
+		baseUrl: "https://api.githubcopilot.com",
+		reasoning: false,
+		input: ["text"],
+		cost: {
+			input: 0,
+			output: 0,
+			cacheRead: 0,
+			cacheWrite: 0,
+		},
+		contextWindow: 128000,
+		maxTokens: 8192,
+		headers: { ...COPILOT_STATIC_HEADERS },
+		compat: {
+			supportsStore: false,
+			supportsDeveloperRole: false,
+			supportsReasoningEffort: false,
+		},
+	}));
+}
+
 async function fetchOpenRouterModels(): Promise<Model<any>[]> {
 	try {
 		console.log("Fetching models from OpenRouter API...");
@@ -321,6 +477,20 @@ async function generateModels() {
 	// Combine models (models.dev has priority)
 	const allModels = [...modelsDevModels, ...openRouterModels];
 
+	const githubToken = getGitHubTokenFromEnv();
+	let copilotModels: Model<any>[] = [];
+	if (!githubToken) {
+		console.warn("No GitHub token found for GitHub Copilot model discovery (set COPILOT_GITHUB_TOKEN, GH_TOKEN, or GITHUB_TOKEN). Using fallback list.");
+		copilotModels = getFallbackCopilotModels();
+	} else {
+		copilotModels = await fetchCopilotModels(githubToken);
+		if (copilotModels.length === 0) {
+			console.warn("No GitHub Copilot models fetched. Using fallback list.");
+			copilotModels = getFallbackCopilotModels();
+		}
+	}
+	allModels.push(...copilotModels);
+
 	// Fix incorrect cache pricing for Claude Opus 4.5 from models.dev
 	// models.dev has 3x the correct pricing (1.5/18.75 instead of 0.5/6.25)
 	const opus45 = allModels.find(m => m.provider === "anthropic" && m.id === "claude-opus-4-5");
@@ -458,7 +628,7 @@ export const MODELS = {
 
 	// Generate provider sections
 	for (const [providerId, models] of Object.entries(providers)) {
-		output += `\t${providerId}: {\n`;
+		output += `\t${JSON.stringify(providerId)}: {\n`;
 
 		for (const model of Object.values(models)) {
 			output += `\t\t"${model.id}": {\n`;
@@ -469,6 +639,12 @@ export const MODELS = {
 			if (model.baseUrl) {
 				output += `\t\t\tbaseUrl: "${model.baseUrl}",\n`;
 			}
+			if (model.headers) {
+				output += `\t\t\theaders: ${JSON.stringify(model.headers)},\n`;
+			}
+			if ((model as any).compat) {
+				output += `\t\t\tcompat: ${JSON.stringify((model as any).compat)},\n`;
+			}
 			output += `\t\t\treasoning: ${model.reasoning},\n`;
 			output += `\t\t\tinput: [${model.input.map(i => `"${i}"`).join(", ")}],\n`;
 			output += `\t\t\tcost: {\n`;

