feat(token): mint TAT via unified OAuth v3 Token Endpoint (#1408)

cmd/config/init_probe.go

@@ -33,15 +33,16 @@ const probeTimeout = 3 * time.Second
 //
 //  1. A TAT request using the just-saved credentials. credential.FetchTAT
 //     returns a typed errs.* error (via the shared classifyTATResponseCode)
-//     only when the server deterministically rejected the credentials — a
-//     non-zero TAT body code, classified as CategoryConfig / SubtypeInvalidClient
-//     (10003 / 10014) or whatever codemeta maps. That typed error is propagated
-//     so the root dispatcher renders the canonical envelope and `config init`
-//     exits non-zero — identical to how every other token-resolving command
-//     reports the same bad credentials. Ambiguous failures (transport errors,
-//     HTTP non-200, JSON parse errors, timeouts) come back as raw untyped
-//     errors and are swallowed (return nil), so valid configurations are never
-//     disturbed by upstream noise. errs.IsTyped is the discriminator.
+//     only when the unified Token Endpoint deterministically rejected the
+//     credentials — an OAuth2 invalid_client / unauthorized_client classified as
+//     CategoryConfig / SubtypeInvalidClient, or whatever codemeta maps. That
+//     typed error is propagated so the root dispatcher renders the canonical
+//     envelope and `config init` exits non-zero — identical to how every other
+//     token-resolving command reports the same bad credentials. Ambiguous
+//     failures (transport errors, transient 5xx/server_error, JSON parse errors,
+//     timeouts) come back as raw untyped errors and are swallowed (return nil),
+//     so valid configurations are never disturbed by upstream noise.
+//     errs.IsTyped is the discriminator.
 //
 //  2. If TAT succeeded, a POST to the probe endpoint is fired. The outcome of
 //     that call (success, server error, timeout, parse failure) is always

cmd/config/init_probe_test.go

@@ -31,10 +31,10 @@ type fakeRT struct {
 
 func (f *fakeRT) RoundTrip(req *http.Request) (*http.Response, error) {
 	switch {
-	case strings.HasSuffix(req.URL.Path, "/auth/v3/tenant_access_token/internal"):
+	case strings.HasSuffix(req.URL.Path, "/oauth/v3/token"):
 		f.tatCalls++
 		if f.tatHandler == nil {
-			return jsonResp(200, `{"code":0,"tenant_access_token":"t-ok"}`), nil
+			return jsonResp(200, `{"code":0,"access_token":"t-ok","token_type":"Bearer"}`), nil
 		}
 		return f.tatHandler(req)
 	case strings.HasSuffix(req.URL.Path, "/application/v6/larksuite_cli_app/probe"):
@@ -84,14 +84,15 @@ func fakeFactory(t *testing.T, rt http.RoundTripper) (*cmdutil.Factory, *bytes.B
 }
 
 // assertConfigRejection asserts runProbe propagated a deterministic credential
-// rejection: a *errs.ConfigError (CategoryConfig / SubtypeInvalidClient) with
-// the expected upstream code. This is the same typed error every other
-// token-resolving command returns for the same bad credentials, and nothing is
-// written to stderr (the root dispatcher renders the envelope).
-func assertConfigRejection(t *testing.T, err error, errBuf *bytes.Buffer, wantCode int) {
+// rejection: a *errs.ConfigError (CategoryConfig / SubtypeInvalidClient). This
+// is the same typed error every other token-resolving command returns for the
+// same bad credentials, and nothing is written to stderr (the root dispatcher
+// renders the envelope). The numeric code is not asserted: the unified v3 Token
+// Endpoint reports invalid_client via the OAuth2 error string, not a Lark code.
+func assertConfigRejection(t *testing.T, err error, errBuf *bytes.Buffer) {
 	t.Helper()
 	if err == nil {
-		t.Fatalf("expected *errs.ConfigError (code %d), got nil", wantCode)
+		t.Fatal("expected *errs.ConfigError, got nil")
 	}
 	var cfgErr *errs.ConfigError
 	if !errors.As(err, &cfgErr) {
@@ -103,9 +104,6 @@ func assertConfigRejection(t *testing.T, err error, errBuf *bytes.Buffer, wantCo
 	if cfgErr.Subtype != errs.SubtypeInvalidClient {
 		t.Errorf("Subtype = %q, want %q", cfgErr.Subtype, errs.SubtypeInvalidClient)
 	}
-	if cfgErr.Code != wantCode {
-		t.Errorf("Code = %d, want %d", cfgErr.Code, wantCode)
-	}
 	if errBuf.Len() != 0 {
 		t.Errorf("runProbe must not write to stderr, got: %q", errBuf.String())
 	}
@@ -123,11 +121,13 @@ func assertSilent(t *testing.T, err error, errBuf *bytes.Buffer) {
 	}
 }
 
