Add copilot-relay usage: Copilot plan and quota

README.md

@@ -62,6 +62,9 @@ copilot-relay cache --hourly         # or --daily; narrow with --since 6h or --m
 copilot-relay cache --json
 ```
 
+Check your Copilot plan and quota with `copilot-relay usage`; add `--json` for
+scripts. It asks GitHub directly with the stored token, so no relay needs to run.
+
 ## Go further
 
 **[Open the Wiki](https://github.com/D0n9X1n/copilot-relay/wiki)** · **[English / 中文](wiki/README.md)**

src/lib/auth.ts

@@ -73,6 +73,27 @@ const readGitHubToken = async () => {
   return token.trim()
 }
 
+// The stored token, or undefined when there is none, for a command that must not write. Unlike
+// readGitHubToken it creates no directory or file and migrates no legacy token.
+export const readStoredGitHubToken = async (): Promise<string | undefined> => {
+  let content: string
+
+  try {
+    content = await fs.readFile(paths.githubTokenPath, "utf8")
+  } catch (error) {
+    if ((error as NodeJS.ErrnoException).code === "ENOENT") {
+      return undefined
+    }
+
+    throw error
+  }
+
+  const token = content.trim()
+  registerLogSecret(token)
+
+  return token === "" ? undefined : token
+}
+
 const writeGitHubToken = async (token: string) => {
   registerLogSecret(token.trim())
   await ensurePaths()
@@ -256,6 +277,25 @@ const getCopilotToken = async (
   return (await response.json()) as CopilotTokenResponse
 }
 
+// The plan and quota behind `copilot-relay usage`. It is read with the GitHub token itself, so no
+// Copilot token is exchanged for it. The body is GitHub's internal format; the caller checks it.
+export const getCopilotUsage = async (
+  githubToken: string,
+  vsCodeVersion: string,
+  signal?: AbortSignal,
+): Promise<unknown> => {
+  const response = await fetch(`${githubApiBaseUrl}/copilot_internal/user`, {
+    headers: githubHeaders(githubToken, vsCodeVersion),
+    signal,
+  })
+
+  if (!response.ok) {
+    throw new HTTPError("Failed to get Copilot usage", response)
+  }
+
+  return response.json()
+}
+
 const isCopilotTokenError = (error: unknown): boolean =>
   error instanceof HTTPError && error.message === "Failed to get Copilot token"
 

src/lib/config.ts

@@ -3,7 +3,7 @@ import type { AppConfig } from "~/lib/app-config"
 import type { CopilotModelCatalog } from "~/copilot/models"
 import type { RequestTrace } from "./request-trace"
 
-const vscodeVersion = "1.99.3"
+export const vscodeVersion = "1.99.3"
 
 export interface ProxyConfig {
   host: string