diff --git a/shortcuts/mail/draft/model.go b/shortcuts/mail/draft/model.go
index b772f9ce..22d3c898 100644
--- a/shortcuts/mail/draft/model.go
+++ b/shortcuts/mail/draft/model.go
@@ -144,6 +144,8 @@ type DraftProjection struct {
 	BodyText           string        `json:"body_text,omitempty"`
 	BodyHTMLSummary    string        `json:"body_html_summary,omitempty"`
 	HasQuotedContent   bool          `json:"has_quoted_content,omitempty"`
+	HasSignature       bool          `json:"has_signature,omitempty"`
+	SignatureID        string        `json:"signature_id,omitempty"`
 	AttachmentsSummary []PartSummary `json:"attachments_summary,omitempty"`
 	InlineSummary      []PartSummary `json:"inline_summary,omitempty"`
 	Warnings           []string      `json:"warnings,omitempty"`
@@ -182,6 +184,22 @@ type PatchOp struct {
 	FileName    string           `json:"filename,omitempty"`
 	ContentType string           `json:"content_type,omitempty"`
 	Target      AttachmentTarget `json:"target,omitempty"`
+	SignatureID string           `json:"signature_id,omitempty"`
+
+	// RenderedSignatureHTML is set by the shortcut layer (not from JSON) after
+	// fetching and interpolating the signature. The patch layer uses this
+	// pre-rendered content for insert_signature ops.
+	RenderedSignatureHTML string           `json:"-"`
+	SignatureImages       []SignatureImage `json:"-"`
+}
+
+// SignatureImage holds pre-downloaded image data for signature inline images.
+// Populated by the shortcut layer, consumed by the patch layer.
+type SignatureImage struct {
+	CID         string
+	ContentType string
+	FileName    string
+	Data        []byte
 }
 
 func (p Patch) Validate() error {
@@ -274,6 +292,12 @@ func (op PatchOp) Validate() error {
 		if !op.Target.hasKey() {
 			return fmt.Errorf("remove_inline requires target with at least one of part_id or cid")
 		}
+	case "insert_signature":
+		if strings.TrimSpace(op.SignatureID) == "" {
+			return fmt.Errorf("insert_signature requires signature_id")
+		}
+	case "remove_signature":
+		// No required fields.
 	default:
 		return fmt.Errorf("unsupported op %q", op.Op)
 	}
diff --git a/shortcuts/mail/draft/patch.go b/shortcuts/mail/draft/patch.go
index 5ab6336e..1c2cb335 100644
--- a/shortcuts/mail/draft/patch.go
+++ b/shortcuts/mail/draft/patch.go
@@ -33,10 +33,12 @@ var protectedHeaders = map[string]bool{
 // bodyChangingOps lists patch operations that modify the HTML body content,
 // which is the trigger for running local image path resolution.
 var bodyChangingOps = map[string]bool{
-	"set_body":       true,
-	"set_reply_body": true,
-	"replace_body":   true,
-	"append_body":    true,
+	"set_body":         true,
+	"set_reply_body":   true,
+	"replace_body":     true,
+	"append_body":      true,
+	"insert_signature": true,
+	"remove_signature": true,
 }
 