packages/ai/src/models.generated.ts

@@ -5733,23 +5733,6 @@ export const MODELS = {
 			contextWindow: 32768,
 			maxTokens: 4096,
 		} satisfies Model<"openai-completions">,
-		"cohere/command-r-08-2024": {
-			id: "cohere/command-r-08-2024",
-			name: "Cohere: Command R (08-2024)",
-			api: "openai-completions",
-			provider: "openrouter",
-			baseUrl: "https://openrouter.ai/api/v1",
-			reasoning: false,
-			input: ["text"],
-			cost: {
-				input: 0.15,
-				output: 0.6,
-				cacheRead: 0,
-				cacheWrite: 0,
-			},
-			contextWindow: 128000,
-			maxTokens: 4000,
-		} satisfies Model<"openai-completions">,
 		"cohere/command-r-plus-08-2024": {
 			id: "cohere/command-r-plus-08-2024",
 			name: "Cohere: Command R+ (08-2024)",
@@ -5767,6 +5750,23 @@ export const MODELS = {
 			contextWindow: 128000,
 			maxTokens: 4000,
 		} satisfies Model<"openai-completions">,
+		"cohere/command-r-08-2024": {
+			id: "cohere/command-r-08-2024",
+			name: "Cohere: Command R (08-2024)",
+			api: "openai-completions",
+			provider: "openrouter",
+			baseUrl: "https://openrouter.ai/api/v1",
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 0.15,
+				output: 0.6,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 128000,
+			maxTokens: 4000,
+		} satisfies Model<"openai-completions">,
 		"sao10k/l3.1-euryale-70b": {
 			id: "sao10k/l3.1-euryale-70b",
 			name: "Sao10K: Llama 3.1 Euryale 70B v2.2",
@@ -5835,23 +5835,6 @@ export const MODELS = {
 			contextWindow: 131072,
 			maxTokens: 16384,
 		} satisfies Model<"openai-completions">,
-		"meta-llama/llama-3.1-405b-instruct": {
-			id: "meta-llama/llama-3.1-405b-instruct",
-			name: "Meta: Llama 3.1 405B Instruct",
-			api: "openai-completions",
-			provider: "openrouter",
-			baseUrl: "https://openrouter.ai/api/v1",
-			reasoning: false,
-			input: ["text"],
-			cost: {
-				input: 3.5,
-				output: 3.5,
-				cacheRead: 0,
-				cacheWrite: 0,
-			},
-			contextWindow: 130815,
-			maxTokens: 4096,
-		} satisfies Model<"openai-completions">,
 		"meta-llama/llama-3.1-70b-instruct": {
 			id: "meta-llama/llama-3.1-70b-instruct",
 			name: "Meta: Llama 3.1 70B Instruct",
@@ -5869,6 +5852,23 @@ export const MODELS = {
 			contextWindow: 131072,
 			maxTokens: 4096,
 		} satisfies Model<"openai-completions">,
+		"meta-llama/llama-3.1-405b-instruct": {
+			id: "meta-llama/llama-3.1-405b-instruct",
+			name: "Meta: Llama 3.1 405B Instruct",
+			api: "openai-completions",
+			provider: "openrouter",
+			baseUrl: "https://openrouter.ai/api/v1",
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 3.5,
+				output: 3.5,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 130815,
+			maxTokens: 4096,
+		} satisfies Model<"openai-completions">,
 		"mistralai/mistral-nemo": {
 			id: "mistralai/mistral-nemo",
 			name: "Mistral: Mistral Nemo",
@@ -5886,9 +5886,9 @@ export const MODELS = {
 			contextWindow: 131072,
 			maxTokens: 16384,
 		} satisfies Model<"openai-completions">,
-		"openai/gpt-4o-mini-2024-07-18": {
+		"openai/gpt-4o-mini": {
-			id: "openai/gpt-4o-mini-2024-07-18",
+			id: "openai/gpt-4o-mini",
-			name: "OpenAI: GPT-4o-mini (2024-07-18)",
+			name: "OpenAI: GPT-4o-mini",
 			api: "openai-completions",
 			provider: "openrouter",
 			baseUrl: "https://openrouter.ai/api/v1",
@@ -5903,9 +5903,9 @@ export const MODELS = {
 			contextWindow: 128000,
 			maxTokens: 16384,
 		} satisfies Model<"openai-completions">,
-		"openai/gpt-4o-mini": {
+		"openai/gpt-4o-mini-2024-07-18": {
-			id: "openai/gpt-4o-mini",
+			id: "openai/gpt-4o-mini-2024-07-18",
-			name: "OpenAI: GPT-4o-mini",
+			name: "OpenAI: GPT-4o-mini (2024-07-18)",
 			api: "openai-completions",
 			provider: "openrouter",
 			baseUrl: "https://openrouter.ai/api/v1",
@@ -6056,23 +6056,6 @@ export const MODELS = {