-// 10003 (bad / non-existent app_id) → ConfigError/InvalidClient, propagated.
-func TestRunProbe_TATCode10003_ReturnsConfigError(t *testing.T) {
+// invalid_client (bad / non-existent app_id or wrong secret) → the v3 Token
+// Endpoint returns HTTP 400 with the OAuth2 error → ConfigError/InvalidClient,
+// propagated. The probe endpoint must not be called when TAT fails.
+func TestRunProbe_TATInvalidClient_ReturnsConfigError(t *testing.T) {
 	rt := &fakeRT{
 		tatHandler: func(req *http.Request) (*http.Response, error) {
-			return jsonResp(200, `{"code":10003,"msg":"invalid param"}`), nil
+			return jsonResp(400, `{"error":"invalid_client","error_description":"The client secret is invalid.","code":20002}`), nil
 		},
 	}
 	f, errBuf := fakeFactory(t, rt)
@@ -137,28 +137,27 @@ func TestRunProbe_TATCode10003_ReturnsConfigError(t *testing.T) {
 	if rt.probeCalls != 0 {
 		t.Error("probe endpoint must not be called when TAT fails")
 	}
-	assertConfigRejection(t, err, errBuf, 10003)
+	assertConfigRejection(t, err, errBuf)
 }
 
-// 10014 (real app_id + wrong secret) → ConfigError/InvalidClient via codemeta —
-// the most common real-world rejection, propagated.
-func TestRunProbe_TATCode10014_ReturnsConfigError(t *testing.T) {
+// unauthorized_client is treated as the same credential rejection, propagated.
+func TestRunProbe_TATUnauthorizedClient_ReturnsConfigError(t *testing.T) {
 	rt := &fakeRT{
 		tatHandler: func(req *http.Request) (*http.Response, error) {
-			return jsonResp(200, `{"code":10014,"msg":"app secret invalid"}`), nil
+			return jsonResp(401, `{"error":"unauthorized_client","error_description":"client not authorized"}`), nil
 		},
 	}
 	f, errBuf := fakeFactory(t, rt)
-	assertConfigRejection(t, runProbe(context.Background(), f, "cli_x", "secret_y", core.BrandFeishu), errBuf, 10014)
+	assertConfigRejection(t, runProbe(context.Background(), f, "cli_x", "secret_y", core.BrandFeishu), errBuf)
 }
 
-// Any non-zero body code is a deterministic rejection and propagates (typed).
-// An unrecognized code falls back to *errs.APIError via BuildAPIError — still
-// typed, so the probe still surfaces it rather than swallowing.
-func TestRunProbe_TATUnknownBodyCode_Propagates(t *testing.T) {
+// Any other deterministic client-side OAuth error (e.g. invalid_scope) falls
+// back to *errs.APIError via BuildAPIError — still typed, so the probe surfaces
+// it rather than swallowing — but is not a credential (ConfigError) rejection.
+func TestRunProbe_TATOtherClientError_Propagates(t *testing.T) {
 	rt := &fakeRT{
 		tatHandler: func(req *http.Request) (*http.Response, error) {
-			return jsonResp(200, `{"code":99999,"msg":"future-unknown"}`), nil
+			return jsonResp(400, `{"code":20068,"error":"invalid_scope","error_description":"unauthorized scope"}`), nil
 		},
 	}
 	f, errBuf := fakeFactory(t, rt)

internal/core/types.go

@@ -22,6 +22,12 @@ func ParseBrand(value string) LarkBrand {
 	return BrandFeishu
 }
 
+// OAuthTokenV3Path is the unified OAuth 2.0 Token Endpoint path on the accounts
+// domain. It serves every grant type (client_credentials for TAT,
+// authorization_code / device_code / refresh_token for UAT) and replaces the
+// legacy per-token endpoints (e.g. /open-apis/auth/v3/tenant_access_token/internal).
+const OAuthTokenV3Path = "/oauth/v3/token"
+
 // Endpoints holds resolved endpoint URLs for different Lark services.
 type Endpoints struct {
 	Open     string // e.g. "https://open.feishu.cn"

internal/core/types_test.go

@@ -42,6 +42,11 @@ func TestResolveEndpoints_EmptyDefaultsToFeishu(t *testing.T) {
 	if ep.Open != "https://open.feishu.cn" {
 		t.Errorf("Open = %q, want feishu.cn for empty brand", ep.Open)
 	}
+	// The unified OAuth v3 Token Endpoint mints TAT on the accounts domain;
+	// pin the default-brand host so a stray non-production domain revert is caught.
+	if ep.Accounts != "https://accounts.feishu.cn" {
+		t.Errorf("Accounts = %q, want accounts.feishu.cn for empty brand", ep.Accounts)
+	}
 }
 
 func TestResolveOpenBaseURL(t *testing.T) {

internal/credential/default_provider.go

@@ -19,33 +19,44 @@ import (
 	extcred "github.com/larksuite/cli/extension/credential"
 )
 