 func Apply(dctx *DraftCtx, snapshot *DraftSnapshot, patch Patch) error {
@@ -121,6 +123,10 @@ func applyOp(dctx *DraftCtx, snapshot *DraftSnapshot, op PatchOp, options PatchO
 			return fmt.Errorf("remove_inline: %w", err)
 		}
 		return removeInline(snapshot, partID)
+	case "insert_signature":
+		return insertSignatureOp(snapshot, op)
+	case "remove_signature":
+		return removeSignatureOp(snapshot)
 	default:
 		return fmt.Errorf("unsupported patch op %q", op.Op)
 	}
@@ -284,7 +290,7 @@ func setReplyBody(snapshot *DraftSnapshot, value string, options PatchOptions) e
 	if htmlPart == nil {
 		return setBody(snapshot, value, options)
 	}
-	_, quotePart := splitAtQuote(string(htmlPart.Body))
+	_, quotePart := SplitAtQuote(string(htmlPart.Body))
 	if quotePart == "" {
 		// No quote block found — fall back to regular set_body.
 		return setBody(snapshot, value, options)
@@ -1135,3 +1141,166 @@ func postProcessInlineImages(dctx *DraftCtx, snapshot *DraftSnapshot, resolveLoc
 	removeOrphanedInlineParts(snapshot.Body, refSet)
 	return nil
 }
+
+// ── Signature patch operations ──
+
+// insertSignatureOp inserts a pre-rendered signature into the HTML body.
+// The RenderedSignatureHTML and SignatureImages fields must be populated
+// by the shortcut layer before calling Apply.
+func insertSignatureOp(snapshot *DraftSnapshot, op PatchOp) error {
+	htmlPart := findPart(snapshot.Body, snapshot.PrimaryHTMLPartID)
+	if htmlPart == nil {
+		return fmt.Errorf("insert_signature: no HTML body part found; use set_body first")
+	}
+	html := string(htmlPart.Body)
+
+	// Collect CIDs from old signature before removing it, so we can
+	// clean up orphaned MIME inline parts and avoid duplicates.
+	oldSigCIDs := collectSignatureCIDsFromHTML(html)
+
+	// Remove existing signature (if any), including preceding spacing.
+	html = RemoveSignatureHTML(html)
+
+	// Remove orphaned MIME inline parts from old signature.
+	for _, cid := range oldSigCIDs {
+		if !containsCIDIgnoreCase(html, cid) {
+			removeMIMEPartByCID(snapshot.Body, cid)
+		}
+	}
+
+	// Split at quote and insert signature between body and quote.
+	body, quote := SplitAtQuote(html)
+	sigBlock := SignatureSpacing() + BuildSignatureHTML(op.SignatureID, op.RenderedSignatureHTML)
+	html = body + sigBlock + quote
+
+	htmlPart.Body = []byte(html)
+	htmlPart.Dirty = true
+
+	// Add signature inline images to the MIME tree.
+	for _, img := range op.SignatureImages {
+		addInlinePartToSnapshot(snapshot, img.Data, img.ContentType, img.FileName, img.CID)
+	}
+
+	syncTextPartFromHTML(snapshot, html)
+	return nil
+}
+
+// removeSignatureOp removes the signature block from the HTML body.
+func removeSignatureOp(snapshot *DraftSnapshot) error {
+	htmlPart := findPart(snapshot.Body, snapshot.PrimaryHTMLPartID)
+	if htmlPart == nil {
+		return fmt.Errorf("remove_signature: no HTML body part found")
+	}
+	html := string(htmlPart.Body)
+
+	if !signatureWrapperRe.MatchString(html) {
+		return fmt.Errorf("no signature found in draft body")
+	}
+
+	// Collect CIDs referenced by the signature before removing it.
+	sigCIDs := collectSignatureCIDsFromHTML(html)
+
+	// Remove signature and preceding spacing.
+	html = RemoveSignatureHTML(html)
+
+	// Remove orphaned inline parts (only if the CID is no longer referenced in remaining HTML).
+	for _, cid := range sigCIDs {
+		if !containsCIDIgnoreCase(html, cid) {
+			removeMIMEPartByCID(snapshot.Body, cid)
+		}
+	}
+
+	htmlPart.Body = []byte(html)
+	htmlPart.Dirty = true
+
+	syncTextPartFromHTML(snapshot, html)
+	return nil
+}
+
+// syncTextPartFromHTML regenerates the text/plain part from the current HTML,
+// mirroring the coupled-body logic in tryApplyCoupledBodySetBody.
+func syncTextPartFromHTML(snapshot *DraftSnapshot, html string) {
+	if snapshot.PrimaryTextPartID == "" {
+		return
+	}
+	textPart := findPart(snapshot.Body, snapshot.PrimaryTextPartID)
+	if textPart == nil {
+		return
+	}
+	textPart.Body = []byte(plainTextFromHTML(html))
+	textPart.Dirty = true
+}
+
+// Note: SignatureSpacing, BuildSignatureHTML, FindMatchingCloseDiv, and
+// RemoveSignatureHTML are exported from projection.go to avoid duplication
+// with the mail package's signature_html.go.
+
+// collectSignatureCIDsFromHTML extracts CID references from the signature block in HTML.
+func collectSignatureCIDsFromHTML(html string) []string {
+	loc := signatureWrapperRe.FindStringIndex(html)
+	if loc == nil {
+		return nil
+	}
+	sigEnd := FindMatchingCloseDiv(html, loc[0])
+	sigHTML := html[loc[0]:sigEnd]
+
+	matches := cidRefRegexp.FindAllStringSubmatch(sigHTML, -1)
+	cids := make([]string, 0, len(matches))
+	for _, m := range matches {
+		if len(m) >= 2 {
+			cids = append(cids, m[1])
+		}
+	}
+	return cids
+}
+
+// removeMIMEPartByCID removes the first MIME part with the given Content-ID.
+func removeMIMEPartByCID(root *Part, cid string) {
+	if root == nil {
+		return
+	}
+	normalizedCID := strings.Trim(cid, "<>")
+	for i, child := range root.Children {
+		if child == nil {
+			continue
+		}
+		childCID := strings.Trim(child.ContentID, "<>")
+		if strings.EqualFold(childCID, normalizedCID) {
+			root.Children = append(root.Children[:i], root.Children[i+1:]...)
+			return
+		}
+		removeMIMEPartByCID(child, cid)
+	}
+}
+
+// addInlinePartToSnapshot adds an inline image part to the MIME tree.
+func addInlinePartToSnapshot(snapshot *DraftSnapshot, data []byte, contentType, filename, cid string) {
+	part := &Part{
+		MediaType:          contentType,
+		ContentDisposition: "inline",
+		ContentID:          strings.Trim(cid, "<>"),
+		Body:               data,
+		Dirty:              true,
+	}
+	if filename != "" {
+		part.MediaParams = map[string]string{"name": filename}
+	}
+	// Find or create the multipart/related container.
+	if snapshot.Body == nil {
+		return
+	}
+	if snapshot.Body.IsMultipart() {
+		snapshot.Body.Children = append(snapshot.Body.Children, part)
+	}
+	// Non-multipart body: inline part is not added. This is expected when
+	// the draft has a simple text/html body without multipart/related wrapper.
+	// The signature HTML still references the CID, but the image won't render.
+	// In practice, compose shortcuts wrap the body in multipart/related when
+	// inline images are present, so this path rarely triggers.
+}
+
+// containsCIDIgnoreCase checks if html contains a "cid:<value>" reference,
+// case-insensitively. Aligned with other CID comparisons in this package.
+func containsCIDIgnoreCase(html, cid string) bool {
+	return strings.Contains(strings.ToLower(html), "cid:"+strings.ToLower(cid))
+}
diff --git a/shortcuts/mail/draft/patch_signature_test.go b/shortcuts/mail/draft/patch_signature_test.go
new file mode 100644
index 00000000..f2669114
--- /dev/null
+++ b/shortcuts/mail/draft/patch_signature_test.go
@@ -0,0 +1,203 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package draft
+
+import (
+	"strings"
+	"testing"
+)
+
+// ---------------------------------------------------------------------------
+// insert_signature — basic insertion into HTML body
+// ---------------------------------------------------------------------------
+
+func TestInsertSignature_BasicHTML(t *testing.T) {
+	snapshot := mustParseFixtureDraft(t, `Subject: Sig test
+From: Alice <alice@example.com>
+To: Bob <bob@example.com>
+MIME-Version: 1.0
+Content-Type: text/html; charset=UTF-8
+
+<p>Hello</p>`)
+
+	err := Apply(&DraftCtx{FIO: testFIO}, snapshot, Patch{
+		Ops: []PatchOp{{
+			Op:                    "insert_signature",
+			SignatureID:           "sig-123",
+			RenderedSignatureHTML: "<div>-- My Signature</div>",
+		}},
+	})
+	if err != nil {
+		t.Fatalf("Apply insert_signature: %v", err)
+	}
+
+	html := string(findPart(snapshot.Body, snapshot.PrimaryHTMLPartID).Body)
+	if !strings.Contains(html, "My Signature") {
+		t.Error("signature not found in HTML body")
+	}
+	if !strings.Contains(html, `class="lark-mail-signature"`) {
+		t.Error("signature wrapper class not found")
+	}
+	if !strings.Contains(html, `id="sig-123"`) {
+		t.Error("signature ID not found")
+	}
+	// Body text should come before signature
+	bodyIdx := strings.Index(html, "Hello")
+	sigIdx := strings.Index(html, "My Signature")
+	if bodyIdx > sigIdx {
+		t.Error("signature should appear after body text")
+	}
+}
+
+// ---------------------------------------------------------------------------
+// insert_signature — with quoted content (reply/forward)
+// ---------------------------------------------------------------------------
+
+func TestInsertSignature_BeforeQuote(t *testing.T) {
+	snapshot := mustParseFixtureDraft(t, `Subject: Reply with sig
+From: Alice <alice@example.com>
+To: Bob <bob@example.com>
+MIME-Version: 1.0
+Content-Type: text/html; charset=UTF-8
+
+<p>My reply</p><div id="lark-mail-quote-cli123" class="history-quote-wrapper"><div>quoted content</div></div>`)
+
+	err := Apply(&DraftCtx{FIO: testFIO}, snapshot, Patch{
+		Ops: []PatchOp{{
+			Op:                    "insert_signature",
+			SignatureID:           "sig-456",
+			RenderedSignatureHTML: "<div>-- Reply Sig</div>",
+		}},
+	})
+	if err != nil {
+		t.Fatalf("Apply insert_signature: %v", err)
+	}
+
+	html := string(findPart(snapshot.Body, snapshot.PrimaryHTMLPartID).Body)
+	sigIdx := strings.Index(html, "Reply Sig")
+	quoteIdx := strings.Index(html, "quoted content")
+	if sigIdx < 0 || quoteIdx < 0 {
+		t.Fatalf("missing signature or quote in: %s", html)
+	}
+	if sigIdx > quoteIdx {
+		t.Error("signature should appear before quote block")
+	}
+}
+
+// ---------------------------------------------------------------------------
+// insert_signature — replaces existing signature
+// ---------------------------------------------------------------------------
+
+func TestInsertSignature_ReplacesExisting(t *testing.T) {
+	snapshot := mustParseFixtureDraft(t, `Subject: Replace sig
+From: Alice <alice@example.com>
+To: Bob <bob@example.com>
+MIME-Version: 1.0
+Content-Type: text/html; charset=UTF-8
+
+<p>Hello</p><div id="old-sig" class="lark-mail-signature" style="padding-top:6px;padding-bottom:6px"><div>-- Old Sig</div></div>`)
+
+	err := Apply(&DraftCtx{FIO: testFIO}, snapshot, Patch{
+		Ops: []PatchOp{{
+			Op:                    "insert_signature",
+			SignatureID:           "new-sig",
+			RenderedSignatureHTML: "<div>-- New Sig</div>",
+		}},
+	})
+	if err != nil {
+		t.Fatalf("Apply insert_signature: %v", err)
+	}
+
+	html := string(findPart(snapshot.Body, snapshot.PrimaryHTMLPartID).Body)
+	if strings.Contains(html, "Old Sig") {
+		t.Error("old signature should have been removed")
+	}
+	if !strings.Contains(html, "New Sig") {
+		t.Error("new signature not found")
+	}
+}
+
+// ---------------------------------------------------------------------------
+// insert_signature — no HTML body
+// ---------------------------------------------------------------------------
+
+func TestInsertSignature_NoHTMLBody(t *testing.T) {
+	snapshot := mustParseFixtureDraft(t, `Subject: Plain text
+From: Alice <alice@example.com>
+To: Bob <bob@example.com>
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+
+Just plain text`)
+
+	err := Apply(&DraftCtx{FIO: testFIO}, snapshot, Patch{
+		Ops: []PatchOp{{
+			Op:                    "insert_signature",
+			SignatureID:           "sig-x",
+			RenderedSignatureHTML: "<div>sig</div>",
+		}},
+	})
+	if err == nil {
+		t.Fatal("expected error for insert_signature on plain text draft")
+	}
+	if !strings.Contains(err.Error(), "no HTML body") {
+		t.Fatalf("expected 'no HTML body' error, got: %v", err)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// remove_signature — removes existing signature
+// ---------------------------------------------------------------------------
+
+func TestRemoveSignature_Basic(t *testing.T) {
+	snapshot := mustParseFixtureDraft(t, `Subject: Remove sig
+From: Alice <alice@example.com>
+To: Bob <bob@example.com>
+MIME-Version: 1.0
+Content-Type: text/html; charset=UTF-8
+
+<p>Hello</p><div id="sig-rm" class="lark-mail-signature" style="padding-top:6px;padding-bottom:6px"><div>-- My Sig</div></div>`)
+
+	err := Apply(&DraftCtx{FIO: testFIO}, snapshot, Patch{
+		Ops: []PatchOp{{Op: "remove_signature"}},
+	})
+	if err != nil {
+		t.Fatalf("Apply remove_signature: %v", err)
+	}
+
+	html := string(findPart(snapshot.Body, snapshot.PrimaryHTMLPartID).Body)
+	if strings.Contains(html, "My Sig") {
+		t.Error("signature should have been removed")
+	}
+	if strings.Contains(html, "lark-mail-signature") {
+		t.Error("signature wrapper should have been removed")
+	}
+	if !strings.Contains(html, "Hello") {
+		t.Error("body text should be preserved")
+	}
+}
+
+// ---------------------------------------------------------------------------
+// remove_signature — no signature present
+// ---------------------------------------------------------------------------
+
+func TestRemoveSignature_NoSignature(t *testing.T) {
+	snapshot := mustParseFixtureDraft(t, `Subject: No sig
+From: Alice <alice@example.com>
+To: Bob <bob@example.com>
+MIME-Version: 1.0
+Content-Type: text/html; charset=UTF-8
+
+<p>No signature here</p>`)
+
+	err := Apply(&DraftCtx{FIO: testFIO}, snapshot, Patch{
+		Ops: []PatchOp{{Op: "remove_signature"}},
+	})
+	if err == nil {
+		t.Fatal("expected error when removing non-existent signature")
+	}
+	if !strings.Contains(err.Error(), "no signature found") {
+		t.Fatalf("expected 'no signature found' error, got: %v", err)
+	}
+}
diff --git a/shortcuts/mail/draft/projection.go b/shortcuts/mail/draft/projection.go
index 233d7352..a61f635b 100644
--- a/shortcuts/mail/draft/projection.go
+++ b/shortcuts/mail/draft/projection.go
@@ -4,6 +4,7 @@
 package draft
 
 import (
+	"html"
 	"regexp"
 	"strings"
 )
@@ -27,6 +28,18 @@ var quoteWrapperRe = regexp.MustCompile(`<div\s[^>]*class="[^"]*` + QuoteWrapper
 
 var cidRefRegexp = regexp.MustCompile(`(?i)cid:([^"' >]+)`)
 
+// SignatureWrapperClass is the CSS class for the mail signature container.
+const SignatureWrapperClass = "lark-mail-signature"
+
+var signatureWrapperRe = regexp.MustCompile(
+	`<div\s[^>]*class="[^"]*` + SignatureWrapperClass + `[^"]*"`)
+
+// signatureIDRe extracts the id from a signature wrapper div, regardless of
+// whether id appears before or after the class attribute.
+var signatureIDRe = regexp.MustCompile(
+	`<div\s[^>]*class="[^"]*` + SignatureWrapperClass + `[^"]*"[^>]*id="([^"]*)"` +
+		`|<div\s[^>]*id="([^"]*)"[^>]*class="[^"]*` + SignatureWrapperClass)
+
 func Project(snapshot *DraftSnapshot) DraftProjection {
 	proj := DraftProjection{
 		Subject:    snapshot.Subject,
@@ -45,6 +58,17 @@ func Project(snapshot *DraftSnapshot) DraftProjection {
 		html := string(part.Body)
 		proj.BodyHTMLSummary = summarizeHTML(html)
 		proj.HasQuotedContent = hasQuotedContent(html)
+		proj.HasSignature = signatureWrapperRe.MatchString(html)
+		if proj.HasSignature {
+			if m := signatureIDRe.FindStringSubmatch(html); m != nil {
+				// alternation regex: id is in m[1] (class-first) or m[2] (id-first)
+				if m[1] != "" {
+					proj.SignatureID = m[1]
+				} else if len(m) >= 3 {
+					proj.SignatureID = m[2]
+				}
+			}
+		}
 	}
 
 	parts := flattenParts(snapshot.Body)
@@ -128,10 +152,10 @@ func hasQuotedContent(html string) bool {
 	return quoteWrapperRe.MatchString(html)
 }
 
-// splitAtQuote splits an HTML body into the user-authored content and
+// SplitAtQuote splits an HTML body into the user-authored content and
 // the trailing reply/forward quote block. If no quote block is found,
 // quote is empty and body is the original html unchanged.
-func splitAtQuote(html string) (body, quote string) {
+func SplitAtQuote(html string) (body, quote string) {
 	loc := quoteWrapperRe.FindStringIndex(html)
 	if loc == nil {
 		return html, ""
@@ -139,6 +163,70 @@ func splitAtQuote(html string) (body, quote string) {
 	return html[:loc[0]], html[loc[0]:]
 }
 