 			contextWindow: 128000,
 			maxTokens: 64000,
 		} satisfies Model<"openai-completions">,
-		"meta-llama/llama-3-70b-instruct": {
-			id: "meta-llama/llama-3-70b-instruct",
-			name: "Meta: Llama 3 70B Instruct",
-			api: "openai-completions",
-			provider: "openrouter",
-			baseUrl: "https://openrouter.ai/api/v1",
-			reasoning: false,
-			input: ["text"],
-			cost: {
-				input: 0.3,
-				output: 0.39999999999999997,
-				cacheRead: 0,
-				cacheWrite: 0,
-			},
-			contextWindow: 8192,
-			maxTokens: 16384,
-		} satisfies Model<"openai-completions">,
 		"meta-llama/llama-3-8b-instruct": {
 			id: "meta-llama/llama-3-8b-instruct",
 			name: "Meta: Llama 3 8B Instruct",
@@ -6090,6 +6073,23 @@ export const MODELS = {
 			contextWindow: 8192,
 			maxTokens: 16384,
 		} satisfies Model<"openai-completions">,
+		"meta-llama/llama-3-70b-instruct": {
+			id: "meta-llama/llama-3-70b-instruct",
+			name: "Meta: Llama 3 70B Instruct",
+			api: "openai-completions",
+			provider: "openrouter",
+			baseUrl: "https://openrouter.ai/api/v1",
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 0.3,
+				output: 0.39999999999999997,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 8192,
+			maxTokens: 16384,
+		} satisfies Model<"openai-completions">,
 		"mistralai/mixtral-8x22b-instruct": {
 			id: "mistralai/mixtral-8x22b-instruct",
 			name: "Mistral: Mixtral 8x22B Instruct",
@@ -6175,23 +6175,6 @@ export const MODELS = {
 			contextWindow: 128000,
 			maxTokens: 4096,
 		} satisfies Model<"openai-completions">,
-		"openai/gpt-3.5-turbo-0613": {
-			id: "openai/gpt-3.5-turbo-0613",
-			name: "OpenAI: GPT-3.5 Turbo (older v0613)",
-			api: "openai-completions",
-			provider: "openrouter",
-			baseUrl: "https://openrouter.ai/api/v1",
-			reasoning: false,
-			input: ["text"],
-			cost: {
-				input: 1,
-				output: 2,
-				cacheRead: 0,
-				cacheWrite: 0,
-			},
-			contextWindow: 4095,
-			maxTokens: 4096,
-		} satisfies Model<"openai-completions">,
 		"openai/gpt-4-turbo-preview": {
 			id: "openai/gpt-4-turbo-preview",
 			name: "OpenAI: GPT-4 Turbo Preview",
@@ -6209,6 +6192,23 @@ export const MODELS = {
 			contextWindow: 128000,
 			maxTokens: 4096,
 		} satisfies Model<"openai-completions">,
+		"openai/gpt-3.5-turbo-0613": {
+			id: "openai/gpt-3.5-turbo-0613",
+			name: "OpenAI: GPT-3.5 Turbo (older v0613)",
+			api: "openai-completions",
+			provider: "openrouter",
+			baseUrl: "https://openrouter.ai/api/v1",
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 1,
+				output: 2,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 4095,
+			maxTokens: 4096,
+		} satisfies Model<"openai-completions">,
 		"mistralai/mistral-tiny": {
 			id: "mistralai/mistral-tiny",
 			name: "Mistral Tiny",
@@ -6277,9 +6277,9 @@ export const MODELS = {
 			contextWindow: 16385,
 			maxTokens: 4096,
 		} satisfies Model<"openai-completions">,
-		"openai/gpt-4-0314": {
+		"openai/gpt-4": {
-			id: "openai/gpt-4-0314",
+			id: "openai/gpt-4",
-			name: "OpenAI: GPT-4 (older v0314)",
+			name: "OpenAI: GPT-4",
 			api: "openai-completions",
 			provider: "openrouter",
 			baseUrl: "https://openrouter.ai/api/v1",
@@ -6294,9 +6294,9 @@ export const MODELS = {
 			contextWindow: 8191,
 			maxTokens: 4096,
 		} satisfies Model<"openai-completions">,
-		"openai/gpt-4": {
+		"openai/gpt-4-0314": {
-			id: "openai/gpt-4",
+			id: "openai/gpt-4-0314",
-			name: "OpenAI: GPT-4",
+			name: "OpenAI: GPT-4 (older v0314)",
 			api: "openai-completions",
 			provider: "openrouter",
 			baseUrl: "https://openrouter.ai/api/v1",
@@ -6346,4 +6346,136 @@ export const MODELS = {
 			maxTokens: 30000,
 		} satisfies Model<"openai-completions">,
 	},
+	"github-copilot": {
+		"gpt-4o": {
+			id: "gpt-4o",
+			name: "gpt-4o",