-// classifyTATResponseCode wraps a non-zero TAT endpoint response code into the
-// canonical typed error. The TAT mint endpoint reports invalid credentials
-// with two distinct codes:
+// classifyTATResponseCode wraps a deterministic (non-transient) failure from the
+// unified Token Endpoint into the canonical typed errs.* error. The v3 endpoint
+// reports failures using the OAuth 2.0 model — an `error` string plus an
+// optional numeric `code` — instead of the legacy `{code, msg}` shape.
 //
-//   - 10003: bad app_id format or non-existent app_id ("invalid param")
-//   - 10014: invalid app_secret ("app secret invalid")
-//
-// Both surface as CategoryConfig/InvalidClient from the user's perspective —
-// the configured credentials cannot mint a tenant access token. 10014 is
-// globally mapped in codemeta (TAT-mint-specific variant of OAuth 99991543).
-// 10003 is NOT globally mapped because in other Lark endpoints it carries
-// unrelated semantics (e.g. task API uses 10003 for permission denied), so
-// the override stays local to this TAT call site instead of leaking into the
-// shared codemeta table.
-func classifyTATResponseCode(code int, msg, brand, appID string) error {
-	if code == 10003 {
+// invalid_client / unauthorized_client mean the configured app_id/app_secret
+// cannot mint a token; from the user's perspective that is the same actionable
+// CategoryConfig/InvalidClient failure the legacy 10003/10014 codes produced.
+// Every other deterministic error falls through to BuildAPIError, which still
+// yields a typed error so probe callers (errs.IsTyped) surface it rather than
+// swallowing it. Transient/server-side failures (5xx / server_error) are
+// filtered out by FetchTAT before this is called, so they stay untyped.
+func classifyTATResponseCode(code int, oauthErr, errDesc, brand, appID string) error {
+	msg := errDesc
+	if msg == "" {
+		msg = oauthErr
+	}
+	switch oauthErr {
+	case "invalid_client", "unauthorized_client":
 		return errs.NewConfigError(errs.SubtypeInvalidClient, "%s", msg).
 			WithCode(code).
 			WithHint("%s", errclass.ConfigHint(errs.SubtypeInvalidClient))
 	}
-	return errclass.BuildAPIError(map[string]any{
+	if err := errclass.BuildAPIError(map[string]any{
 		"code": code,
 		"msg":  msg,
 	}, errclass.ClassifyContext{
 		Brand: brand,
 		AppID: appID,
-	})
+	}); err != nil {
+		return err
+	}
+	// BuildAPIError returns nil for code 0 (Feishu's success convention), but this
+	// function is only reached once FetchTAT has ruled out success — a non-credential
+	// OAuth error (e.g. invalid_scope) can arrive with code 0 and is still a
+	// deterministic rejection. Back it with a typed APIError so callers never receive
+	// the ("", nil) "empty token, no error" pair.
+	return errs.NewAPIError(errs.SubtypeUnknown, "%s", msg).WithCode(code)
 }
 
 // DefaultAccountProvider resolves account from config.json via keychain.
@@ -146,8 +157,8 @@ func (p *DefaultTokenProvider) resolveUAT(ctx context.Context) (*TokenResult, er
 	return &TokenResult{Token: token, Scopes: scopes}, nil
 }
 
-// resolveTAT resolves a tenant access token. Result is cached after first call.
-// NOTE: Uses sync.Once — only the context from the first call is used.
+// resolveTAT resolves a tenant access token. The result is cached after the first
+// call via sync.Once — only the context from the first call is used.
 func (p *DefaultTokenProvider) resolveTAT(ctx context.Context) (*TokenResult, error) {
 	p.tatOnce.Do(func() {
 		p.tatResult, p.tatErr = p.doResolveTAT(ctx)

internal/credential/default_provider_test.go

@@ -19,18 +19,16 @@ func TestDefaultAccountProvider_Implements(t *testing.T) {
 	var _ DefaultAccountResolver = &DefaultAccountProvider{}
 }
 
-// TestClassifyTATResponseCode_10003_MapsToInvalidClient pins that the TAT
-// endpoint's "invalid param" code surfaces as CategoryConfig/InvalidClient.
-// Reason: a bad or non-existent app_id triggers 10003 on the TAT mint endpoint,
-// which from the user's perspective is the same actionable failure as 10014
-// ("app secret invalid") — both mean the configured credentials cannot mint a
-// tenant access token. The global codemeta intentionally does not map 10003
-// because in other Lark endpoints 10003 carries unrelated semantics (e.g. task
-// API uses it for permission denied), so the override is local to this site.
-func TestClassifyTATResponseCode_10003_MapsToInvalidClient(t *testing.T) {
-	err := classifyTATResponseCode(10003, "invalid param", "feishu", "cli_app_x")
+// TestClassifyTATResponseCode_InvalidClient_MapsToInvalidClient pins that the
+// unified Token Endpoint's OAuth2 invalid_client error surfaces as
+// CategoryConfig/InvalidClient — the configured app_id/app_secret cannot mint a
+// tenant access token, the same actionable failure the legacy 10003/10014 codes
+// produced. The numeric code is intentionally not asserted: the v3 endpoint may
+// return invalid_client with no Lark code (code defaults to 0).
+func TestClassifyTATResponseCode_InvalidClient_MapsToInvalidClient(t *testing.T) {
+	err := classifyTATResponseCode(0, "invalid_client", "client authentication failed", "feishu", "cli_app_x")
 	if err == nil {
-		t.Fatal("expected non-nil error for code=10003")
+		t.Fatal("expected non-nil error for invalid_client")
 	}
 	var cfgErr *errs.ConfigError
 	if !errors.As(err, &cfgErr) {
@@ -42,22 +40,16 @@ func TestClassifyTATResponseCode_10003_MapsToInvalidClient(t *testing.T) {
 	if cfgErr.Subtype != errs.SubtypeInvalidClient {
 		t.Errorf("Subtype = %q, want %q", cfgErr.Subtype, errs.SubtypeInvalidClient)
 	}
-	if cfgErr.Code != 10003 {
-		t.Errorf("Code = %d, want 10003", cfgErr.Code)
-	}
 	if cfgErr.Hint == "" {
 		t.Error("Hint must be non-empty so the user gets a recovery action")
 	}
 }
 