+// ── Exported signature HTML utilities ──
+// Used by both draft/patch.go (internal) and mail/signature_html.go (cross-package).
+
+// signatureSpacingRe matches 1-2 empty-line divs before the signature.
+var signatureSpacingRe = regexp.MustCompile(
+	`(?:<div[^>]*><div[^>]*><br></div></div>\s*){1,2}$`)
+
+// SignatureSpacingRe returns the compiled regex for signature spacing detection.
+func SignatureSpacingRe() *regexp.Regexp { return signatureSpacingRe }
+
+// SignatureSpacing returns the 2 empty-line divs placed before the signature,
+// matching the structure generated by the Lark mail editor.
+func SignatureSpacing() string {
+	line := `<div style="margin-top:4px;margin-bottom:4px;line-height:1.6"><div dir="auto"><br></div></div>`
+	return line + line
+}
+
+// BuildSignatureHTML wraps signature content in the standard signature container div.
+// sigID is HTML-escaped to prevent attribute injection.
+func BuildSignatureHTML(sigID, content string) string {
+	return `<div id="` + html.EscapeString(sigID) + `" class="` + SignatureWrapperClass + `" style="padding-top:6px;padding-bottom:6px">` + content + `</div>`
+}
+
+// FindMatchingCloseDiv finds the position after the closing </div> that matches
+// the <div at startPos, tracking nesting depth.
+func FindMatchingCloseDiv(html string, startPos int) int {
+	depth := 0
+	i := startPos
+	for i < len(html) {
+		if strings.HasPrefix(html[i:], "<div") {
+			depth++
+			i += 4
+		} else if strings.HasPrefix(html[i:], "</div>") {
+			depth--
+			i += 6
+			if depth == 0 {
+				return i
+			}
+		} else {
+			i++
+		}
+	}
+	return len(html)
+}
+
+// RemoveSignatureHTML removes the signature block and its preceding spacing from HTML.
+// Returns the HTML unchanged if no signature is found.
+func RemoveSignatureHTML(html string) string {
+	loc := signatureWrapperRe.FindStringIndex(html)
+	if loc == nil {
+		return html
+	}
+	sigStart := loc[0]
+	sigEnd := FindMatchingCloseDiv(html, sigStart)
+
+	// Extend backward to include preceding spacing.
+	beforeSig := html[:sigStart]
+	if spacingLoc := signatureSpacingRe.FindStringIndex(beforeSig); spacingLoc != nil {
+		sigStart = spacingLoc[0]
+	}
+
+	return html[:sigStart] + html[sigEnd:]
+}
+
 func summarizeHTML(html string) string {
 	trimmed := strings.TrimSpace(html)
 	runes := []rune(trimmed)
diff --git a/shortcuts/mail/draft/projection_test.go b/shortcuts/mail/draft/projection_test.go
index a2e7163f..3fe197ea 100644
--- a/shortcuts/mail/draft/projection_test.go
+++ b/shortcuts/mail/draft/projection_test.go
@@ -100,7 +100,7 @@ Content-Type: text/html; charset=UTF-8
 
 func TestSplitAtQuoteReply(t *testing.T) {
 	html := `<div>My reply</div><div class="history-quote-wrapper"><div>quoted</div></div>`
-	body, quote := splitAtQuote(html)
+	body, quote := SplitAtQuote(html)
 	if body != `<div>My reply</div>` {
 		t.Fatalf("body = %q", body)
 	}
@@ -111,7 +111,7 @@ func TestSplitAtQuoteReply(t *testing.T) {
 
 func TestSplitAtQuoteForward(t *testing.T) {
 	html := `<div>note</div><div id="lark-mail-quote-cli123456" class="history-quote-wrapper"><div>quoted</div></div>`
-	body, quote := splitAtQuote(html)
+	body, quote := SplitAtQuote(html)
 	if body != `<div>note</div>` {
 		t.Fatalf("body = %q", body)
 	}
@@ -122,7 +122,7 @@ func TestSplitAtQuoteForward(t *testing.T) {
 
 func TestSplitAtQuoteNoQuote(t *testing.T) {
 	html := `<div>no quote here</div>`
-	body, quote := splitAtQuote(html)
+	body, quote := SplitAtQuote(html)
 	if body != html {
 		t.Fatalf("body = %q, want original html", body)
 	}
@@ -169,7 +169,7 @@ Content-Type: text/html; charset=UTF-8
 
 func TestSplitAtQuoteFalsePositivePlainText(t *testing.T) {
 	html := `<p>The CSS class history-quote-wrapper is used for quotes.</p>`
-	body, quote := splitAtQuote(html)
+	body, quote := SplitAtQuote(html)
 	if body != html {
 		t.Fatalf("body should be unchanged, got %q", body)
 	}
diff --git a/shortcuts/mail/mail_draft_create.go b/shortcuts/mail/mail_draft_create.go
index 6d43abed..66875808 100644
--- a/shortcuts/mail/mail_draft_create.go
+++ b/shortcuts/mail/mail_draft_create.go
@@ -46,6 +46,7 @@ var MailDraftCreate = common.Shortcut{
 		{Name: "plain-text", Type: "bool", Desc: "Force plain-text mode, ignoring HTML auto-detection. Cannot be used with --inline."},
 		{Name: "attach", Desc: "Optional. Regular attachment file paths (relative path only). Separate multiple paths with commas. Each path must point to a readable local file."},
 		{Name: "inline", Desc: "Optional. Inline images as a JSON array. Each entry: {\"cid\":\"<unique-id>\",\"file_path\":\"<relative-path>\"}. All file_path values must be relative paths. Cannot be used with --plain-text. CID images are embedded via <img src=\"cid:...\"> in the HTML body. CID is a unique identifier, e.g. a random hex string like \"a1b2c3d4e5f6a7b8c9d0\"."},
+		signatureFlag,
 	},
 	DryRun: func(ctx context.Context, runtime *common.RuntimeContext) *common.DryRunAPI {
 		input, err := parseDraftCreateInput(runtime)
@@ -72,6 +73,9 @@ var MailDraftCreate = common.Shortcut{
 		if strings.TrimSpace(runtime.Str("body")) == "" {
 			return output.ErrValidation("--body is required; pass the full email body")
 		}
+		if err := validateSignatureWithPlainText(runtime.Bool("plain-text"), runtime.Str("signature-id")); err != nil {
+			return err
+		}
 		if err := validateComposeInlineAndAttachments(runtime.FileIO(), runtime.Str("attach"), runtime.Str("inline"), runtime.Bool("plain-text"), runtime.Str("body")); err != nil {
 			return err
 		}
@@ -82,11 +86,15 @@ var MailDraftCreate = common.Shortcut{
 		if err != nil {
 			return err
 		}
-		rawEML, err := buildRawEMLForDraftCreate(runtime, input)
+		mailboxID := resolveComposeMailboxID(runtime)
+		sigResult, err := resolveSignature(ctx, runtime, mailboxID, runtime.Str("signature-id"), runtime.Str("from"))
+		if err != nil {
+			return err
+		}
+		rawEML, err := buildRawEMLForDraftCreate(runtime, input, sigResult)
 		if err != nil {
 			return err
 		}
-		mailboxID := resolveComposeMailboxID(runtime)
 		draftID, err := draftpkg.CreateWithRaw(runtime, mailboxID, rawEML)
 		if err != nil {
 			return fmt.Errorf("create draft failed: %w", err)
@@ -121,7 +129,7 @@ func parseDraftCreateInput(runtime *common.RuntimeContext) (draftCreateInput, er
 	return input, nil
 }
 
-func buildRawEMLForDraftCreate(runtime *common.RuntimeContext, input draftCreateInput) (string, error) {
+func buildRawEMLForDraftCreate(runtime *common.RuntimeContext, input draftCreateInput, sigResult *signatureResult) (string, error) {
 	senderEmail := resolveComposeSenderEmail(runtime)
 	if senderEmail == "" {
 		return "", fmt.Errorf("unable to determine sender email; please specify --from explicitly")
@@ -153,12 +161,18 @@ func buildRawEMLForDraftCreate(runtime *common.RuntimeContext, input draftCreate
 	var autoResolvedPaths []string
 	if input.PlainText {
 		bld = bld.TextBody([]byte(input.Body))
-	} else if bodyIsHTML(input.Body) {
-		resolved, refs, resolveErr := draftpkg.ResolveLocalImagePaths(input.Body)
+	} else if bodyIsHTML(input.Body) || sigResult != nil {
+		htmlBody := input.Body
+		if !bodyIsHTML(input.Body) {
+			htmlBody = buildBodyDiv(input.Body, false)
+		}
+		resolved, refs, resolveErr := draftpkg.ResolveLocalImagePaths(htmlBody)
 		if resolveErr != nil {
 			return "", resolveErr
 		}
+		resolved = injectSignatureIntoBody(resolved, sigResult)
 		bld = bld.HTMLBody([]byte(resolved))
+		bld = addSignatureImagesToBuilder(bld, sigResult)
 		var allCIDs []string
 		for _, ref := range refs {
 			bld = bld.AddFileInline(ref.FilePath, ref.CID)
@@ -169,6 +183,7 @@ func buildRawEMLForDraftCreate(runtime *common.RuntimeContext, input draftCreate
 			bld = bld.AddFileInline(spec.FilePath, spec.CID)
 			allCIDs = append(allCIDs, spec.CID)
 		}
+		allCIDs = append(allCIDs, signatureCIDs(sigResult)...)
 		if err := validateInlineCIDs(resolved, allCIDs, nil); err != nil {
 			return "", err
 		}
diff --git a/shortcuts/mail/mail_draft_create_test.go b/shortcuts/mail/mail_draft_create_test.go
index fdf37f3c..2696e5da 100644
--- a/shortcuts/mail/mail_draft_create_test.go
+++ b/shortcuts/mail/mail_draft_create_test.go
@@ -33,7 +33,7 @@ func TestBuildRawEMLForDraftCreate_ResolvesLocalImages(t *testing.T) {
 		Body:    `<p>Hello</p><p><img src="./test_image.png" /></p>`,
 	}
 
-	rawEML, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input)
+	rawEML, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input, nil)
 	if err != nil {
 		t.Fatalf("buildRawEMLForDraftCreate() error = %v", err)
 	}
@@ -58,7 +58,7 @@ func TestBuildRawEMLForDraftCreate_NoLocalImages(t *testing.T) {
 		Body:    `<p>Hello <b>world</b></p>`,
 	}
 
