diff --git a/CHANGELOG.md b/CHANGELOG.md
index a8080e5f48..7389b860f8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ This is the log of notable changes to EAS CLI and related packages.
 
 ### 🎉 New features
 
+- [eas-cli] Add `code` to the `--json` error: `EAS_PROJECT_NOT_CONFIGURED` when the project is not linked to EAS, and `EAS_LOGIN_REQUIRED` when a non-interactive run is not logged in. ([#4594](https://github.com/expo/eas-cli/pull/4594) by [@vonovak](https://github.com/vonovak))
 - [eas-cli] Print `{"error": {"message", "requestId"?}}` on stdout when a command run with `--json` fails, and keep all other output off stdout from the start of the command. ([#4593](https://github.com/expo/eas-cli/pull/4593) by [@vonovak](https://github.com/vonovak))
 - [build-tools] Let the MCP server read text and image files from sandboxes. ([#4555](https://github.com/expo/eas-cli/pull/4555) by [@AHGIJMKLKKZNPJKQR](https://github.com/AHGIJMKLKKZNPJKQR))
 
diff --git a/packages/eas-cli/src/commandUtils/EasCommand.ts b/packages/eas-cli/src/commandUtils/EasCommand.ts
index becadd3e48..ad2e424bb6 100644
--- a/packages/eas-cli/src/commandUtils/EasCommand.ts
+++ b/packages/eas-cli/src/commandUtils/EasCommand.ts
@@ -278,13 +278,16 @@ export default abstract class EasCommand extends Command {
     const commandId = this.id ?? 'unknown';
     let baseMessage = `${commandId} command failed.`;
     let message = err.message;
+    let code: string | undefined;
     let requestId: string | undefined;
     if (err instanceof Errors.ExitError) {
       // Errors.exit(1) carries no reason; the code that called it printed the reason already.
       Log.errorToStderr(err.message);
       message = baseMessage;
-    } else if (err instanceof EasCommandError) {
+    } else if (err instanceof EasCommandError || err instanceof Errors.CLIError) {
       Log.errorToStderr(err.message);
+      // Only codes that eas-cli sets. GraphQL error codes belong to the server and stay out.
+      code = err.code;
     } else if (err instanceof CombinedError && err?.graphQLErrors) {
       const cleanGQLErrorsMessage = err?.graphQLErrors
         .map((graphQLError: GraphQLError) => {
@@ -329,7 +332,7 @@ export default abstract class EasCommand extends Command {
       Log.errorToStderr(err.message);
     }
     if (this.jsonOutputRequested()) {
-      printJsonErrorOutput({ message, requestId });
+      printJsonErrorOutput({ message, code, requestId });
     }
     Log.debug(err);
     Sentry.withScope(scope => {
diff --git a/packages/eas-cli/src/commandUtils/__tests__/EasCommand-test.ts b/packages/eas-cli/src/commandUtils/__tests__/EasCommand-test.ts
index 20b0447fc0..47db92f6fb 100644
--- a/packages/eas-cli/src/commandUtils/__tests__/EasCommand-test.ts
+++ b/packages/eas-cli/src/commandUtils/__tests__/EasCommand-test.ts
@@ -344,10 +344,43 @@ describe('EasCommand', () => {
 
           expect(printJsonErrorOutput).toHaveBeenCalledWith({
             message: 'EAS project not configured.',
+            code: undefined,
             requestId: undefined,
           });
         });
 
+        it('prints the code of an EasCommandError', async () => {
+          const TestEasCommand = createJsonTestEasCommand();
+          const { printJsonErrorOutput } = jest.requireMock('../../utils/json');
+          const { EasCommandError } = require('../errors');
+          jest.spyOn(TestEasCommand.prototype, 'runAsync').mockImplementation(() => {
+            throw new EasCommandError('EAS project not configured.', {
+              code: 'EAS_PROJECT_NOT_CONFIGURED',
+            });
+          });
+
+          await expect(TestEasCommand.run(['--json'], mockConfig)).rejects.toThrow();
+
+          expect(printJsonErrorOutput).toHaveBeenCalledWith(
+            expect.objectContaining({ code: 'EAS_PROJECT_NOT_CONFIGURED' })
+          );
+        });
+
+        it('prints the code of an oclif error', async () => {
+          const TestEasCommand = createJsonTestEasCommand();
+          const { printJsonErrorOutput } = jest.requireMock('../../utils/json');
+          const { Errors } = require('@oclif/core');
+          jest.spyOn(TestEasCommand.prototype, 'runAsync').mockImplementation(() => {
+            Errors.error('Log in first.', { code: 'EAS_LOGIN_REQUIRED' });
+          });
+
+          await expect(TestEasCommand.run(['--json'], mockConfig)).rejects.toThrow();
+
+          expect(printJsonErrorOutput).toHaveBeenCalledWith(
+            expect.objectContaining({ message: 'Log in first.', code: 'EAS_LOGIN_REQUIRED' })
+          );
+        });
+
         it('prints the command failure, not EEXIT, for Errors.exit', async () => {
           const TestEasCommand = createJsonTestEasCommand();
           const { printJsonErrorOutput } = jest.requireMock('../../utils/json');
@@ -360,6 +393,7 @@ describe('EasCommand', () => {
 