-// TestClassifyTATResponseCode_10014_RoutesViaCodeMeta pins that 10014 still
-// goes through the global BuildAPIError path (codemeta entry) so the override
-// for 10003 does not regress the existing mapping.
-func TestClassifyTATResponseCode_10014_RoutesViaCodeMeta(t *testing.T) {
-	err := classifyTATResponseCode(10014, "app secret invalid", "feishu", "cli_app_x")
-	if err == nil {
-		t.Fatal("expected non-nil error for code=10014")
-	}
+// TestClassifyTATResponseCode_UnauthorizedClient_MapsToInvalidClient pins that
+// unauthorized_client is treated as the same credential failure as
+// invalid_client.
+func TestClassifyTATResponseCode_UnauthorizedClient_MapsToInvalidClient(t *testing.T) {
+	err := classifyTATResponseCode(0, "unauthorized_client", "client not authorized", "feishu", "cli_app_x")
 	var cfgErr *errs.ConfigError
 	if !errors.As(err, &cfgErr) {
 		t.Fatalf("expected *errs.ConfigError, got %T: %v", err, err)
@@ -65,21 +57,38 @@ func TestClassifyTATResponseCode_10014_RoutesViaCodeMeta(t *testing.T) {
 	if cfgErr.Subtype != errs.SubtypeInvalidClient {
 		t.Errorf("Subtype = %q, want %q", cfgErr.Subtype, errs.SubtypeInvalidClient)
 	}
-	if cfgErr.Code != 10014 {
-		t.Errorf("Code = %d, want 10014", cfgErr.Code)
-	}
 }
 
-// TestClassifyTATResponseCode_UnknownCodeFallsThrough pins that codes outside
-// the credential set fall through to the generic BuildAPIError fallback
-// (CategoryAPI/SubtypeUnknown) — the override is narrow and intentional.
-func TestClassifyTATResponseCode_UnknownCodeFallsThrough(t *testing.T) {
-	err := classifyTATResponseCode(99999999, "some unknown failure", "feishu", "cli_app_x")
+// TestClassifyTATResponseCode_OtherErrorFallsThrough pins that OAuth errors
+// outside the credential set fall through to the generic BuildAPIError fallback
+// — still typed, but not a ConfigError. The mapping is narrow and intentional.
+func TestClassifyTATResponseCode_OtherErrorFallsThrough(t *testing.T) {
+	err := classifyTATResponseCode(20068, "invalid_scope", "unauthorized scope", "feishu", "cli_app_x")
 	if err == nil {
-		t.Fatal("expected non-nil error for unmapped code")
+		t.Fatal("expected non-nil error for invalid_scope")
 	}
 	var cfgErr *errs.ConfigError
 	if errors.As(err, &cfgErr) {
-		t.Fatalf("unmapped code must not be classified as ConfigError, got %T", err)
+		t.Fatalf("invalid_scope must not be classified as ConfigError, got %T", err)
+	}
+}
+
+// TestClassifyTATResponseCode_CodeZeroOtherError_StillTyped pins the code-0
+// backstop: a non-credential OAuth error (e.g. invalid_scope) that arrives with no
+// numeric code (code 0) must still produce a non-nil typed error. BuildAPIError
+// returns nil for code 0 (Feishu's success convention); without the backstop,
+// FetchTAT would surface this deterministic rejection as ("", nil) — an empty token
+// with no error.
+func TestClassifyTATResponseCode_CodeZeroOtherError_StillTyped(t *testing.T) {
+	err := classifyTATResponseCode(0, "invalid_scope", "the requested scope is not granted", "feishu", "cli_app_x")
+	if err == nil {
+		t.Fatal("expected non-nil error for code-0 invalid_scope (must not be swallowed as success)")
+	}
+	if !errs.IsTyped(err) {
+		t.Fatalf("expected a typed errs.* error, got %T %v", err, err)
+	}
+	var cfgErr *errs.ConfigError
+	if errors.As(err, &cfgErr) {
+		t.Fatalf("code-0 invalid_scope must not be a ConfigError, got %T", err)
 	}
 }

internal/credential/tat_fetch.go

@@ -4,46 +4,47 @@
 package credential
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
+	"net/url"
+	"strings"
 