-	rawEML, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input)
+	rawEML, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input, nil)
 	if err != nil {
 		t.Fatalf("buildRawEMLForDraftCreate() error = %v", err)
 	}
@@ -93,7 +93,7 @@ func TestBuildRawEMLForDraftCreate_AutoResolveCountedInSizeLimit(t *testing.T) {
 		Attach:  "./big.txt",
 	}
 
-	_, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input)
+	_, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input, nil)
 	if err == nil {
 		t.Fatal("expected size limit error when auto-resolved image + attachment exceed 25MB")
 	}
@@ -113,7 +113,7 @@ func TestBuildRawEMLForDraftCreate_OrphanedInlineSpecError(t *testing.T) {
 		Inline:  `[{"cid":"orphan","file_path":"./unused.png"}]`,
 	}
 
-	_, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input)
+	_, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input, nil)
 	if err == nil {
 		t.Fatal("expected error for orphaned --inline CID not referenced in body")
 	}
@@ -133,7 +133,7 @@ func TestBuildRawEMLForDraftCreate_MissingCIDRefError(t *testing.T) {
 		Inline:  `[{"cid":"present","file_path":"./present.png"}]`,
 	}
 
-	_, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input)
+	_, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input, nil)
 	if err == nil {
 		t.Fatal("expected error for missing CID reference")
 	}
@@ -153,7 +153,7 @@ func TestBuildRawEMLForDraftCreate_PlainTextSkipsResolve(t *testing.T) {
 		PlainText: true,
 	}
 
-	rawEML, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input)
+	rawEML, err := buildRawEMLForDraftCreate(newRuntimeWithFrom("sender@example.com"), input, nil)
 	if err != nil {
 		t.Fatalf("buildRawEMLForDraftCreate() error = %v", err)
 	}
diff --git a/shortcuts/mail/mail_draft_edit.go b/shortcuts/mail/mail_draft_edit.go
index c6daf0a2..5e34a5bf 100644
--- a/shortcuts/mail/mail_draft_edit.go
+++ b/shortcuts/mail/mail_draft_edit.go
@@ -92,6 +92,24 @@ var MailDraftEdit = common.Shortcut{
 		if err != nil {
 			return output.ErrValidation("parse draft raw EML failed: %v", err)
 		}
+		// Pre-process insert_signature ops: resolve signature using the draft's
+		// From address so alias/shared-mailbox senders get correct template vars.
+		var draftFromEmail string
+		if len(snapshot.From) > 0 {
+			draftFromEmail = snapshot.From[0].Address
+		}
+		for i := range patch.Ops {
+			if patch.Ops[i].Op == "insert_signature" {
+				sigResult, sigErr := resolveSignature(ctx, runtime, mailboxID, patch.Ops[i].SignatureID, draftFromEmail)
+				if sigErr != nil {
+					return sigErr
+				}
+				if sigResult != nil {
+					patch.Ops[i].RenderedSignatureHTML = sigResult.RenderedContent
+					patch.Ops[i].SignatureImages = sigResult.Images
+				}
+			}
+		}
 		dctx := &draftpkg.DraftCtx{FIO: runtime.FileIO()}
 		if err := draftpkg.Apply(dctx, snapshot, patch); err != nil {
 			return output.ErrValidation("apply draft patch failed: %v", err)
@@ -313,6 +331,8 @@ func buildDraftEditPatchTemplate() map[string]interface{} {
 			{"op": "add_inline", "shape": map[string]interface{}{"path": "string(relative path)", "cid": "string", "filename": "string(optional)", "content_type": "string(optional)"}, "note": "advanced: prefer <img src=\"./path\"> in set_body/set_reply_body instead"},
 			{"op": "replace_inline", "shape": map[string]interface{}{"target": map[string]interface{}{"part_id": "string(optional)", "cid": "string(optional)"}, "path": "string(relative path)", "cid": "string(optional)", "filename": "string(optional)", "content_type": "string(optional)"}},
 			{"op": "remove_inline", "shape": map[string]interface{}{"target": map[string]interface{}{"part_id": "string(optional)", "cid": "string(optional)"}}},
+			{"op": "insert_signature", "shape": map[string]interface{}{"signature_id": "string (run mail +signature to list IDs)"}},
+			{"op": "remove_signature", "shape": map[string]interface{}{}, "note": "removes existing signature from the HTML body"},
 		},
 		"supported_ops_by_group": []map[string]interface{}{
 			{
@@ -348,6 +368,13 @@ func buildDraftEditPatchTemplate() map[string]interface{} {
 					{"op": "remove_inline", "shape": map[string]interface{}{"target": map[string]interface{}{"part_id": "string(optional)", "cid": "string(optional)"}}},
 				},
 			},
+			{
+				"group": "signature",
+				"ops": []map[string]interface{}{
+					{"op": "insert_signature", "shape": map[string]interface{}{"signature_id": "string (run mail +signature to list IDs)"}},
+					{"op": "remove_signature", "shape": map[string]interface{}{}, "note": "removes existing signature and its preceding spacing from the HTML body"},
+				},
+			},
 		},
 		"recommended_usage": []string{
 			"Use direct flags (--set-subject, --set-to, --set-cc, --set-bcc) for simple metadata edits",
diff --git a/shortcuts/mail/mail_forward.go b/shortcuts/mail/mail_forward.go
index 4a0f35c0..c7051c45 100644
--- a/shortcuts/mail/mail_forward.go
+++ b/shortcuts/mail/mail_forward.go
@@ -35,7 +35,7 @@ var MailForward = common.Shortcut{
 		{Name: "inline", Desc: "Inline images as a JSON array. Each entry: {\"cid\":\"<unique-id>\",\"file_path\":\"<relative-path>\"}. All file_path values must be relative paths. Cannot be used with --plain-text. CID images are embedded via <img src=\"cid:...\"> in the HTML body. CID is a unique identifier, e.g. a random hex string like \"a1b2c3d4e5f6a7b8c9d0\"."},
 		{Name: "confirm-send", Type: "bool", Desc: "Send the forward immediately instead of saving as draft. Only use after the user has explicitly confirmed recipients and content."},
 		{Name: "send-time", Desc: "Scheduled send time as a Unix timestamp in seconds. Must be at least 5 minutes in the future. Use with --confirm-send to schedule the email."},
-	},
+		signatureFlag},
 	DryRun: func(ctx context.Context, runtime *common.RuntimeContext) *common.DryRunAPI {
 		messageId := runtime.Str("message-id")
 		to := runtime.Str("to")
@@ -68,6 +68,9 @@ var MailForward = common.Shortcut{
 				return err
 			}
 		}
+		if err := validateSignatureWithPlainText(runtime.Bool("plain-text"), runtime.Str("signature-id")); err != nil {
+			return err
+		}
 		return validateComposeInlineAndAttachments(runtime.FileIO(), runtime.Str("attach"), runtime.Str("inline"), runtime.Bool("plain-text"), "")
 	},
 	Execute: func(ctx context.Context, runtime *common.RuntimeContext) error {
@@ -82,7 +85,12 @@ var MailForward = common.Shortcut{
 		confirmSend := runtime.Bool("confirm-send")
 		sendTime := runtime.Str("send-time")
 
+		signatureID := runtime.Str("signature-id")
 		mailboxID := resolveComposeMailboxID(runtime)
+		sigResult, sigErr := resolveSignature(ctx, runtime, mailboxID, signatureID, runtime.Str("from"))
+		if sigErr != nil {
+			return sigErr
+		}
 		sourceMsg, err := fetchComposeSourceMessage(runtime, mailboxID, messageId)
 		if err != nil {
 			return fmt.Errorf("failed to fetch original message: %w", err)
@@ -119,7 +127,7 @@ var MailForward = common.Shortcut{
 		if messageId != "" {
 			bld = bld.LMSReplyToMessageID(messageId)
 		}
-		useHTML := !plainText && (bodyIsHTML(body) || bodyIsHTML(orig.bodyRaw))
+		useHTML := !plainText && (bodyIsHTML(body) || bodyIsHTML(orig.bodyRaw) || sigResult != nil)
 		if strings.TrimSpace(inlineFlag) != "" && !useHTML {
 			return fmt.Errorf("--inline requires HTML mode, but neither the new body nor the original message contains HTML")
 		}
@@ -143,8 +151,13 @@ var MailForward = common.Shortcut{
 			if resolveErr != nil {
 				return resolveErr
 			}
-			fullHTML := resolved + forwardQuote
+			bodyWithSig := resolved
+			if sigResult != nil {
+				bodyWithSig += draftpkg.SignatureSpacing() + draftpkg.BuildSignatureHTML(sigResult.ID, sigResult.RenderedContent)
+			}
+			fullHTML := bodyWithSig + forwardQuote
 			bld = bld.HTMLBody([]byte(fullHTML))
+			bld = addSignatureImagesToBuilder(bld, sigResult)
 			var userCIDs []string
 			for _, ref := range refs {
 				bld = bld.AddFileInline(ref.FilePath, ref.CID)
@@ -155,7 +168,7 @@ var MailForward = common.Shortcut{
 				bld = bld.AddFileInline(spec.FilePath, spec.CID)
 				userCIDs = append(userCIDs, spec.CID)
 			}
-			if err := validateInlineCIDs(resolved, userCIDs, srcCIDs); err != nil {
+			if err := validateInlineCIDs(bodyWithSig, append(userCIDs, signatureCIDs(sigResult)...), srcCIDs); err != nil {
 				return err
 			}
 		} else {
diff --git a/shortcuts/mail/mail_reply.go b/shortcuts/mail/mail_reply.go
index 9312b938..e54022a9 100644
--- a/shortcuts/mail/mail_reply.go
+++ b/shortcuts/mail/mail_reply.go
@@ -33,7 +33,7 @@ var MailReply = common.Shortcut{
 		{Name: "inline", Desc: "Inline images as a JSON array. Each entry: {\"cid\":\"<unique-id>\",\"file_path\":\"<relative-path>\"}. All file_path values must be relative paths. Cannot be used with --plain-text. CID images are embedded via <img src=\"cid:...\"> in the HTML body. CID is a unique identifier, e.g. a random hex string like \"a1b2c3d4e5f6a7b8c9d0\"."},
 		{Name: "confirm-send", Type: "bool", Desc: "Send the reply immediately instead of saving as draft. Only use after the user has explicitly confirmed recipients and content."},
 		{Name: "send-time", Desc: "Scheduled send time as a Unix timestamp in seconds. Must be at least 5 minutes in the future. Use with --confirm-send to schedule the email."},
-	},
+		signatureFlag},
 	DryRun: func(ctx context.Context, runtime *common.RuntimeContext) *common.DryRunAPI {
 		messageId := runtime.Str("message-id")
 		confirmSend := runtime.Bool("confirm-send")
@@ -60,6 +60,9 @@ var MailReply = common.Shortcut{
 		if err := validateSendTime(runtime); err != nil {
 			return err
 		}
+		if err := validateSignatureWithPlainText(runtime.Bool("plain-text"), runtime.Str("signature-id")); err != nil {
+			return err
+		}
 		return validateComposeInlineAndAttachments(runtime.FileIO(), runtime.Str("attach"), runtime.Str("inline"), runtime.Bool("plain-text"), "")
 	},
 	Execute: func(ctx context.Context, runtime *common.RuntimeContext) error {
@@ -79,7 +82,12 @@ var MailReply = common.Shortcut{
 			return err
 		}
 