           expect(printJsonErrorOutput).toHaveBeenCalledWith({
             message: `${TestEasCommand.id} command failed.`,
+            code: undefined,
             requestId: undefined,
           });
         });
@@ -385,7 +419,7 @@ describe('EasCommand', () => {
           expect(printJsonErrorOutput).toHaveBeenCalledWith(
             expect.objectContaining({ requestId: mockRequestId })
           );
-          expect(printJsonErrorOutput.mock.calls[0][0]).not.toHaveProperty('code');
+          expect(printJsonErrorOutput.mock.calls[0][0].code).toBeUndefined();
         });
 
         it.each([
diff --git a/packages/eas-cli/src/commandUtils/context/contextUtils/__tests__/getProjectIdAsync-test.ts b/packages/eas-cli/src/commandUtils/context/contextUtils/__tests__/getProjectIdAsync-test.ts
index b7f724a3b0..38f8f0204d 100644
--- a/packages/eas-cli/src/commandUtils/context/contextUtils/__tests__/getProjectIdAsync-test.ts
+++ b/packages/eas-cli/src/commandUtils/context/contextUtils/__tests__/getProjectIdAsync-test.ts
@@ -506,6 +506,16 @@ describe(getProjectIdAsync, () => {
       expect(fetchOrCreateProjectIDForWriteToConfigWithConfirmationAsync).not.toHaveBeenCalled();
     });
 
+    it('gives the non-interactive error the EAS_PROJECT_NOT_CONFIGURED code', async () => {
+      await expect(
+        getProjectIdAsync(
+          sessionManager,
+          { sdkVersion: '52.0.0', name: 'test', slug: 'test' },
+          { nonInteractive: true }
+        )
+      ).rejects.toMatchObject({ code: 'EAS_PROJECT_NOT_CONFIGURED' });
+    });
+
     it('defers to the project fetch in non-interactive mode when the account is already known', async () => {
       const sessionManagerMock = mock<SessionManager>();
       when(sessionManagerMock.ensureLoggedInAsync(anything())).thenResolve({
diff --git a/packages/eas-cli/src/commandUtils/errors.ts b/packages/eas-cli/src/commandUtils/errors.ts
index 43186a3f33..338ef7fdc6 100644
--- a/packages/eas-cli/src/commandUtils/errors.ts
+++ b/packages/eas-cli/src/commandUtils/errors.ts
@@ -1,7 +1,9 @@
 export class EasCommandError extends Error {
-  // constructor is not useless, since the constructor for Error allows for optional `message`
-  // eslint-disable-next-line @typescript-eslint/no-useless-constructor
-  constructor(message: string) {
+  /** A stable identifier, printed in the `--json` error output so programs need not match the message. */
+  public readonly code?: string;
+
+  constructor(message: string, { code }: { code?: string } = {}) {
     super(message);
+    this.code = code;
   }
 }
diff --git a/packages/eas-cli/src/commandUtils/flags.ts b/packages/eas-cli/src/commandUtils/flags.ts
index 3158ef7326..9f18cdd906 100644
--- a/packages/eas-cli/src/commandUtils/flags.ts
+++ b/packages/eas-cli/src/commandUtils/flags.ts
@@ -8,7 +8,7 @@ export function isNonInteractiveByDefault(): boolean {
 export const EasNonInteractiveAndJsonFlags = {
   json: Flags.boolean({
     description:
-      'Enable JSON output, non-JSON messages will be printed to stderr. On failure, prints {"error": {"message", "requestId"?}}. Implies --non-interactive.',
+      'Enable JSON output, non-JSON messages will be printed to stderr. On failure, prints {"error": {"message", "code"?, "requestId"?}}. Implies --non-interactive.',
   }),
   'non-interactive': Flags.boolean({
     description: 'Run the command in non-interactive mode.',
@@ -88,7 +88,7 @@ export const EASNonInteractiveFlag = {
 export const EasJsonOnlyFlag = {
   json: Flags.boolean({
     description:
-      'Enable JSON output, non-JSON messages will be printed to stderr. On failure, prints {"error": {"message", "requestId"?}}.',
+      'Enable JSON output, non-JSON messages will be printed to stderr. On failure, prints {"error": {"message", "code"?, "requestId"?}}.',
   }),
 };
 