+			api: "openai-completions",
+			provider: "github-copilot",
+			baseUrl: "https://api.githubcopilot.com",
+			headers: {
+				"User-Agent": "GitHubCopilotChat/0.35.0",
+				"Editor-Version": "vscode/1.105.1",
+				"Editor-Plugin-Version": "copilot-chat/0.35.0",
+				"Copilot-Integration-Id": "copilot-developer-cli",
+				"Openai-Intent": "conversation-edits",
+				"X-Initiator": "agent",
+			},
+			compat: { supportsStore: false, supportsDeveloperRole: false, supportsReasoningEffort: false },
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 0,
+				output: 0,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 128000,
+			maxTokens: 8192,
+		} satisfies Model<"openai-completions">,
+		"gpt-4o-mini": {
+			id: "gpt-4o-mini",
+			name: "gpt-4o-mini",
+			api: "openai-completions",
+			provider: "github-copilot",
+			baseUrl: "https://api.githubcopilot.com",
+			headers: {
+				"User-Agent": "GitHubCopilotChat/0.35.0",
+				"Editor-Version": "vscode/1.105.1",
+				"Editor-Plugin-Version": "copilot-chat/0.35.0",
+				"Copilot-Integration-Id": "copilot-developer-cli",
+				"Openai-Intent": "conversation-edits",
+				"X-Initiator": "agent",
+			},
+			compat: { supportsStore: false, supportsDeveloperRole: false, supportsReasoningEffort: false },
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 0,
+				output: 0,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 128000,
+			maxTokens: 8192,
+		} satisfies Model<"openai-completions">,
+		"claude-3.5-sonnet": {
+			id: "claude-3.5-sonnet",
+			name: "claude-3.5-sonnet",
+			api: "openai-completions",
+			provider: "github-copilot",
+			baseUrl: "https://api.githubcopilot.com",
+			headers: {
+				"User-Agent": "GitHubCopilotChat/0.35.0",
+				"Editor-Version": "vscode/1.105.1",
+				"Editor-Plugin-Version": "copilot-chat/0.35.0",
+				"Copilot-Integration-Id": "copilot-developer-cli",
+				"Openai-Intent": "conversation-edits",
+				"X-Initiator": "agent",
+			},
+			compat: { supportsStore: false, supportsDeveloperRole: false, supportsReasoningEffort: false },
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 0,
+				output: 0,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 128000,
+			maxTokens: 8192,
+		} satisfies Model<"openai-completions">,
+		o1: {
+			id: "o1",
+			name: "o1",
+			api: "openai-completions",
+			provider: "github-copilot",
+			baseUrl: "https://api.githubcopilot.com",
+			headers: {
+				"User-Agent": "GitHubCopilotChat/0.35.0",
+				"Editor-Version": "vscode/1.105.1",
+				"Editor-Plugin-Version": "copilot-chat/0.35.0",
+				"Copilot-Integration-Id": "copilot-developer-cli",
+				"Openai-Intent": "conversation-edits",
+				"X-Initiator": "agent",
+			},
+			compat: { supportsStore: false, supportsDeveloperRole: false, supportsReasoningEffort: false },
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 0,
+				output: 0,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 128000,
+			maxTokens: 8192,
+		} satisfies Model<"openai-completions">,
+		"o1-mini": {
+			id: "o1-mini",
+			name: "o1-mini",
+			api: "openai-completions",
+			provider: "github-copilot",
+			baseUrl: "https://api.githubcopilot.com",
+			headers: {
+				"User-Agent": "GitHubCopilotChat/0.35.0",
+				"Editor-Version": "vscode/1.105.1",
+				"Editor-Plugin-Version": "copilot-chat/0.35.0",
+				"Copilot-Integration-Id": "copilot-developer-cli",
+				"Openai-Intent": "conversation-edits",
+				"X-Initiator": "agent",
+			},
+			compat: { supportsStore: false, supportsDeveloperRole: false, supportsReasoningEffort: false },
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 0,
+				output: 0,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 128000,
+			maxTokens: 8192,
+		} satisfies Model<"openai-completions">,
+	},
 } as const;