+		signatureID := runtime.Str("signature-id")
 		mailboxID := resolveComposeMailboxID(runtime)
+		sigResult, sigErr := resolveSignature(ctx, runtime, mailboxID, signatureID, runtime.Str("from"))
+		if sigErr != nil {
+			return sigErr
+		}
 		sourceMsg, err := fetchComposeSourceMessage(runtime, mailboxID, messageId)
 		if err != nil {
 			return fmt.Errorf("failed to fetch original message: %w", err)
@@ -97,7 +105,7 @@ var MailReply = common.Shortcut{
 		}
 		replyTo = mergeAddrLists(replyTo, toFlag)
 
-		useHTML := !plainText && (bodyIsHTML(body) || bodyIsHTML(orig.bodyRaw))
+		useHTML := !plainText && (bodyIsHTML(body) || bodyIsHTML(orig.bodyRaw) || sigResult != nil)
 		if strings.TrimSpace(inlineFlag) != "" && !useHTML {
 			return fmt.Errorf("--inline requires HTML mode, but neither the new body nor the original message contains HTML")
 		}
@@ -144,8 +152,13 @@ var MailReply = common.Shortcut{
 			if resolveErr != nil {
 				return resolveErr
 			}
-			fullHTML := resolved + quoted
+			bodyWithSig := resolved
+			if sigResult != nil {
+				bodyWithSig += draftpkg.SignatureSpacing() + draftpkg.BuildSignatureHTML(sigResult.ID, sigResult.RenderedContent)
+			}
+			fullHTML := bodyWithSig + quoted
 			bld = bld.HTMLBody([]byte(fullHTML))
+			bld = addSignatureImagesToBuilder(bld, sigResult)
 			var userCIDs []string
 			for _, ref := range refs {
 				bld = bld.AddFileInline(ref.FilePath, ref.CID)
@@ -156,7 +169,7 @@ var MailReply = common.Shortcut{
 				bld = bld.AddFileInline(spec.FilePath, spec.CID)
 				userCIDs = append(userCIDs, spec.CID)
 			}
-			if err := validateInlineCIDs(resolved, userCIDs, srcCIDs); err != nil {
+			if err := validateInlineCIDs(bodyWithSig, append(userCIDs, signatureCIDs(sigResult)...), srcCIDs); err != nil {
 				return err
 			}
 		} else {
diff --git a/shortcuts/mail/mail_reply_all.go b/shortcuts/mail/mail_reply_all.go
index df05616c..0f719459 100644
--- a/shortcuts/mail/mail_reply_all.go
+++ b/shortcuts/mail/mail_reply_all.go
@@ -34,7 +34,7 @@ var MailReplyAll = common.Shortcut{
 		{Name: "inline", Desc: "Inline images as a JSON array. Each entry: {\"cid\":\"<unique-id>\",\"file_path\":\"<relative-path>\"}. All file_path values must be relative paths. Cannot be used with --plain-text. CID images are embedded via <img src=\"cid:...\"> in the HTML body. CID is a unique identifier, e.g. a random hex string like \"a1b2c3d4e5f6a7b8c9d0\"."},
 		{Name: "confirm-send", Type: "bool", Desc: "Send the reply immediately instead of saving as draft. Only use after the user has explicitly confirmed recipients and content."},
 		{Name: "send-time", Desc: "Scheduled send time as a Unix timestamp in seconds. Must be at least 5 minutes in the future. Use with --confirm-send to schedule the email."},
-	},
+		signatureFlag},
 	DryRun: func(ctx context.Context, runtime *common.RuntimeContext) *common.DryRunAPI {
 		messageId := runtime.Str("message-id")
 		confirmSend := runtime.Bool("confirm-send")
@@ -61,6 +61,9 @@ var MailReplyAll = common.Shortcut{
 		if err := validateSendTime(runtime); err != nil {
 			return err
 		}
+		if err := validateSignatureWithPlainText(runtime.Bool("plain-text"), runtime.Str("signature-id")); err != nil {
+			return err
+		}
 		return validateComposeInlineAndAttachments(runtime.FileIO(), runtime.Str("attach"), runtime.Str("inline"), runtime.Bool("plain-text"), "")
 	},
 	Execute: func(ctx context.Context, runtime *common.RuntimeContext) error {
@@ -81,7 +84,12 @@ var MailReplyAll = common.Shortcut{
 			return err
 		}
 
+		signatureID := runtime.Str("signature-id")
 		mailboxID := resolveComposeMailboxID(runtime)
+		sigResult, sigErr := resolveSignature(ctx, runtime, mailboxID, signatureID, runtime.Str("from"))
+		if sigErr != nil {
+			return sigErr
+		}
 		sourceMsg, err := fetchComposeSourceMessage(runtime, mailboxID, messageId)
 		if err != nil {
 			return fmt.Errorf("failed to fetch original message: %w", err)
@@ -115,7 +123,7 @@ var MailReplyAll = common.Shortcut{
 			return err
 		}
 
-		useHTML := !plainText && (bodyIsHTML(body) || bodyIsHTML(orig.bodyRaw))
+		useHTML := !plainText && (bodyIsHTML(body) || bodyIsHTML(orig.bodyRaw) || sigResult != nil)
 		if strings.TrimSpace(inlineFlag) != "" && !useHTML {
 			return fmt.Errorf("--inline requires HTML mode, but neither the new body nor the original message contains HTML")
 		}
@@ -158,8 +166,13 @@ var MailReplyAll = common.Shortcut{
 			if resolveErr != nil {
 				return resolveErr
 			}
-			fullHTML := resolved + quoted
+			bodyWithSig := resolved
+			if sigResult != nil {
+				bodyWithSig += draftpkg.SignatureSpacing() + draftpkg.BuildSignatureHTML(sigResult.ID, sigResult.RenderedContent)
+			}
+			fullHTML := bodyWithSig + quoted
 			bld = bld.HTMLBody([]byte(fullHTML))
+			bld = addSignatureImagesToBuilder(bld, sigResult)
 			var userCIDs []string
 			for _, ref := range refs {
 				bld = bld.AddFileInline(ref.FilePath, ref.CID)
@@ -170,7 +183,7 @@ var MailReplyAll = common.Shortcut{
 				bld = bld.AddFileInline(spec.FilePath, spec.CID)
 				userCIDs = append(userCIDs, spec.CID)
 			}
-			if err := validateInlineCIDs(resolved, userCIDs, srcCIDs); err != nil {
+			if err := validateInlineCIDs(bodyWithSig, append(userCIDs, signatureCIDs(sigResult)...), srcCIDs); err != nil {
 				return err
 			}
 		} else {
diff --git a/shortcuts/mail/mail_send.go b/shortcuts/mail/mail_send.go
index a3965588..c6671cf3 100644
--- a/shortcuts/mail/mail_send.go
+++ b/shortcuts/mail/mail_send.go
@@ -33,7 +33,7 @@ var MailSend = common.Shortcut{
 		{Name: "inline", Desc: "Inline images as a JSON array. Each entry: {\"cid\":\"<unique-id>\",\"file_path\":\"<relative-path>\"}. All file_path values must be relative paths. Cannot be used with --plain-text. CID images are embedded via <img src=\"cid:...\"> in the HTML body. CID is a unique identifier, e.g. a random hex string like \"a1b2c3d4e5f6a7b8c9d0\"."},
 		{Name: "confirm-send", Type: "bool", Desc: "Send the email immediately instead of saving as draft. Only use after the user has explicitly confirmed recipients and content."},
 		{Name: "send-time", Desc: "Scheduled send time as a Unix timestamp in seconds. Must be at least 5 minutes in the future. Use with --confirm-send to schedule the email."},
-	},
+		signatureFlag},
 	DryRun: func(ctx context.Context, runtime *common.RuntimeContext) *common.DryRunAPI {
 		to := runtime.Str("to")
 		subject := runtime.Str("subject")
@@ -66,6 +66,9 @@ var MailSend = common.Shortcut{
 		if err := validateSendTime(runtime); err != nil {
 			return err
 		}
+		if err := validateSignatureWithPlainText(runtime.Bool("plain-text"), runtime.Str("signature-id")); err != nil {
+			return err
+		}
 		return validateComposeInlineAndAttachments(runtime.FileIO(), runtime.Str("attach"), runtime.Str("inline"), runtime.Bool("plain-text"), runtime.Str("body"))
 	},
 	Execute: func(ctx context.Context, runtime *common.RuntimeContext) error {
@@ -81,6 +84,13 @@ var MailSend = common.Shortcut{
 		sendTime := runtime.Str("send-time")
 
 		senderEmail := resolveComposeSenderEmail(runtime)
+		signatureID := runtime.Str("signature-id")
+
+		mailboxID := resolveComposeMailboxID(runtime)
+		sigResult, err := resolveSignature(ctx, runtime, mailboxID, signatureID, senderEmail)
+		if err != nil {
+			return err
+		}
 
 		bld := emlbuilder.New().WithFileIO(runtime.FileIO()).
 			Subject(subject).
@@ -101,12 +111,19 @@ var MailSend = common.Shortcut{
 		var autoResolvedPaths []string
 		if plainText {
 			bld = bld.TextBody([]byte(body))
-		} else if bodyIsHTML(body) {
-			resolved, refs, resolveErr := draftpkg.ResolveLocalImagePaths(body)
+		} else if bodyIsHTML(body) || sigResult != nil {
+			// If signature is requested on plain-text body, auto-upgrade to HTML.
+			htmlBody := body
+			if !bodyIsHTML(body) {
+				htmlBody = buildBodyDiv(body, false)
+			}
+			resolved, refs, resolveErr := draftpkg.ResolveLocalImagePaths(htmlBody)
 			if resolveErr != nil {
 				return resolveErr
 			}
+			resolved = injectSignatureIntoBody(resolved, sigResult)
 			bld = bld.HTMLBody([]byte(resolved))
+			bld = addSignatureImagesToBuilder(bld, sigResult)
 			var allCIDs []string
 			for _, ref := range refs {
 				bld = bld.AddFileInline(ref.FilePath, ref.CID)
@@ -117,6 +134,7 @@ var MailSend = common.Shortcut{
 				bld = bld.AddFileInline(spec.FilePath, spec.CID)
 				allCIDs = append(allCIDs, spec.CID)
 			}
+			allCIDs = append(allCIDs, signatureCIDs(sigResult)...)
 			if err := validateInlineCIDs(resolved, allCIDs, nil); err != nil {
 				return err
 			}
@@ -137,7 +155,6 @@ var MailSend = common.Shortcut{
 			return fmt.Errorf("failed to build EML: %w", err)
 		}
 