 	"github.com/larksuite/cli/internal/core"
 )
 
-// FetchTAT performs a single HTTP POST to mint a tenant access token with the
-// given credentials. It does not read configuration or keychain, so callers
-// that already hold plaintext credentials (e.g. the post-`config init` probe)
-// can validate them without a second keychain round-trip.
+// FetchTAT performs a single HTTP POST to mint a tenant access token via the
+// unified OAuth 2.0 Token Endpoint ({accounts}/oauth/v3/token) using the
+// client_credentials grant with client_secret_post authentication. It does not
+// read configuration or keychain, so callers that already hold plaintext
+// credentials (e.g. the post-`config init` probe) can validate them without a
+// second keychain round-trip.
 //
-// A non-zero TAT response code means the server inspected the payload and
-// rejected the credentials; FetchTAT returns the canonical typed error from
-// classifyTATResponseCode — the SAME classification doResolveTAT (and thus
-// every token-resolving command) produces, so callers see one consistent
-// envelope (CategoryConfig / SubtypeInvalidClient for 10003 / 10014, etc.).
-// Transport, HTTP-status and JSON-parse failures are returned raw (untyped),
-// leaving them ambiguous; a caller can use errs.IsTyped to tell a deterministic
-// credential rejection apart from upstream/transport noise.
+// A deterministic client-side rejection (e.g. invalid_client) returns the
+// canonical typed error from classifyTATResponseCode — the SAME classification
+// doResolveTAT (and thus every token-resolving command) produces, so callers
+// see one consistent envelope. Transport failures, unreadable/unparseable
+// bodies, and transient server-side failures (5xx / server_error) are returned
+// raw (untyped), leaving them ambiguous; a caller can use errs.IsTyped to tell a
+// deterministic credential rejection apart from upstream/transport noise.
 //
 // The caller owns the context timeout.
 func FetchTAT(ctx context.Context, httpClient *http.Client, brand core.LarkBrand, appID, appSecret string) (string, error) {
 	ep := core.ResolveEndpoints(brand)
-	url := ep.Open + "/open-apis/auth/v3/tenant_access_token/internal"
+	endpoint := ep.Accounts + core.OAuthTokenV3Path
 
-	body, err := json.Marshal(map[string]string{
-		"app_id":     appID,
-		"app_secret": appSecret,
-	})
-	if err != nil {
-		return "", fmt.Errorf("failed to marshal TAT request: %w", err)
-	}
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
+	form := url.Values{}
+	form.Set("grant_type", "client_credentials")
+	form.Set("client_id", appID)
+	form.Set("client_secret", appSecret)
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, strings.NewReader(form.Encode()))
 	if err != nil {
 		return "", err
 	}
-	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 
 	resp, err := httpClient.Do(req)
 	if err != nil {
@@ -51,20 +52,51 @@ func FetchTAT(ctx context.Context, httpClient *http.Client, brand core.LarkBrand
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode != http.StatusOK {
-		return "", fmt.Errorf("TAT API returned HTTP %d", resp.StatusCode)
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	if err != nil {
+		return "", fmt.Errorf("failed to read TAT response: %w", err)
 	}
 
 	var result struct {
-		Code              int    `json:"code"`
-		Msg               string `json:"msg"`
-		TenantAccessToken string `json:"tenant_access_token"`
+		Code             int    `json:"code"`
+		AccessToken      string `json:"access_token"`
+		Error            string `json:"error"`
+		ErrorDescription string `json:"error_description"`
+		Msg              string `json:"msg"`
 	}
-	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
-		return "", fmt.Errorf("failed to parse TAT response: %w", err)
+	if err := json.Unmarshal(body, &result); err != nil {
+		// An unparseable body is ambiguous (covers non-JSON error pages and
+		// truncated payloads); stay untyped so probe callers treat it as noise.
+		return "", fmt.Errorf("failed to parse TAT response (HTTP %d): %w", resp.StatusCode, err)
 	}
-	if result.Code != 0 {
-		return "", classifyTATResponseCode(result.Code, result.Msg, string(brand), appID)
+
+	if result.Code == 0 && result.AccessToken != "" {
+		return result.AccessToken, nil
 	}
-	return result.TenantAccessToken, nil
+
+	// Transient/server-side failures stay untyped so probe callers stay silent and
+	// retryers can back off; only deterministic client rejections are typed. Covers
+	// 5xx, HTTP 429 rate-limit, and the OAuth transient error strings (server_error,
+	// temporarily_unavailable, slow_down) — matching the legacy "non-2xx is noise"
+	// behavior so a rate-limited probe is not surfaced as a hard credential error.
+	if resp.StatusCode >= 500 || resp.StatusCode == http.StatusTooManyRequests ||
+		result.Error == "server_error" || result.Error == "temporarily_unavailable" ||
+		result.Error == "slow_down" {
+		return "", fmt.Errorf("TAT endpoint transient failure (HTTP %d, code=%d, error=%q): %s",
+			resp.StatusCode, result.Code, result.Error, result.ErrorDescription)
+	}
+
+	// A 2xx with neither token nor error is a malformed success — ambiguous, untyped.
+	if result.Code == 0 && result.Error == "" {
+		return "", fmt.Errorf("TAT response missing access_token (HTTP %d)", resp.StatusCode)
+	}
+
+	// Prefer the OAuth error_description; fall back to the legacy Lark `msg` so a
+	// gateway-level {code, msg} response (carrying no OAuth fields) still yields a
+	// non-empty typed message instead of a bare "API error: [code]".
+	desc := result.ErrorDescription
+	if desc == "" {
+		desc = result.Msg
+	}
+	return "", classifyTATResponseCode(result.Code, result.Error, desc, string(brand), appID)
 }