packages/ai/src/stream.ts

@@ -31,6 +31,10 @@ export function getApiKey(provider: any): string | undefined {
 	if (key) return key;
 
 	// Fall back to environment variables
+	if (provider === "github-copilot") {
+		return process.env.COPILOT_GITHUB_TOKEN || process.env.GH_TOKEN || process.env.GITHUB_TOKEN;
+	}
+
 	const envMap: Record<string, string> = {
 		openai: "OPENAI_API_KEY",
 		anthropic: "ANTHROPIC_API_KEY",

packages/ai/src/types.ts

@@ -30,6 +30,7 @@ export type KnownProvider =
 	| "anthropic"
 	| "google"
 	| "openai"
+	| "github-copilot"
 	| "xai"
 	| "groq"
 	| "cerebras"

packages/coding-agent/src/core/model-config.ts

@@ -3,8 +3,9 @@ import { type Static, Type } from "@sinclair/typebox";
 import AjvModule from "ajv";
 import { existsSync, readFileSync } from "fs";
 import { getModelsPath } from "../config.js";
+import { getGitHubCopilotBaseUrl, normalizeDomain, refreshGitHubCopilotToken } from "./oauth/github-copilot.js";
 import { getOAuthToken, type SupportedOAuthProvider } from "./oauth/index.js";
-import { loadOAuthCredentials } from "./oauth/storage.js";
+import { loadOAuthCredentials, saveOAuthCredentials } from "./oauth/storage.js";
 
 // Handle both default and named exports
 const Ajv = (AjvModule as any).default || AjvModule;
@@ -239,8 +240,23 @@ export function loadAndMergeModels(): { models: Model<Api>[]; error: string | nu
 		return { models: [], error };
 	}
 
-	// Merge: custom models come after built-in
+	const combined = [...builtInModels, ...customModels];
-	return { models: [...builtInModels, ...customModels], error: null };
+
+	const copilotCreds = loadOAuthCredentials("github-copilot");
+	if (copilotCreds?.enterpriseUrl) {
+		const domain = normalizeDomain(copilotCreds.enterpriseUrl);
+		if (domain) {
+			const baseUrl = getGitHubCopilotBaseUrl(domain);
+			return {
+				models: combined.map((m) =>
+					m.provider === "github-copilot" && m.baseUrl === "https://api.githubcopilot.com" ? { ...m, baseUrl } : m,
+				),
+				error: null,
+			};
+		}
+	}
+
+	return { models: combined, error: null };
 }
 
 /**
@@ -271,6 +287,26 @@ export async function getApiKeyForModel(model: Model<Api>): Promise<string | und
 		// 3. Fall back to ANTHROPIC_API_KEY env var
 	}
 
+	if (model.provider === "github-copilot") {
+		const oauthToken = await getOAuthToken("github-copilot");
+		if (oauthToken) {
+			return oauthToken;
+		}
+
+		const githubToken = process.env.COPILOT_GITHUB_TOKEN || process.env.GH_TOKEN || process.env.GITHUB_TOKEN;
+		if (!githubToken) {
+			return undefined;
+		}
+
+		const enterpriseDomain = process.env.COPILOT_ENTERPRISE_URL
+			? normalizeDomain(process.env.COPILOT_ENTERPRISE_URL)
+			: undefined;
+
+		const creds = await refreshGitHubCopilotToken(githubToken, enterpriseDomain || undefined);
+		saveOAuthCredentials("github-copilot", creds);
+		return creds.access;
+	}
+
 	// For built-in providers, use getApiKey from @mariozechner/pi-ai
 	return getApiKey(model.provider as KnownProvider);
 }
@@ -287,7 +323,18 @@ export async function getAvailableModels(): Promise<{ models: Model<Api>[]; erro
 	}
 
 	const availableModels: Model<Api>[] = [];
+	const copilotCreds = loadOAuthCredentials("github-copilot");
+	const hasCopilotEnv = !!(process.env.COPILOT_GITHUB_TOKEN || process.env.GH_TOKEN || process.env.GITHUB_TOKEN);
+	const hasCopilot = !!copilotCreds || hasCopilotEnv;
+
 	for (const model of allModels) {
+		if (model.provider === "github-copilot") {
+			if (hasCopilot) {
+				availableModels.push(model);
+			}
+			continue;
+		}
+
 		const apiKey = await getApiKeyForModel(model);
 		if (apiKey) {
 			availableModels.push(model);
@@ -318,7 +365,7 @@ export function findModel(provider: string, modelId: string): { model: Model<Api
  */
 const providerToOAuthProvider: Record<string, SupportedOAuthProvider> = {
 	anthropic: "anthropic",
-	// Add more mappings as OAuth support is added for other providers
+	"github-copilot": "github-copilot",
 };
 