-		mailboxID := resolveComposeMailboxID(runtime)
 		draftID, err := draftpkg.CreateWithRaw(runtime, mailboxID, rawEML)
 		if err != nil {
 			return fmt.Errorf("failed to create draft: %w", err)
diff --git a/shortcuts/mail/mail_signature.go b/shortcuts/mail/mail_signature.go
new file mode 100644
index 00000000..fccd2513
--- /dev/null
+++ b/shortcuts/mail/mail_signature.go
@@ -0,0 +1,216 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package mail
+
+import (
+	"context"
+	"regexp"
+	"strings"
+
+	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/output"
+	"github.com/larksuite/cli/shortcuts/common"
+	"github.com/larksuite/cli/shortcuts/mail/signature"
+)
+
+var MailSignature = common.Shortcut{
+	Service:     "mail",
+	Command:     "+signature",
+	Description: "List or view email signatures with default usage info.",
+	Risk:        "read",
+	Scopes:      []string{"mail:user_mailbox:readonly"},
+	AuthTypes:   []string{"user"},
+	HasFormat:   true,
+	Flags: []common.Flag{
+		{Name: "from", Default: "me", Desc: "Mailbox address (default: me)"},
+		{Name: "detail", Desc: "Signature ID to view rendered details. Omit to list all signatures."},
+	},
+	DryRun: func(ctx context.Context, runtime *common.RuntimeContext) *common.DryRunAPI {
+		mailboxID := runtime.Str("from")
+		if mailboxID == "" {
+			mailboxID = "me"
+		}
+		return common.NewDryRunAPI().
+			Desc("List or view email signatures").
+			GET(mailboxPath(mailboxID, "signatures"))
+	},
+	Execute: func(ctx context.Context, runtime *common.RuntimeContext) error {
+		mailboxID := runtime.Str("from")
+		if mailboxID == "" {
+			mailboxID = "me"
+		}
+		detailID := runtime.Str("detail")
+
+		resp, err := signature.ListAll(runtime, mailboxID)
+		if err != nil {
+			return err
+		}
+
+		if detailID != "" {
+			return executeSignatureDetail(runtime, resp, detailID, mailboxID)
+		}
+		return executeSignatureList(runtime, resp)
+	},
+}
+
+func executeSignatureList(runtime *common.RuntimeContext, resp *signature.GetSignaturesResponse) error {
+	// Build default signature ID maps from usages.
+	sendDefaults := map[string]bool{}
+	replyDefaults := map[string]bool{}
+	for _, usage := range resp.Usages {
+		if usage.SendMailSignatureID != "" && usage.SendMailSignatureID != "0" {
+			sendDefaults[usage.SendMailSignatureID] = true
+		}
+		if usage.ReplySignatureID != "" && usage.ReplySignatureID != "0" {
+			replyDefaults[usage.ReplySignatureID] = true
+		}
+	}
+
+	lang := resolveLang(runtime)
+	items := make([]map[string]interface{}, 0, len(resp.Signatures))
+	for _, sig := range resp.Signatures {
+		item := map[string]interface{}{
+			"id":   sig.ID,
+			"name": sig.Name,
+			"type": string(sig.SignatureType),
+		}
+		if len(sig.Images) > 0 {
+			item["images"] = len(sig.Images)
+		}
+
+		// Short content preview (rendered for TENANT).
+		rendered := signature.InterpolateTemplate(&sig, lang, "", "")
+		item["content_preview"] = contentPreview(rendered, 200, lang)
+
+		if sendDefaults[sig.ID] {
+			item["is_send_default"] = true
+		}
+		if replyDefaults[sig.ID] {
+			item["is_reply_default"] = true
+		}
+
+		items = append(items, item)
+	}
+
+	runtime.OutFormat(
+		map[string]interface{}{"signatures": items},
+		&output.Meta{Count: len(items)},
+		nil,
+	)
+	return nil
+}
+
+func executeSignatureDetail(runtime *common.RuntimeContext, resp *signature.GetSignaturesResponse, sigID, mailboxID string) error {
+	var sig *signature.Signature
+	for i := range resp.Signatures {
+		if resp.Signatures[i].ID == sigID {
+			sig = &resp.Signatures[i]
+			break
+		}
+	}
+	if sig == nil {
+		return output.ErrValidation("signature not found: %s", sigID)
+	}
+
+	lang := resolveLang(runtime)
+
+	detail := map[string]interface{}{
+		"id":   sig.ID,
+		"name": sig.Name,
+		"type": string(sig.SignatureType),
+	}
+
+	// Usage info.
+	for _, usage := range resp.Usages {
+		if usage.SendMailSignatureID == sig.ID {
+			detail["is_send_default"] = true
+		}
+		if usage.ReplySignatureID == sig.ID {
+			detail["is_reply_default"] = true
+		}
+	}
+
+	// Images metadata — output the full structure from API.
+	if len(sig.Images) > 0 {
+		detail["images"] = sig.Images
+	}
+
+	// Template variables (TENANT signatures): show resolved values.
+	if sig.HasTemplateVars() {
+		vars := make(map[string]string, len(sig.UserFields))
+		for key, field := range sig.UserFields {
+			vars[key] = field.Resolve(lang)
+		}
+		detail["template_vars"] = vars
+	}
+
+	// Rendered content preview.
+	rendered := signature.InterpolateTemplate(sig, lang, "", "")
+	detail["content_preview"] = contentPreview(rendered, 200, lang)
+
+	runtime.Out(detail, nil)
+	return nil
+}
+
+// resolveLang maps CLI config lang ("zh"/"en") to i18n key ("zh_cn"/"en_us").
+func resolveLang(runtime *common.RuntimeContext) string {
+	multi, err := core.LoadMultiAppConfig()
+	if err != nil {
+		return "zh_cn"
+	}
+	cfg, err := runtime.Factory.Config()
+	if err != nil {
+		return "zh_cn"
+	}
+	app := multi.FindApp(cfg.ProfileName)
+	if app == nil {
+		return "zh_cn"
+	}
+	switch app.Lang {
+	case "en":
+		return "en_us"
+	case "ja":
+		return "ja_jp"
+	default:
+		return "zh_cn"
+	}
+}
+
+// contentPreview converts HTML to a compact plain-text preview.
+// <img> tags become a localized image placeholder, all other tags become
+// spaces, then consecutive whitespace is collapsed. Result is truncated
+// to maxLen runes.
+func contentPreview(html string, maxLen int, lang string) string {
+	placeholder := "[image]"
+	if strings.HasPrefix(lang, "zh") {
+		placeholder = "[图片]"
+	}
+	imgRe := regexp.MustCompile(`<img[^>]*>`)
+	s := imgRe.ReplaceAllString(html, placeholder)
+
+	// Strip remaining tags, replacing each with a space.
+	var result strings.Builder
+	inTag := false
+	for _, r := range s {
+		switch {
+		case r == '<':
+			inTag = true
+			result.WriteByte(' ')
+		case r == '>':
+			inTag = false
+		case !inTag:
+			result.WriteRune(r)
+		}
+	}
+
+	// Collapse whitespace and trim.
+	text := strings.Join(strings.Fields(result.String()), " ")
+	text = strings.TrimSpace(text)
+
+	runes := []rune(text)
+	if len(runes) <= maxLen {
+		return text
+	}
+	return string(runes[:maxLen]) + "..."
+}
diff --git a/shortcuts/mail/shortcuts.go b/shortcuts/mail/shortcuts.go
index eb9f2d27..ef05b37a 100644
--- a/shortcuts/mail/shortcuts.go
+++ b/shortcuts/mail/shortcuts.go
@@ -19,5 +19,6 @@ func Shortcuts() []common.Shortcut {
 		MailDraftCreate,
 		MailDraftEdit,
 		MailForward,
+		MailSignature,
 	}
 }
diff --git a/shortcuts/mail/signature/interpolate.go b/shortcuts/mail/signature/interpolate.go
new file mode 100644
index 00000000..c3525bce
--- /dev/null
+++ b/shortcuts/mail/signature/interpolate.go
@@ -0,0 +1,157 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package signature
+
+import (
+	"encoding/json"
+	"regexp"
+	"strings"
+)
+
+// variableMetaProps represents the JSON structure in data-variable-meta-props attributes.
+type variableMetaProps struct {
+	ID          string `json:"id"`
+	Type        string `json:"type"`        // "text" or "image"
+	DisplayName string `json:"displayName"` // human-readable label
+	Width       string `json:"width"`       // image width (for type=image)
+	Style       string `json:"style"`       // CSS style
+	Circle      bool   `json:"circle"`      // circular image
+}
+
+// variableSpanRe matches <span data-variable-meta-props='...'> and captures the JSON and inner content.
+// Group 1: JSON attribute value (double-quoted), Group 2: (single-quoted), Group 3: inner content.
+//
+// Limitation: uses regex instead of DOM parsing (Go has no built-in DOMParser like JS).
+// If a variable <span> contains nested <span> tags, [\s\S]*? will match to the
+// innermost </span>, potentially truncating content. In practice, Lark's signature
+// templates do not nest <span> inside variable spans (verified against mail-editor
+// source and test data). If this becomes an issue, consider using golang.org/x/net/html.
+var variableSpanRe = regexp.MustCompile(
+	`<span\s+data-variable-meta-props=(?:"([^"]*?)"|'([^']*?)')>([\s\S]*?)</span>`)
+
+// InterpolateTemplate replaces template variables in a TENANT signature's content HTML.
+// For USER signatures (no template variables), it returns sig.Content unchanged.
+//
+// Parameters:
+//   - sig: the signature object
+//   - lang: language code for i18n ("zh_cn", "en_us", "ja_jp")
+//   - senderName: sender display name (overrides B-NAME)
+//   - senderEmail: sender email address (overrides B-ENTERPRISE-EMAIL)
+func InterpolateTemplate(sig *Signature, lang, senderName, senderEmail string) string {
+	if !sig.HasTemplateVars() {
+		return sig.Content
+	}
+
+	// Build value map from user_fields with i18n resolution.
+	valueMap := make(map[string]string, len(sig.UserFields)+2)
+	for key, field := range sig.UserFields {
+		valueMap[key] = field.Resolve(lang)
+	}
+
+	// Fixed injections override API values.
+	if senderName != "" {
+		valueMap["B-NAME"] = senderName
+	}
+	if senderEmail != "" {
+		valueMap["B-ENTERPRISE-EMAIL"] = senderEmail
+	}
+
+	// Replace each <span data-variable-meta-props='...'> with interpolated content.
+	result := variableSpanRe.ReplaceAllStringFunc(sig.Content, func(match string) string {
