fix: use dynamic Copilot API endpoint from token response

- Read endpoints.api from /copilot_internal/v2/token response and store
  in state.copilotApiBaseUrl; individual accounts should use
  https://api.individual.githubcopilot.com (not the hardcoded
  https://api.githubcopilot.com) which is why Claude models were missing

- Refresh copilotApiBaseUrl on token refresh cycles

- Replace narrow claude-sonnet/opus hardcoded normalization with a
  comprehensive 5-pattern normalizeClaude() that handles all versioned
  Claude model IDs sent by Claude Code (haiku-4-5, sonnet-4/4.5/4.6,
  opus-4/4.5/4.6, legacy claude-3-x-family formats)

Author: dray

src/lib/api-config.ts

@@ -14,9 +14,10 @@ const USER_AGENT = `GitHubCopilotChat/${COPILOT_VERSION}`
 const API_VERSION = "2025-04-01"
 
 export const copilotBaseUrl = (state: State) =>
-  state.accountType === "individual" ?
+  state.copilotApiBaseUrl ??
+  (state.accountType === "individual" ?
     "https://api.githubcopilot.com"
-  : `https://api.${state.accountType}.githubcopilot.com`
+  : `https://api.${state.accountType}.githubcopilot.com`)
 export const copilotHeaders = (state: State, vision: boolean = false) => {
   const headers: Record<string, string> = {
     Authorization: `Bearer ${state.copilotToken}`,

src/lib/state.ts

@@ -5,6 +5,7 @@ export interface State {
   copilotToken?: string
 
   accountType: string
+  copilotApiBaseUrl?: string
   models?: ModelsResponse
   vsCodeVersion?: string
 

src/lib/token.ts

@@ -16,8 +16,11 @@ const writeGithubToken = (token: string) =>
   fs.writeFile(PATHS.GITHUB_TOKEN_PATH, token)
 
 export const setupCopilotToken = async () => {
-  const { token, refresh_in } = await getCopilotToken()
+  const { token, refresh_in, endpoints } = await getCopilotToken()
   state.copilotToken = token
+  if (endpoints?.api) {
+    state.copilotApiBaseUrl = endpoints.api
+  }
 
   // Display the Copilot token to the screen
   consola.debug("GitHub Copilot Token fetched successfully!")
@@ -29,8 +32,11 @@ export const setupCopilotToken = async () => {
   setInterval(async () => {
     consola.debug("Refreshing Copilot token")
     try {
-      const { token } = await getCopilotToken()
+      const { token, endpoints } = await getCopilotToken()
       state.copilotToken = token
+      if (endpoints?.api) {
+        state.copilotApiBaseUrl = endpoints.api
+      }
       consola.debug("Copilot token refreshed")
       if (state.showToken) {
         consola.info("Refreshed Copilot token:", token)

src/routes/messages/non-stream-translation.ts

@@ -47,13 +47,39 @@ export function translateToOpenAI(
 }
 
 function translateModelName(model: string): string {
-  // Subagent requests use a specific model number which Copilot doesn't support
-  if (model.startsWith("claude-sonnet-4-")) {
-    return model.replace(/^claude-sonnet-4-.*/, "claude-sonnet-4")
-  } else if (model.startsWith("claude-opus-")) {
-    return model.replace(/^claude-opus-4-.*/, "claude-opus-4")
-  }
-  return model
+  // Normalize Claude model IDs to the base format Copilot accepts.
+  // Claude Code sends versioned IDs (e.g. claude-sonnet-4-20250514, claude-haiku-4-5-20251001)
+  // but Copilot only recognizes the base form (claude-sonnet-4, claude-haiku-4-5).
+  const normalized = normalizeClaude(model)
+  return normalized ?? model
+}
+
+function normalizeClaude(model: string): string | undefined {
+  const lower = model.toLowerCase()
+  // Strip 8-digit date suffix (e.g. -20250514)
+  const base = lower.replace(/-\d{8}$/, "")
+
+  // Pattern 1: claude-{family}-{major}-{minor} → e.g. claude-haiku-4-5, claude-opus-4-5
+  const p1 = base.match(/^claude-([a-z]+)-(\d+)-(\d+)$/)
+  if (p1) return `claude-${p1[1]}-${p1[2]}.${p1[3]}`
+
+  // Pattern 2: claude-{major}-{minor}-{family} → e.g. claude-3-5-sonnet, claude-3-5-haiku
+  const p2 = base.match(/^claude-(\d+)-(\d+)-([a-z]+)$/)
+  if (p2) return `claude-${p2[3]}-${p2[1]}.${p2[2]}`
+
+  // Pattern 3: claude-{family}-{major}.{minor} → e.g. claude-haiku-4.5 (already normalized)
+  const p3 = base.match(/^claude-([a-z]+)-(\d+)\.(\d+)$/)
+  if (p3) return `claude-${p3[1]}-${p3[2]}.${p3[3]}`
+
+  // Pattern 4: claude-{family}-{major} → e.g. claude-sonnet-4, claude-opus-4
+  const p4 = base.match(/^claude-([a-z]+)-(\d+)$/)
+  if (p4) return `claude-${p4[1]}-${p4[2]}`
+
+  // Pattern 5: claude-{major}-{family} → e.g. claude-3-opus
+  const p5 = base.match(/^claude-(\d+)-([a-z]+)$/)
+  if (p5) return `claude-${p5[2]}-${p5[1]}`
+
+  return undefined
 }
 
 function translateAnthropicMessagesToOpenAI(

src/services/github/get-copilot-token.ts

@@ -20,4 +20,7 @@ interface GetCopilotTokenResponse {
   expires_at: number
   refresh_in: number
   token: string
+  endpoints?: {
+    api?: string
+  }
 }