diff --git a/packages/eas-cli/src/project/projectNotConfiguredError.ts b/packages/eas-cli/src/project/projectNotConfiguredError.ts
index 4f475cef99..66d63409c4 100644
--- a/packages/eas-cli/src/project/projectNotConfiguredError.ts
+++ b/packages/eas-cli/src/project/projectNotConfiguredError.ts
@@ -1,3 +1,4 @@
+import { EasCommandError } from '../commandUtils/errors';
 import { Actor, getCreatableAccountNames } from '../user/User';
 
 /**
@@ -20,8 +21,8 @@ export function getUnconfiguredProjectError({
   accountName?: string;
   reason?: string;
   additionalFix?: string;
-}): Error {
-  return new Error(
+}): EasCommandError {
+  return new EasCommandError(
     `EAS project not configured. ${reason} ` +
       `Run one of the following, then re-run this command:\n\n` +
       `To link an existing project:\n\n` +
@@ -29,6 +30,7 @@ export function getUnconfiguredProjectError({
       `To create a new project:\n\n` +
       `  eas init --account ${accountName ?? '<account-name>'} --non-interactive\n\n` +
       `Accounts you can create projects in: ${getCreatableAccountNames(actor).join(', ')}` +
-      (additionalFix ? `\n\n${additionalFix}` : '')
+      (additionalFix ? `\n\n${additionalFix}` : ''),
+    { code: 'EAS_PROJECT_NOT_CONFIGURED' }
   );
 }
diff --git a/packages/eas-cli/src/user/SessionManager.ts b/packages/eas-cli/src/user/SessionManager.ts
index 43ff17e53d..834810bf1f 100644
--- a/packages/eas-cli/src/user/SessionManager.ts
+++ b/packages/eas-cli/src/user/SessionManager.ts
@@ -156,7 +156,8 @@ export default class SessionManager {
         )} environment variable if you're using EAS CLI on CI (${learnMore(
           'https://docs.expo.dev/accounts/programmatic-access/',
           { dim: false }
-        )})`
+        )})`,
+        { code: 'EAS_LOGIN_REQUIRED' }
       );
     }
     if (printNewLine) {
diff --git a/packages/eas-cli/src/user/__tests__/SessionManager-test.ts b/packages/eas-cli/src/user/__tests__/SessionManager-test.ts
index 5840df0f79..4a8b337661 100644
--- a/packages/eas-cli/src/user/__tests__/SessionManager-test.ts
+++ b/packages/eas-cli/src/user/__tests__/SessionManager-test.ts
@@ -254,6 +254,15 @@ describe(SessionManager, () => {
   });
 
   describe('showLoginPromptAsync', () => {
+    it('fails with the EAS_LOGIN_REQUIRED code in non-interactive mode', async () => {
+      const sessionManager = new SessionManager(analytics);
+
+      await expect(
+        sessionManager.showLoginPromptAsync({ nonInteractive: true })
+      ).rejects.toMatchObject({ code: 'EAS_LOGIN_REQUIRED' });
+      expect(promptAsync).not.toHaveBeenCalled();
+    });
+
     it('prompts for OTP when 2FA is enabled', async () => {
       jest
         .mocked(promptAsync)
diff --git a/packages/eas-cli/src/utils/json.ts b/packages/eas-cli/src/utils/json.ts
index 5a438326d1..33425ce456 100644
--- a/packages/eas-cli/src/utils/json.ts
+++ b/packages/eas-cli/src/utils/json.ts
@@ -25,13 +25,14 @@ export function printJsonOnlyOutput(value: object): void {
 
 export interface JsonErrorOutput {
   message: string;
+  code?: string;
   requestId?: string;
 }
 
 let jsonErrorPrinted = false;
 
 /**
- * Print `{ "error": { message, requestId? } }` on stdout for a command that failed with --json.
+ * Print `{ "error": { message, code?, requestId? } }` on stdout for a command that failed with --json.
  *
  * Once per process: `update:rollback` runs other commands in-process, and the innermost error is the one
  * that says what went wrong.