+		submatches := variableSpanRe.FindStringSubmatch(match)
+		if submatches == nil {
+			return match
+		}
+
+		// JSON is in group 1 (double-quoted) or group 2 (single-quoted).
+		attrJSON := submatches[1]
+		if attrJSON == "" {
+			attrJSON = submatches[2]
+		}
+
+		// Unescape HTML entities in the JSON attribute value.
+		attrJSON = unescapeHTMLEntities(attrJSON)
+
+		var meta variableMetaProps
+		if err := json.Unmarshal([]byte(attrJSON), &meta); err != nil {
+			return match // preserve original on parse failure
+		}
+
+		val, ok := valueMap[meta.ID]
+		if !ok {
+			val = "" // variable not in map, replace with empty
+		}
+
+		switch meta.Type {
+		case "text":
+			return interpolateText(val, meta.Style)
+		case "image":
+			return interpolateImage(val, meta)
+		default:
+			return val
+		}
+	})
+
+	return result
+}
+
+// interpolateText returns the replacement for a text variable.
+func interpolateText(val, style string) string {
+	if val == "" {
+		return ""
+	}
+	// If value looks like a URL, wrap in <a>.
+	if isURL(val) {
+		escaped := escapeHTML(val)
+		return `<a href="` + escaped + `" target="_blank" rel="noopener noreferrer">` + escaped + `</a>`
+	}
+	if style != "" {
+		return `<span style="` + escapeHTML(style) + `">` + escapeHTML(val) + `</span>`
+	}
+	return escapeHTML(val)
+}
+
+// interpolateImage returns the replacement for an image variable.
+func interpolateImage(val string, meta variableMetaProps) string {
+	if val == "" {
+		return ""
+	}
+	var attrs []string
+	attrs = append(attrs, `src="`+escapeHTML(val)+`"`)
+	if meta.Width != "" {
+		attrs = append(attrs, `width="`+escapeHTML(meta.Width)+`"`)
+	}
+	var styles []string
+	if meta.Style != "" {
+		styles = append(styles, meta.Style)
+	}
+	if meta.Circle {
+		styles = append(styles, "border-radius: 100%")
+	}
+	if len(styles) > 0 {
+		attrs = append(attrs, `style="`+escapeHTML(strings.Join(styles, ";"))+`"`)
+	}
+	return `<img ` + strings.Join(attrs, " ") + `>`
+}
+
+func isURL(s string) bool {
+	s = strings.TrimSpace(s)
+	return strings.HasPrefix(s, "http://") || strings.HasPrefix(s, "https://")
+}
+
+func escapeHTML(s string) string {
+	s = strings.ReplaceAll(s, "&", "&amp;")
+	s = strings.ReplaceAll(s, "<", "&lt;")
+	s = strings.ReplaceAll(s, ">", "&gt;")
+	s = strings.ReplaceAll(s, `"`, "&quot;")
+	return s
+}
+
+func unescapeHTMLEntities(s string) string {
+	s = strings.ReplaceAll(s, "&quot;", `"`)
+	s = strings.ReplaceAll(s, "&amp;", "&")
+	s = strings.ReplaceAll(s, "&lt;", "<")
+	s = strings.ReplaceAll(s, "&gt;", ">")
+	return s
+}
diff --git a/shortcuts/mail/signature/interpolate_test.go b/shortcuts/mail/signature/interpolate_test.go
new file mode 100644
index 00000000..d58a484a
--- /dev/null
+++ b/shortcuts/mail/signature/interpolate_test.go
@@ -0,0 +1,137 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package signature
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestInterpolateTemplate_UserSignatureUnchanged(t *testing.T) {
+	sig := &Signature{
+		Content:       "<b>My signature</b>",
+		SignatureType: SignatureTypeUser,
+	}
+	got := InterpolateTemplate(sig, "zh_cn", "Alice", "alice@example.com")
+	if got != sig.Content {
+		t.Errorf("USER signature should be unchanged, got %q", got)
+	}
+}
+
+func TestInterpolateTemplate_TenantTextVariables(t *testing.T) {
+	sig := &Signature{
+		Content:          `姓名：<span data-variable-meta-props='{"id":"B-NAME","type":"text"}'>{text}</span>, 部门：<span data-variable-meta-props='{"id":"B-DEPARTMENT","type":"text"}'>{text}</span>`,
+		SignatureType:    SignatureTypeTenant,
+		TemplateJSONKeys: []string{"B-NAME", "B-DEPARTMENT"},
+		UserFields: map[string]UserFieldValue{
+			"B-NAME":       {DefaultVal: "张三", I18nVals: map[string]string{"zh_cn": "", "en_us": "Zhang San"}},
+			"B-DEPARTMENT": {DefaultVal: "默认部门", I18nVals: map[string]string{"zh_cn": "研发部", "en_us": "R&D"}},
+		},
+	}
+
+	// zh_cn: B-DEPARTMENT should resolve to "研发部" (from i18n), B-NAME overridden by senderName
+	got := InterpolateTemplate(sig, "zh_cn", "李四", "lisi@example.com")
+	if !strings.Contains(got, "李四") {
+		t.Errorf("expected senderName override for B-NAME, got %q", got)
+	}
+	if !strings.Contains(got, "研发部") {
+		t.Errorf("expected zh_cn i18n value for B-DEPARTMENT, got %q", got)
+	}
+	if strings.Contains(got, "{text}") {
+		t.Errorf("should not contain raw placeholder {text}, got %q", got)
+	}
+	if strings.Contains(got, "data-variable-meta-props") {
+		t.Errorf("should not contain data-variable-meta-props attribute, got %q", got)
+	}
+}
+
+func TestInterpolateTemplate_I18nFallback(t *testing.T) {
+	sig := &Signature{
+		Content:          `<span data-variable-meta-props='{"id":"B-DEPARTMENT","type":"text"}'>{text}</span>`,
+		SignatureType:    SignatureTypeTenant,
+		TemplateJSONKeys: []string{"B-DEPARTMENT"},
+		UserFields: map[string]UserFieldValue{
+			"B-DEPARTMENT": {DefaultVal: "默认部门", I18nVals: map[string]string{"zh_cn": "", "en_us": ""}},
+		},
+	}
+
+	got := InterpolateTemplate(sig, "zh_cn", "", "")
+	if !strings.Contains(got, "默认部门") {
+		t.Errorf("expected fallback to DefaultVal, got %q", got)
+	}
+}
+
+func TestInterpolateTemplate_HTMLEntityEscaping(t *testing.T) {
+	// Simulate the HTML-entity-escaped attribute format from real API responses.
+	sig := &Signature{
+		Content:          `<span data-variable-meta-props="{&quot;id&quot;:&quot;B-NAME&quot;,&quot;type&quot;:&quot;text&quot;}">{text}</span>`,
+		SignatureType:    SignatureTypeTenant,
+		TemplateJSONKeys: []string{"B-NAME"},
+		UserFields: map[string]UserFieldValue{
+			"B-NAME": {DefaultVal: "default"},
+		},
+	}
+
+	got := InterpolateTemplate(sig, "zh_cn", "陈煌", "")
+	if !strings.Contains(got, "陈煌") {
+		t.Errorf("expected interpolated name, got %q", got)
+	}
+}
+
+func TestInterpolateTemplate_URLAsText(t *testing.T) {
+	sig := &Signature{
+		Content:          `<span data-variable-meta-props='{"id":"B-URL","type":"text"}'>{text}</span>`,
+		SignatureType:    SignatureTypeTenant,
+		TemplateJSONKeys: []string{"B-URL"},
+		UserFields: map[string]UserFieldValue{
+			"B-URL": {DefaultVal: "https://example.com"},
+		},
+	}
+
+	got := InterpolateTemplate(sig, "zh_cn", "", "")
+	if !strings.Contains(got, "<a href=") {
+		t.Errorf("expected URL to be wrapped in <a> tag, got %q", got)
+	}
+	if !strings.Contains(got, "https://example.com") {
+		t.Errorf("expected URL in output, got %q", got)
+	}
+}
+
+func TestInterpolateTemplate_ImageVariable(t *testing.T) {
+	sig := &Signature{
+		Content:          `<span data-variable-meta-props='{"id":"B-LOGO","type":"image","width":"40"}'><img src="cid:old"/></span>`,
+		SignatureType:    SignatureTypeTenant,
+		TemplateJSONKeys: []string{"B-LOGO"},
+		UserFields: map[string]UserFieldValue{
+			"B-LOGO": {DefaultVal: "cid:new-logo-cid"},
+		},
+	}
+
+	got := InterpolateTemplate(sig, "zh_cn", "", "")
+	if !strings.Contains(got, `src="cid:new-logo-cid"`) {
+		t.Errorf("expected new image src, got %q", got)
+	}
+	if !strings.Contains(got, `width="40"`) {
+		t.Errorf("expected width attribute, got %q", got)
+	}
+}
+
+func TestUserFieldValue_Resolve(t *testing.T) {
+	v := UserFieldValue{
+		DefaultVal: "default",
+		I18nVals:   map[string]string{"zh_cn": "中文", "en_us": "", "ja_jp": "日本語"},
+	}
+	if got := v.Resolve("zh_cn"); got != "中文" {
+		t.Errorf("zh_cn = %q, want 中文", got)
+	}
+	if got := v.Resolve("en_us"); got != "default" {
+		t.Errorf("en_us (empty) should fallback to default, got %q", got)
+	}
+	if got := v.Resolve("ja_jp"); got != "日本語" {
+		t.Errorf("ja_jp = %q, want 日本語", got)
+	}
+	if got := v.Resolve("fr_fr"); got != "default" {
+		t.Errorf("unknown lang should fallback, got %q", got)
+	}
+}
diff --git a/shortcuts/mail/signature/model.go b/shortcuts/mail/signature/model.go
new file mode 100644
index 00000000..de2cac50
--- /dev/null
+++ b/shortcuts/mail/signature/model.go
@@ -0,0 +1,82 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package signature
+
+// SignatureType represents the type of a mail signature.
+type SignatureType string
+
+const (
+	SignatureTypeUser   SignatureType = "USER"
+	SignatureTypeTenant SignatureType = "TENANT"
+)
+
+// SignatureDevice represents the device platform a signature is designed for.
+type SignatureDevice string
+
+const (
+	DevicePC     SignatureDevice = "PC"
+	DeviceMobile SignatureDevice = "MOBILE"
+)
+
+// SignatureImage holds metadata for an inline image embedded in a signature.
+type SignatureImage struct {
+	ImageName   string `json:"image_name,omitempty"`
+	FileKey     string `json:"file_key,omitempty"`
+	CID         string `json:"cid,omitempty"`
+	FileSize    string `json:"file_size,omitempty"`
+	Header      string `json:"header,omitempty"`
+	ImageWidth  int32  `json:"image_width,omitempty"`
+	ImageHeight int32  `json:"image_height,omitempty"`
+	DownloadURL string `json:"download_url,omitempty"`
+}
+
+// UserFieldValue holds a template variable value with multi-language support.
+type UserFieldValue struct {
+	DefaultVal string            `json:"default_val"`
+	I18nVals   map[string]string `json:"i18n_vals"` // keys: "zh_cn", "en_us", "ja_jp"
+}
+
+// Resolve returns the localized value for the given language code.
+// Falls back to DefaultVal when the language key is missing or empty.