 // Cache for OAuth status per provider (avoids file reads on every render)

packages/coding-agent/src/core/model-resolver.ts

@@ -14,6 +14,7 @@ export const defaultModelPerProvider: Record<KnownProvider, string> = {
 	anthropic: "claude-sonnet-4-5",
 	openai: "gpt-5.1-codex",
 	google: "gemini-2.5-pro",
+	"github-copilot": "gpt-4o",
 	openrouter: "openai/gpt-5.1-codex",
 	xai: "grok-4-fast-non-reasoning",
 	groq: "openai/gpt-oss-120b",

packages/coding-agent/src/core/oauth/github-copilot.ts

@@ -0,0 +1,235 @@
+import type { OAuthCredentials } from "./storage.js";
+
+const CLIENT_ID = "Iv1.b507a08c87ecfe98";
+
+const COPILOT_HEADERS = {
+	"User-Agent": "GitHubCopilotChat/0.35.0",
+	"Editor-Version": "vscode/1.105.1",
+	"Editor-Plugin-Version": "copilot-chat/0.35.0",
+	"Copilot-Integration-Id": "copilot-developer-cli",
+	"Openai-Intent": "conversation-edits",
+	"X-Initiator": "agent",
+} as const;
+
+type DeviceCodeResponse = {
+	device_code: string;
+	user_code: string;
+	verification_uri: string;
+	interval: number;
+	expires_in: number;
+};
+
+type DeviceTokenSuccessResponse = {
+	access_token: string;
+	token_type?: string;
+	scope?: string;
+};
+
+type DeviceTokenErrorResponse = {
+	error: string;
+	error_description?: string;
+	interval?: number;
+};
+
+export function normalizeDomain(input: string): string | null {
+	const trimmed = input.trim();
+	if (!trimmed) return null;
+	try {
+		const url = trimmed.includes("://") ? new URL(trimmed) : new URL(`https://${trimmed}`);
+		return url.hostname;
+	} catch {
+		return null;
+	}
+}
+
+function getUrls(domain: string): {
+	deviceCodeUrl: string;
+	accessTokenUrl: string;
+	copilotTokenUrl: string;
+} {
+	return {
+		deviceCodeUrl: `https://${domain}/login/device/code`,
+		accessTokenUrl: `https://${domain}/login/oauth/access_token`,
+		copilotTokenUrl: `https://api.${domain}/copilot_internal/v2/token`,
+	};
+}
+
+export function getGitHubCopilotBaseUrl(enterpriseDomain?: string): string {
+	if (!enterpriseDomain) return "https://api.githubcopilot.com";
+	return `https://copilot-api.${enterpriseDomain}`;
+}
+
+async function fetchJson(url: string, init: RequestInit): Promise<unknown> {
+	const response = await fetch(url, init);
+	if (!response.ok) {
+		const text = await response.text();
+		throw new Error(`${response.status} ${response.statusText}: ${text}`);
+	}
+	return response.json();
+}
+
+async function startDeviceFlow(domain: string): Promise<DeviceCodeResponse> {
+	const urls = getUrls(domain);
+	const data = await fetchJson(urls.deviceCodeUrl, {
+		method: "POST",
+		headers: {
+			Accept: "application/json",
+			"Content-Type": "application/json",
+			"User-Agent": "GitHubCopilotChat/0.35.0",
+		},
+		body: JSON.stringify({
+			client_id: CLIENT_ID,
+			scope: "read:user",
+		}),
+	});
+
+	if (!data || typeof data !== "object") {
+		throw new Error("Invalid device code response");
+	}
+
+	const deviceCode = (data as Record<string, unknown>).device_code;
+	const userCode = (data as Record<string, unknown>).user_code;
+	const verificationUri = (data as Record<string, unknown>).verification_uri;
+	const interval = (data as Record<string, unknown>).interval;
+	const expiresIn = (data as Record<string, unknown>).expires_in;
+
+	if (
+		typeof deviceCode !== "string" ||
+		typeof userCode !== "string" ||
+		typeof verificationUri !== "string" ||
+		typeof interval !== "number" ||
+		typeof expiresIn !== "number"
+	) {
+		throw new Error("Invalid device code response fields");
+	}
+
+	return {
+		device_code: deviceCode,
+		user_code: userCode,
+		verification_uri: verificationUri,
+		interval,
+		expires_in: expiresIn,
+	};
+}
+
+async function pollForGitHubAccessToken(
+	domain: string,