internal/credential/tat_fetch_test.go

@@ -44,7 +44,7 @@ func (s *stubRoundTripper) RoundTrip(req *http.Request) (*http.Response, error)
 func TestFetchTAT_Success(t *testing.T) {
 	rt := &stubRoundTripper{
 		respCode: 200,
-		respBody: `{"code":0,"tenant_access_token":"t-abc","msg":"ok"}`,
+		respBody: `{"code":0,"access_token":"t-abc","token_type":"Bearer","expires_in":7200}`,
 	}
 	hc := &http.Client{Transport: rt}
 
@@ -55,24 +55,33 @@ func TestFetchTAT_Success(t *testing.T) {
 	if token != "t-abc" {
 		t.Errorf("token = %q, want t-abc", token)
 	}
-	if rt.gotReq.URL.String() != "https://open.feishu.cn/open-apis/auth/v3/tenant_access_token/internal" {
+	if rt.gotReq.URL.String() != "https://accounts.feishu.cn/oauth/v3/token" {
 		t.Errorf("url = %s", rt.gotReq.URL.String())
 	}
-	if !strings.Contains(rt.gotBody, `"app_id":"cli_app"`) || !strings.Contains(rt.gotBody, `"app_secret":"secret_x"`) {
-		t.Errorf("request body missing credentials: %s", rt.gotBody)
+	if ct := rt.gotReq.Header.Get("Content-Type"); ct != "application/x-www-form-urlencoded" {
+		t.Errorf("Content-Type = %q, want application/x-www-form-urlencoded", ct)
+	}
+	// client_secret_post: grant_type + client_id + client_secret in the form body.
+	for _, want := range []string{"grant_type=client_credentials", "client_id=cli_app", "client_secret=secret_x"} {
+		if !strings.Contains(rt.gotBody, want) {
+			t.Errorf("request body missing %q: %s", want, rt.gotBody)
+		}
 	}
 }
 
-// 10003 (bad / non-existent app_id, "invalid param") is classified locally by
+// invalid_client (wrong app_id/app_secret on the client_credentials grant) is a
+// deterministic client-side rejection that FetchTAT routes to
 // classifyTATResponseCode as CategoryConfig / SubtypeInvalidClient — the same
 // typed error doResolveTAT (and thus every token-resolving command) returns.
-func TestFetchTAT_Code10003_ConfigInvalidClient(t *testing.T) {
-	rt := &stubRoundTripper{respCode: 200, respBody: `{"code":10003,"msg":"invalid param"}`}
+// The v3 endpoint reports it as HTTP 400 with the OAuth2 error body (wrong
+// secret → code 20002, unknown app → code 20048).
+func TestFetchTAT_InvalidClient_ConfigInvalidClient(t *testing.T) {
+	rt := &stubRoundTripper{respCode: 400, respBody: `{"error":"invalid_client","error_description":"The client secret is invalid.","code":20002}`}
 	hc := &http.Client{Transport: rt}
 
 	token, err := FetchTAT(context.Background(), hc, core.BrandFeishu, "cli_app", "secret_x")
 	if err == nil {
-		t.Fatal("expected error for code 10003")
+		t.Fatal("expected error for invalid_client")
 	}
 	if token != "" {
 		t.Errorf("token = %q, want empty", token)
@@ -87,52 +96,115 @@ func TestFetchTAT_Code10003_ConfigInvalidClient(t *testing.T) {
 	if cfgErr.Subtype != errs.SubtypeInvalidClient {
 		t.Errorf("Subtype = %q, want %q", cfgErr.Subtype, errs.SubtypeInvalidClient)
 	}
-	if cfgErr.Code != 10003 {
-		t.Errorf("Code = %d, want 10003", cfgErr.Code)
-	}
 }
 
