diff --git a/internal/cmd/root_test.go b/internal/cmd/root_test.go
index 048dafd5..cdf6080c 100644
--- a/internal/cmd/root_test.go
+++ b/internal/cmd/root_test.go
@@ -349,6 +349,28 @@ func TestRequireAuthPromptsOnlyWhenInteractiveAndStyled(t *testing.T) {
 			t.Errorf("prompt shown %d times for machine output", *asked)
 		}
 	})
+
+	t.Run("never prompts when non-interactive is requested", func(t *testing.T) {
+		t.Setenv("HEY_NONINTERACTIVE", "1")
+		previousStdin, previousStdout, previousStderr := stdinIsTerminal, stdoutIsTerminal, stderrIsTerminal
+		stdinIsTerminal = func() bool { return true }
+		stdoutIsTerminal = func() bool { return true }
+		stderrIsTerminal = func() bool { return true }
+		t.Cleanup(func() {
+			stdinIsTerminal, stdoutIsTerminal, stderrIsTerminal = previousStdin, previousStdout, previousStderr
+		})
+		asked := stubAskToSignIn(t, true)
+		prev := writer
+		writer = output.New(output.Options{Format: output.FormatStyled, Stdout: &bytes.Buffer{}, Stderr: &bytes.Buffer{}})
+		t.Cleanup(func() { writer = prev })
+
+		if err := requireAuth(); err == nil {
+			t.Fatal("expected an auth error")
+		}
+		if *asked != 0 {
+			t.Errorf("prompt shown %d times with HEY_NONINTERACTIVE", *asked)
+		}
+	})
 }
 
 func TestDataCommandWithoutAuthReturnsAuthErrorWhenPiped(t *testing.T) {
diff --git a/skills/embed_test.go b/skills/embed_test.go
new file mode 100644
index 00000000..842e68dc
--- /dev/null
+++ b/skills/embed_test.go
@@ -0,0 +1,35 @@
+package skills
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestHeySkillReusesAuthenticationForUnattendedAgents(t *testing.T) {
+	data, err := FS.ReadFile("hey/SKILL.md")
+	if err != nil {
+		t.Fatal(err)
+	}
+	content := string(data)
+
+	for _, want := range []string{
+		"hey auth status --json",
+		"when an explicit authentication check is needed",
+		"HEY_NONINTERACTIVE=1",
+		"Never run `hey auth login` unattended",
+		"report the task as blocked",
+	} {
+		if !strings.Contains(content, want) {
+			t.Errorf("embedded HEY skill does not contain %q", want)
+		}
+	}
+
+	for _, forbidden := range []string{
+		"run `hey auth login` first",
+		"before the first data command",
+	} {
+		if strings.Contains(content, forbidden) {
+			t.Errorf("embedded HEY skill still requires an authentication preflight with %q", forbidden)
+		}
+	}
+}
diff --git a/skills/hey/SKILL.md b/skills/hey/SKILL.md
index fb52a1ba..d7520cf4 100644
--- a/skills/hey/SKILL.md
+++ b/skills/hey/SKILL.md
@@ -118,7 +118,7 @@ CLI for HEY: mailboxes, labels, collections, email threads, contacts, replies, c
 **MUST follow these rules:**
 
 1. **Choose the right structured output** — use `--jq '<expression>'` to filter or extract fields and `--json` for the full response. Never pipe to an external `jq`; `--jq` is built in and implies `--json`.
-2. **Authentication required** for all data commands — run `hey auth login` first
+2. **Reuse stored authentication** — run the requested data command; it uses stored credentials and refreshes expiring OAuth tokens automatically. If it returns an auth error, report the task as blocked. Use `hey auth status --json` when an explicit authentication check is needed. Never run `hey auth login` unattended; use it only for interactive recovery with the user present.
 3. **HTML output** is available via `--html` for commands that return HTML content
 4. **Linked mail accounts share one login** — use `hey account list --json`, then `--account <id|all>` when a task must target one account
 5. **Local HEY configuration requires human trust** — never run `hey config trust-local` without the user's explicit approval
@@ -246,7 +246,7 @@ notice on stderr. Both need list data, so they work on `hey box list`, `hey box
 | List journal entries | `hey journal list --json` |
 | Read journal entry | `hey journal read 2024-03-15 --json` |
 | Write journal entry | `hey journal write "Shipped the pagination fix."` (empty content removes the entry) |
-| Check auth status | `hey auth status` |
+| Check auth status | `hey auth status --json` |
 | Print bearer token | `hey auth token` (refuses a `--cookie` login) |
 | Launch TUI | `hey tui` (Ctrl+A switches linked mail accounts) |
 
@@ -751,20 +751,27 @@ error.
 
 ### Authentication
 
+Data commands use the credentials HEY already stores and refresh expiring OAuth tokens automatically. Run the requested data command without a login preflight. Use `hey auth status --json` when the user asks for authentication status or when an explicit authentication check helps diagnose a failure; it reports whether credentials are available without changing them.
+
+If a data command returns exit code 3 with `"code": "auth"`, report that authentication is required and the task is blocked. Tell the user to run `hey auth login`; do not run it for them unattended.
+
+Piped, machine-output and non-TTY commands do not prompt for sign-in. When an agent harness runs commands under a PTY, set `HEY_NONINTERACTIVE=1` so a missing login returns the same actionable auth error instead of opening an interactive prompt.
+
 ```bash
-hey auth login                                # Log in (browser-based OAuth)
-hey auth status                               # Check if authenticated
-hey auth logout                               # Log out
-hey login / hey logout                        # Shortcuts for the two above
-hey setup omarchy                             # Omarchy only: put HEY in the bar. The interactive
-                                              # sign-in offer never fires for agents (non-TTY,
-                                              # machine output), so this command is the way
-hey setup                                     # First-run wizard: sign in + connect coding agents
-HEY_NONINTERACTIVE=1 hey setup --json         # No prompts and no OAuth wait — but still
-                                              # installs agent skills and records onboarding;
-                                              # use `hey doctor` to inspect without changes.
-                                              # (Without HEY_NONINTERACTIVE, a terminal on
-                                              # stdin still starts browser sign-in.)
+hey auth status --json                         # Inspect stored authentication without changing it
+HEY_NONINTERACTIVE=1 hey box list --json       # A PTY-safe unattended data command
+hey auth login                                 # Interactive browser recovery, with the user present
+hey auth logout                                # Log out
+hey login / hey logout                         # Shortcuts for the two above
+hey setup omarchy                              # Omarchy only: put HEY in the bar. The interactive
+                                               # sign-in offer never fires for agents (non-TTY,
+                                               # machine output), so this command is the way
+hey setup                                      # First-run wizard: sign in + connect coding agents
+HEY_NONINTERACTIVE=1 hey setup --json          # No prompts and no OAuth wait — but still
+                                               # installs agent skills and records onboarding;
+                                               # use `hey doctor` to inspect without changes.
+                                               # (Without HEY_NONINTERACTIVE, a terminal on
+                                               # stdin still starts browser sign-in.)
 ```
 
-If a command fails with an auth error, run `hey auth status` to check, then `hey auth login` to re-authenticate.
+Run `hey auth login` only when the user is present and explicitly asks to authenticate.