+	deviceCode: string,
+	intervalSeconds: number,
+	expiresIn: number,
+) {
+	const urls = getUrls(domain);
+	const deadline = Date.now() + expiresIn * 1000;
+	let intervalMs = Math.max(1000, Math.floor(intervalSeconds * 1000));
+
+	while (Date.now() < deadline) {
+		const raw = await fetchJson(urls.accessTokenUrl, {
+			method: "POST",
+			headers: {
+				Accept: "application/json",
+				"Content-Type": "application/json",
+				"User-Agent": "GitHubCopilotChat/0.35.0",
+			},
+			body: JSON.stringify({
+				client_id: CLIENT_ID,
+				device_code: deviceCode,
+				grant_type: "urn:ietf:params:oauth:grant-type:device_code",
+			}),
+		});
+
+		if (raw && typeof raw === "object" && typeof (raw as DeviceTokenSuccessResponse).access_token === "string") {
+			return (raw as DeviceTokenSuccessResponse).access_token;
+		}
+
+		if (raw && typeof raw === "object" && typeof (raw as DeviceTokenErrorResponse).error === "string") {
+			const err = (raw as DeviceTokenErrorResponse).error;
+			if (err === "authorization_pending") {
+				await new Promise((resolve) => setTimeout(resolve, intervalMs));
+				continue;
+			}
+
+			if (err === "slow_down") {
+				intervalMs += 5000;
+				await new Promise((resolve) => setTimeout(resolve, intervalMs));
+				continue;
+			}
+
+			throw new Error(`Device flow failed: ${err}`);
+		}
+
+		await new Promise((resolve) => setTimeout(resolve, intervalMs));
+	}
+
+	throw new Error("Device flow timed out");
+}
+
+export async function refreshGitHubCopilotToken(
+	refreshToken: string,
+	enterpriseDomain?: string,
+): Promise<OAuthCredentials> {
+	const domain = enterpriseDomain || "github.com";
+	const urls = getUrls(domain);
+	const raw = await fetchJson(urls.copilotTokenUrl, {
+		headers: {
+			Accept: "application/json",
+			Authorization: `Bearer ${refreshToken}`,
+			...COPILOT_HEADERS,
+		},
+	});
+
+	if (!raw || typeof raw !== "object") {
+		throw new Error("Invalid Copilot token response");
+	}
+
+	const token = (raw as Record<string, unknown>).token;
+	const expiresAt = (raw as Record<string, unknown>).expires_at;
+
+	if (typeof token !== "string" || typeof expiresAt !== "number") {
+		throw new Error("Invalid Copilot token response fields");
+	}
+
+	const expires = expiresAt * 1000 - 5 * 60 * 1000;
+	return {
+		type: "oauth",
+		refresh: refreshToken,
+		access: token,
+		expires,
+		enterpriseUrl: enterpriseDomain,
+	} satisfies OAuthCredentials;
+}
+
+export async function loginGitHubCopilot(options: {
+	onAuth: (url: string, instructions?: string) => void;
+	onPrompt: (prompt: { message: string; placeholder?: string; allowEmpty?: boolean }) => Promise<string>;
+}): Promise<OAuthCredentials> {
+	const input = await options.onPrompt({
+		message: "GitHub Enterprise URL/domain (blank for github.com)",
+		placeholder: "company.ghe.com",
+		allowEmpty: true,
+	});
+
+	const trimmed = input.trim();
+	const enterpriseDomain = normalizeDomain(input);
+	if (trimmed && !enterpriseDomain) {
+		throw new Error("Invalid GitHub Enterprise URL/domain");
+	}
+	const domain = enterpriseDomain || "github.com";
+
+	const device = await startDeviceFlow(domain);
+	options.onAuth(device.verification_uri, `Enter code: ${device.user_code}`);
+
+	const githubAccessToken = await pollForGitHubAccessToken(
+		domain,
+		device.device_code,
+		device.interval,
+		device.expires_in,
+	);
+	return await refreshGitHubCopilotToken(githubAccessToken, enterpriseDomain ?? undefined);
+}
+
+export async function exchangeGitHubTokenForCopilotCredentials(options: {
+	githubToken: string;
+	enterpriseDomain?: string;
+}): Promise<OAuthCredentials> {
+	return refreshGitHubCopilotToken(options.githubToken, options.enterpriseDomain);
+}