-// 10014 ("app secret invalid") — the most common real-world rejection (real
-// app_id + wrong secret) — is globally mapped in codemeta to
-// CategoryConfig / SubtypeInvalidClient via BuildAPIError.
-func TestFetchTAT_Code10014_ConfigInvalidClient(t *testing.T) {
-	rt := &stubRoundTripper{respCode: 200, respBody: `{"code":10014,"msg":"app secret invalid"}`}
-	hc := &http.Client{Transport: rt}
-
-	_, err := FetchTAT(context.Background(), hc, core.BrandFeishu, "cli_app", "secret_x")
-	var cfgErr *errs.ConfigError
-	if !errors.As(err, &cfgErr) {
-		t.Fatalf("error not *errs.ConfigError: %T %v", err, err)
-	}
-	if cfgErr.Subtype != errs.SubtypeInvalidClient || cfgErr.Code != 10014 {
-		t.Errorf("got Subtype=%q Code=%d, want invalid_client/10014", cfgErr.Subtype, cfgErr.Code)
-	}
-}
-
-// Any non-zero body code is a deterministic server-side rejection, so it
-// always yields a typed error (errs.IsTyped). An unrecognized code falls back
-// to CategoryAPI / SubtypeUnknown via BuildAPIError — still typed, so a probe
-// caller still surfaces it rather than silently swallowing.
-func TestFetchTAT_UnknownBodyCode_Typed(t *testing.T) {
-	rt := &stubRoundTripper{respCode: 200, respBody: `{"code":99999,"msg":"future-unknown"}`}
+// Any other deterministic client-side OAuth error (e.g. invalid_scope) still
+// yields a typed error (errs.IsTyped) via BuildAPIError — so a probe caller
+// surfaces it rather than silently swallowing it — but is NOT classified as a
+// credential (invalid_client) problem.
+func TestFetchTAT_OtherClientError_Typed(t *testing.T) {
+	rt := &stubRoundTripper{respCode: 400, respBody: `{"code":20068,"error":"invalid_scope","error_description":"unauthorized scope"}`}
 	hc := &http.Client{Transport: rt}
 
 	_, err := FetchTAT(context.Background(), hc, core.BrandFeishu, "cli_app", "secret_x")
 	if err == nil {
-		t.Fatal("expected error for code 99999")
+		t.Fatal("expected error for invalid_scope")
 	}
 	if !errs.IsTyped(err) {
 		t.Fatalf("expected a typed errs.* error, got %T %v", err, err)
 	}
-	var apiErr *errs.APIError
-	if !errors.As(err, &apiErr) {
-		t.Errorf("unknown code should fall back to *errs.APIError, got %T", err)
+	var cfgErr *errs.ConfigError
+	if errors.As(err, &cfgErr) {
+		t.Errorf("invalid_scope must not be classified as ConfigError/InvalidClient, got %T", err)
 	}
 }
 
