diff --git a/src/main/hosted-sandbox/dev-token-claims-probe.test.ts b/src/main/hosted-sandbox/dev-token-claims-probe.test.ts
new file mode 100644
index 00000000000..bec3e60c296
--- /dev/null
+++ b/src/main/hosted-sandbox/dev-token-claims-probe.test.ts
@@ -0,0 +1,31 @@
+import { afterEach, describe, expect, it } from 'vitest'
+import { installDevTokenClaimsProbe, tokenOrgClaims } from './dev-token-claims-probe'
+
+const encode = (value: unknown): string => Buffer.from(JSON.stringify(value)).toString('base64url')
+const jwt = (claims: unknown): string => `${encode({ alg: 'ES256' })}.${encode(claims)}.sig`
+
+describe('dev token claims probe (GH-LIST-MISSING)', () => {
+  afterEach(() => {
+    Reflect.deleteProperty(globalThis, '__orcaCloudTokenClaims')
+  })
+
+  it('reads only org, role and user from the payload', () => {
+    expect(tokenOrgClaims(jwt({ sub: 'u1', org: 'o1', org_role: 'owner', exp: 1 }))).toEqual({
+      org: 'o1',
+      orgRole: 'owner',
+      sub: 'u1'
+    })
+    expect(tokenOrgClaims(jwt({ sub: 'u1' }))).toEqual({ org: null, orgRole: null, sub: 'u1' })
+    expect(tokenOrgClaims('not-a-token')).toEqual({ org: null, orgRole: null, sub: null })
+  })
+
+  it('exists only in dev builds, and never hands back the token', async () => {
+    expect(installDevTokenClaimsProbe(async () => jwt({ sub: 'u1', org: 'o1' }), true)).toBeNull()
+    expect('__orcaCloudTokenClaims' in globalThis).toBe(false)
+    const probe = installDevTokenClaimsProbe(async () => jwt({ sub: 'u1', org: 'o1' }), false)
+    expect('__orcaCloudTokenClaims' in globalThis).toBe(true)
+    const answer = await probe?.()
+    expect(answer).toEqual({ org: 'o1', orgRole: null, sub: 'u1' })
+    expect(JSON.stringify(answer)).not.toContain('sig')
+  })
+})
diff --git a/src/main/hosted-sandbox/dev-token-claims-probe.ts b/src/main/hosted-sandbox/dev-token-claims-probe.ts
new file mode 100644
index 00000000000..a665fb8bb20
--- /dev/null
+++ b/src/main/hosted-sandbox/dev-token-claims-probe.ts
@@ -0,0 +1,37 @@
+// GH-LIST-MISSING diagnostics, dev builds only: which org the Orca Cloud token in use claims, next
+// to the team the app shows. A token minted for another team (or none) explains an empty GitHub
+// list after an owner → member → owner switch. Never the token itself, and never in packaged builds.
+
+type ClaimsProbe = () => Promise<{ org: string | null; orgRole: string | null; sub: string | null }>
+
+/** Reads the claims of a JWT's payload without verifying it; nothing else of the token leaves. */
+export function tokenOrgClaims(token: string): Awaited<ReturnType<ClaimsProbe>> {
+  const payload = token.split('.')[1]
+  let claims: Record<string, unknown> = {}
+  try {
+    const parsed: unknown = JSON.parse(Buffer.from(payload ?? '', 'base64url').toString('utf8'))
+    if (parsed && typeof parsed === 'object') {
+      claims = { ...parsed }
+    }
+  } catch {
+    // Not a JWT: report nothing rather than guess.
+  }
+  const text = (value: unknown): string | null => (typeof value === 'string' ? value : null)
+  return { org: text(claims.org), orgRole: text(claims.org_role), sub: text(claims.sub) }
+}
+
+/**
+ * Dev builds: `globalThis.__orcaCloudTokenClaims()` in the main process (the harness's inspector)
+ * answers the org, role and user the current sandbox token claims.
+ */
+export function installDevTokenClaimsProbe(
+  getAccessToken: () => Promise<string>,
+  packaged: boolean
+): ClaimsProbe | null {
+  if (packaged) {
+    return null
+  }
+  const probe: ClaimsProbe = async () => tokenOrgClaims(await getAccessToken())
+  Object.assign(globalThis, { __orcaCloudTokenClaims: probe })
+  return probe
+}
diff --git a/src/main/hosted-sandbox/hosted-sandbox-install.ts b/src/main/hosted-sandbox/hosted-sandbox-install.ts
index 1094d252345..3b84e6c6d75 100644
--- a/src/main/hosted-sandbox/hosted-sandbox-install.ts
+++ b/src/main/hosted-sandbox/hosted-sandbox-install.ts
@@ -1,3 +1,4 @@
+import { installDevTokenClaimsProbe } from './dev-token-claims-probe'
 import { cloudDevSigningAllowed, withCloudBuildDefaults } from '../cloud-build-defaults'
 import {
   findCloudRuntimeBySandboxId,
@@ -132,6 +133,7 @@ export function installHostedSandbox(
   // A cloud list refresh or a not-found status read asks for the prune now (LC-2).
   setCloudGonePruneRunner(() => accountBackfill.run({ force: true }))
   installLocalCommands(userDataPath)
+  installDevTokenClaimsProbe(() => config.getAccessToken(), app.isPackaged)
   const mcpSync = installCloudMcpSync(userDataPath, {
     baseUrl: config.controlPlaneUrl,
     getAccessToken: config.getAccessToken