packages/coding-agent/src/core/oauth/index.ts

@@ -1,4 +1,5 @@
 import { loginAnthropic, refreshAnthropicToken } from "./anthropic.js";
+import { loginGitHubCopilot, refreshGitHubCopilotToken } from "./github-copilot.js";
 import {
 	listOAuthProviders as listOAuthProvidersFromStorage,
 	loadOAuthCredentials,
@@ -18,6 +19,17 @@ export interface OAuthProviderInfo {
 	available: boolean;
 }
 
+export type OAuthPrompt = {
+	message: string;
+	placeholder?: string;
+	allowEmpty?: boolean;
+};
+
+export type OAuthAuthInfo = {
+	url: string;
+	instructions?: string;
+};
+
 /**
  * Get list of OAuth providers
  */
@@ -30,8 +42,8 @@ export function getOAuthProviders(): OAuthProviderInfo[] {
 		},
 		{
 			id: "github-copilot",
-			name: "GitHub Copilot (coming soon)",
+			name: "GitHub Copilot",
-			available: false,
+			available: true,
 		},
 	];
 }
@@ -41,15 +53,24 @@ export function getOAuthProviders(): OAuthProviderInfo[] {
  */
 export async function login(
 	provider: SupportedOAuthProvider,
-	onAuthUrl: (url: string) => void,
+	onAuth: (info: OAuthAuthInfo) => void,
-	onPromptCode: () => Promise<string>,
+	onPrompt: (prompt: OAuthPrompt) => Promise<string>,
 ): Promise<void> {
 	switch (provider) {
 		case "anthropic":
-			await loginAnthropic(onAuthUrl, onPromptCode);
+			await loginAnthropic(
+				(url) => onAuth({ url }),
+				async () => onPrompt({ message: "Paste the authorization code below:" }),
+			);
 			break;
-		case "github-copilot":
+		case "github-copilot": {
-			throw new Error("GitHub Copilot OAuth is not yet implemented");
+			const creds = await loginGitHubCopilot({
+				onAuth: (url, instructions) => onAuth({ url, instructions }),
+				onPrompt,
+			});
+			saveOAuthCredentials("github-copilot", creds);
+			break;
+		}
 		default:
 			throw new Error(`Unknown OAuth provider: ${provider}`);
 	}
@@ -78,7 +99,8 @@ export async function refreshToken(provider: SupportedOAuthProvider): Promise<st
 			newCredentials = await refreshAnthropicToken(credentials.refresh);
 			break;
 		case "github-copilot":
-			throw new Error("GitHub Copilot OAuth is not yet implemented");
+			newCredentials = await refreshGitHubCopilotToken(credentials.refresh, credentials.enterpriseUrl);
+			break;
 		default:
 			throw new Error(`Unknown OAuth provider: ${provider}`);
 	}

packages/coding-agent/src/core/oauth/storage.ts

@@ -6,6 +6,7 @@ export interface OAuthCredentials {
 	refresh: string;
 	access: string;
 	expires: number;
+	enterpriseUrl?: string;
 }
 
 interface OAuthStorageFormat {

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -1378,14 +1378,14 @@ export class InteractiveMode {
 						try {
 							await login(
 								providerId as SupportedOAuthProvider,
-								(url: string) => {
+								(info) => {
 									this.chatContainer.addChild(new Spacer(1));
 									this.chatContainer.addChild(new Text(theme.fg("accent", "Opening browser to:"), 1, 0));
-									this.chatContainer.addChild(new Text(theme.fg("accent", url), 1, 0));
+									this.chatContainer.addChild(new Text(theme.fg("accent", info.url), 1, 0));
-									this.chatContainer.addChild(new Spacer(1));
+									if (info.instructions) {
-									this.chatContainer.addChild(
+										this.chatContainer.addChild(new Spacer(1));
-										new Text(theme.fg("warning", "Paste the authorization code below:"), 1, 0),
+										this.chatContainer.addChild(new Text(theme.fg("warning", info.instructions), 1, 0));
-									);
+									}
 									this.ui.requestRender();
 
 									const openCmd =
@@ -1394,9 +1394,16 @@ export class InteractiveMode {
 											: process.platform === "win32"
 												? "start"
 												: "xdg-open";
-									exec(`${openCmd} "${url}"`);
+									exec(`${openCmd} "${info.url}"`);
 								},
-								async () => {
+								async (prompt) => {
+									this.chatContainer.addChild(new Spacer(1));
+									this.chatContainer.addChild(new Text(theme.fg("warning", prompt.message), 1, 0));
+									if (prompt.placeholder) {
+										this.chatContainer.addChild(new Text(theme.fg("dim", prompt.placeholder), 1, 0));
+									}
+									this.ui.requestRender();
+
 									return new Promise<string>((resolve) => {
 										const codeInput = new Input();
 										codeInput.onSubmit = () => {