-// Non-2xx HTTP is ambiguous (not a payload-level credential rejection) — it
-// must stay UNTYPED so a probe caller treats it as upstream noise and stays
-// silent.
+// A deterministic OAuth error that arrives WITHOUT a numeric code (code defaults to
+// 0) must still surface as a non-nil typed error — never the ("", nil) success pair.
+// Guards the code-0 backstop in classifyTATResponseCode: BuildAPIError returns nil
+// for code 0, which would otherwise swallow this rejection into an empty-token success.
+func TestFetchTAT_OtherClientError_CodeZero_Typed(t *testing.T) {
+	rt := &stubRoundTripper{respCode: 400, respBody: `{"error":"invalid_scope","error_description":"the requested scope is not granted"}`}
+	hc := &http.Client{Transport: rt}
+
+	tok, err := FetchTAT(context.Background(), hc, core.BrandFeishu, "cli_app", "secret_x")
+	if err == nil {
+		t.Fatal("expected non-nil error for code-0 invalid_scope (must not return empty token + nil error)")
+	}
+	if tok != "" {
+		t.Errorf("token = %q, want empty", tok)
+	}
+	if !errs.IsTyped(err) {
+		t.Fatalf("expected a typed errs.* error, got %T %v", err, err)
+	}
+}
+
+// A gateway-style {code, msg} error (no OAuth error / error_description fields)
+// must still surface its msg on the typed error, not degrade to a generic
+// "API error: [code]". Guards the legacy-msg fallback in FetchTAT.
+func TestFetchTAT_LarkStyleMsg_FallsBackOnTypedError(t *testing.T) {
+	rt := &stubRoundTripper{respCode: 400, respBody: `{"code":99999,"msg":"app ticket invalid"}`}
+	hc := &http.Client{Transport: rt}
+
+	_, err := FetchTAT(context.Background(), hc, core.BrandFeishu, "cli_app", "secret_x")
+	if err == nil {
+		t.Fatal("expected error for {code, msg} response")
+	}
+	if !errs.IsTyped(err) {
+		t.Fatalf("expected a typed errs.* error, got %T %v", err, err)
+	}
+	if !strings.Contains(err.Error(), "app ticket invalid") {
+		t.Errorf("typed error must carry the Lark msg, got: %v", err)
+	}
+}
+
+// Transient server-side failures (5xx / server_error) are NOT deterministic
+// credential rejections — they must stay UNTYPED so a probe caller treats them
+// as upstream noise and stays silent (and retryers can back off).
+func TestFetchTAT_ServerError_Untyped(t *testing.T) {
+	rt := &stubRoundTripper{respCode: 500, respBody: `{"code":20050,"error":"server_error","error_description":"please retry"}`}
+	hc := &http.Client{Transport: rt}
+
+	_, err := FetchTAT(context.Background(), hc, core.BrandFeishu, "cli_app", "secret_x")
+	if err == nil {
+		t.Fatal("expected error for server_error")
+	}
+	if errs.IsTyped(err) {
+		t.Errorf("server_error must be UNTYPED (transient), got typed %T %v", err, err)
+	}
+}
+
+// Rate-limiting is transient, not a deterministic credential rejection — an HTTP
+// 429 (even with a parseable OAuth body) and the OAuth slow_down error must both
+// stay UNTYPED so a rate-limited probe stays silent and retryers can back off.
+func TestFetchTAT_RateLimit_Untyped(t *testing.T) {
+	cases := []struct {
+		name string
+		code int
+		body string
+	}{
+		{"http 429", 429, `{"code":99991400,"error":"too_many_requests","error_description":"rate limit exceeded"}`},
+		{"oauth slow_down", 200, `{"error":"slow_down","error_description":"polling too fast"}`},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			rt := &stubRoundTripper{respCode: tc.code, respBody: tc.body}
+			hc := &http.Client{Transport: rt}
+
+			_, err := FetchTAT(context.Background(), hc, core.BrandFeishu, "cli_app", "secret_x")
+			if err == nil {
+				t.Fatal("expected error for rate-limit")
+			}
+			if errs.IsTyped(err) {
+				t.Errorf("rate-limit must be UNTYPED (transient), got typed %T %v", err, err)
+			}
+		})
+	}
+}
+
+// Non-2xx HTTP with a non-JSON body is ambiguous (not a structured OAuth
+// rejection) — it must stay UNTYPED so a probe caller treats it as upstream
+// noise and stays silent.
 func TestFetchTAT_HTTPNon200_Untyped(t *testing.T) {
 	for _, code := range []int{401, 403, 500, 503} {
 		rt := &stubRoundTripper{respCode: code, respBody: `whatever`}
@@ -182,12 +254,12 @@ func TestFetchTAT_BrandRouting(t *testing.T) {
 		brand   core.LarkBrand
 		wantURL string
 	}{
-		{core.BrandFeishu, "https://open.feishu.cn/open-apis/auth/v3/tenant_access_token/internal"},
-		{core.BrandLark, "https://open.larksuite.com/open-apis/auth/v3/tenant_access_token/internal"},
+		{core.BrandFeishu, "https://accounts.feishu.cn/oauth/v3/token"},
+		{core.BrandLark, "https://accounts.larksuite.com/oauth/v3/token"},
 	}
 	for _, tc := range tests {
 		t.Run(string(tc.brand), func(t *testing.T) {
-			rt := &stubRoundTripper{respCode: 200, respBody: `{"code":0,"tenant_access_token":"t"}`}
+			rt := &stubRoundTripper{respCode: 200, respBody: `{"code":0,"access_token":"t","token_type":"Bearer"}`}
 			hc := &http.Client{Transport: rt}
 			if _, err := FetchTAT(context.Background(), hc, tc.brand, "a", "b"); err != nil {
 				t.Fatal(err)

internal/errclass/codemeta.go

@@ -65,7 +65,7 @@ var codeMeta = map[int]CodeMeta{
 
 	// CategoryConfig
 	99991543: {Category: errs.CategoryConfig, Subtype: errs.SubtypeInvalidClient}, // RFC 6749 §5.2 — app_id / app_secret incorrect (Open API)
-	10014:    {Category: errs.CategoryConfig, Subtype: errs.SubtypeInvalidClient}, // TAT endpoint — "app secret invalid" (TAT-mint variant of 99991543)
+	10014:    {Category: errs.CategoryConfig, Subtype: errs.SubtypeInvalidClient}, // legacy TAT endpoint — "app secret invalid" (pre-v3 variant of 99991543; CLI now reports invalid_client)
 
 	// CategoryPolicy
 	21000: {Category: errs.CategoryPolicy, Subtype: errs.SubtypeChallengeRequired},

internal/output/lark_errors.go

@@ -35,9 +35,12 @@ const (
 	LarkErrAppNotInUse     = 99991662 // app is disabled in this tenant
 	LarkErrAppUnauthorized = 99991673 // app status unavailable; check installation
 
-	// TAT-endpoint variant of the "wrong app credentials" condition.
-	// /open-apis/auth/v3/tenant_access_token/internal returns code 10014
-	// ("app secret invalid") instead of 99991543 when the secret is wrong.
+	// "Wrong app credentials" code from the LEGACY TAT endpoint
+	// (/open-apis/auth/v3/tenant_access_token/internal returns 10014, "app secret
+	// invalid", instead of 99991543). Since the OAuth v3 migration the CLI mints
+	// TAT via accounts/oauth/v3/token and reports this as the OAuth invalid_client
+	// error, so it no longer emits 10014 itself; the constant + codemeta mapping
+	// are retained as a defensive fallback should 10014 still arrive.
 	LarkErrTATInvalidSecret = 10014
 
 	// Rate limit.