+func (v UserFieldValue) Resolve(lang string) string {
+	if val, ok := v.I18nVals[lang]; ok && val != "" {
+		return val
+	}
+	return v.DefaultVal
+}
+
+// Signature represents a single mail signature returned by the API.
+type Signature struct {
+	ID               string                    `json:"id"`
+	Name             string                    `json:"name"`
+	SignatureType    SignatureType             `json:"signature_type"`
+	SignatureDevice  SignatureDevice           `json:"signature_device"`
+	Content          string                    `json:"content"`
+	Images           []SignatureImage          `json:"images,omitempty"`
+	TemplateJSONKeys []string                  `json:"template_json_keys,omitempty"`
+	UserFields       map[string]UserFieldValue `json:"user_fields,omitempty"`
+}
+
+// IsTenant returns true if this is a tenant/corporate signature with template variables.
+func (s *Signature) IsTenant() bool {
+	return s.SignatureType == SignatureTypeTenant
+}
+
+// HasTemplateVars returns true if the signature contains template variables that need interpolation.
+func (s *Signature) HasTemplateVars() bool {
+	return len(s.TemplateJSONKeys) > 0
+}
+
+// SignatureUsage indicates which signature is used by default for a given email address.
+type SignatureUsage struct {
+	EmailAddress        string `json:"email_address"`
+	SendMailSignatureID string `json:"send_mail_signature_id"`
+	ReplySignatureID    string `json:"reply_signature_id"`
+}
+
+// GetSignaturesResponse is the parsed response from the get_signatures API.
+type GetSignaturesResponse struct {
+	Signatures []Signature      `json:"signatures"`
+	Usages     []SignatureUsage `json:"usages"`
+}
diff --git a/shortcuts/mail/signature/provider.go b/shortcuts/mail/signature/provider.go
new file mode 100644
index 00000000..1dda6696
--- /dev/null
+++ b/shortcuts/mail/signature/provider.go
@@ -0,0 +1,70 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package signature
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/url"
+
+	"github.com/larksuite/cli/shortcuts/common"
+)
+
+// processCache holds per-mailbox cached responses.
+// CLI runs one command per process, so a package-level map is sufficient —
+// it is naturally scoped to a single Execute lifecycle.
+var processCache = map[string]*GetSignaturesResponse{}
+
+func signaturesPath(mailboxID string) string {
+	return "/open-apis/mail/v1/user_mailboxes/" + url.PathEscape(mailboxID) + "/settings/signatures"
+}
+
+// ListAll fetches all signatures and usage info for a mailbox.
+// Results are cached per mailboxID within the current Execute lifecycle.
+func ListAll(runtime *common.RuntimeContext, mailboxID string) (*GetSignaturesResponse, error) {
+	if cached, ok := processCache[mailboxID]; ok {
+		return cached, nil
+	}
+
+	data, err := runtime.CallAPI("GET", signaturesPath(mailboxID), nil, nil)
+	if err != nil {
+		return nil, fmt.Errorf("get signatures: %w", err)
+	}
+
+	raw, err := json.Marshal(data)
+	if err != nil {
+		return nil, fmt.Errorf("get signatures: marshal response: %w", err)
+	}
+
+	var resp GetSignaturesResponse
+	if err := json.Unmarshal(raw, &resp); err != nil {
+		return nil, fmt.Errorf("get signatures: unmarshal response: %w", err)
+	}
+
+	processCache[mailboxID] = &resp
+	return &resp, nil
+}
+
+// List returns all signatures for a mailbox.
+func List(runtime *common.RuntimeContext, mailboxID string) ([]Signature, error) {
+	resp, err := ListAll(runtime, mailboxID)
+	if err != nil {
+		return nil, err
+	}
+	return resp.Signatures, nil
+}
+
+// Get returns a single signature by ID. Returns an error if not found.
+func Get(runtime *common.RuntimeContext, mailboxID, signatureID string) (*Signature, error) {
+	resp, err := ListAll(runtime, mailboxID)
+	if err != nil {
+		return nil, err
+	}
+	for i := range resp.Signatures {
+		if resp.Signatures[i].ID == signatureID {
+			return &resp.Signatures[i], nil
+		}
+	}
+	return nil, fmt.Errorf("signature not found: %s", signatureID)
+}
diff --git a/shortcuts/mail/signature_compose.go b/shortcuts/mail/signature_compose.go
new file mode 100644
index 00000000..71e7a6a7
--- /dev/null
+++ b/shortcuts/mail/signature_compose.go
@@ -0,0 +1,245 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package mail
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/larksuite/cli/shortcuts/common"
+	draftpkg "github.com/larksuite/cli/shortcuts/mail/draft"
+	"github.com/larksuite/cli/shortcuts/mail/emlbuilder"
+	"github.com/larksuite/cli/shortcuts/mail/signature"
+)
+
+// signatureFlag is the common flag definition for --signature-id, shared by all compose shortcuts.
+var signatureFlag = common.Flag{
+	Name: "signature-id",
+	Desc: "Optional. Signature ID to append after body content. Run `mail +signature` to list available signatures.",
+}
+
+// signatureResult holds the pre-processed signature data ready for HTML injection.
+type signatureResult struct {
+	ID              string
+	RenderedContent string
+	Images          []draftpkg.SignatureImage
+}
+
+// resolveSignature fetches, interpolates, and downloads images for a signature.
+// Returns nil if signatureID is empty.
+// resolveSignature fetches, interpolates, and downloads images for a signature.
+// fromEmail is the --from address (may be an alias); used to match the correct
+// sender identity for template interpolation. Pass "" to use the primary address.
+func resolveSignature(ctx context.Context, runtime *common.RuntimeContext, mailboxID, signatureID, fromEmail string) (*signatureResult, error) {
+	if signatureID == "" {
+		return nil, nil
+	}
+
+	sig, err := signature.Get(runtime, mailboxID, signatureID)
+	if err != nil {
+		return nil, err
+	}
+
+	// Resolve sender info for template interpolation.
+	lang := resolveLang(runtime)
+	senderName, senderEmail := resolveSenderInfo(runtime, mailboxID, fromEmail)
+	rendered := signature.InterpolateTemplate(sig, lang, senderName, senderEmail)
+
+	// Download signature inline images. The file_key field contains a
+	// direct download URL provided by the mail backend.
+	var images []draftpkg.SignatureImage
+	for _, img := range sig.Images {
+		if img.DownloadURL == "" || img.CID == "" {
+			continue
+		}
+		data, ct, err := downloadSignatureImage(runtime, img.DownloadURL, img.ImageName)
+		if err != nil {
+			return nil, fmt.Errorf("failed to download signature image %s: %w", img.ImageName, err)
+		}
+		images = append(images, draftpkg.SignatureImage{
+			CID:         img.CID,
+			ContentType: ct,
+			FileName:    img.ImageName,
+			Data:        data,
+		})
+	}
+
+	return &signatureResult{
+		ID:              sig.ID,
+		RenderedContent: rendered,
+		Images:          images,
+	}, nil
+}
+
+// injectSignatureIntoBody inserts signature HTML into the body, before the quote block.
+// It removes any existing signature first, then places the new signature between
+// the user-authored content and the quote block (if any).
+// Returns the new full HTML body.
+func injectSignatureIntoBody(bodyHTML string, sig *signatureResult) string {
+	if sig == nil {
+		return bodyHTML
+	}
+	cleaned := draftpkg.RemoveSignatureHTML(bodyHTML)
+	userContent, quote := draftpkg.SplitAtQuote(cleaned)
+	sigBlock := draftpkg.SignatureSpacing() + draftpkg.BuildSignatureHTML(sig.ID, sig.RenderedContent)
+	return userContent + sigBlock + quote
+}
+
+// addSignatureImagesToBuilder adds signature inline images to the EML builder.
+func addSignatureImagesToBuilder(bld emlbuilder.Builder, sig *signatureResult) emlbuilder.Builder {
+	if sig == nil {
+		return bld
+	}
+	for _, img := range sig.Images {
+		cid := normalizeInlineCID(img.CID)
+		if cid == "" {
+			continue
+		}
+		bld = bld.AddInline(img.Data, img.ContentType, img.FileName, cid)
+	}
+	return bld
+}
+
+// resolveSenderInfo fetches senderName and senderEmail via the send_as API.
+// resolveSenderInfo fetches send_as addresses and returns the name/email
+// for signature interpolation. If fromEmail is non-empty, it matches
+// that address in the sendable list (for alias/send_as scenarios);
+// otherwise falls back to the first (primary) address.
+func resolveSenderInfo(runtime *common.RuntimeContext, mailboxID, fromEmail string) (name, email string) {
+	data, err := runtime.CallAPI("GET", mailboxPath(mailboxID, "settings", "send_as"), nil, nil)
+	if err != nil {
+		return "", ""
+	}
+	addrs, ok := data["sendable_addresses"].([]interface{})
+	if !ok || len(addrs) == 0 {
+		return "", ""
+	}
+	// If fromEmail is specified, find the matching address.
+	if fromEmail != "" {
+		for _, a := range addrs {
+			m, ok := a.(map[string]interface{})
+			if !ok {
+				continue
+			}
+			e, _ := m["email_address"].(string)
+			if strings.EqualFold(e, fromEmail) {
+				n, _ := m["name"].(string)
+				return n, e
+			}
+		}
+	}
+	// Fall back to the first sendable address (primary).
+	first, ok := addrs[0].(map[string]interface{})
+	if !ok {
+		return "", ""
+	}
+	n, _ := first["name"].(string)
+	e, _ := first["email_address"].(string)
+	return n, e
+}
+
+// downloadSignatureImage downloads a signature image by its direct URL.
+// Security: enforces https, does not send Bearer token (URL is pre-signed),
+// uses context timeout, and limits response size. Aligned with
+// downloadAttachmentContent in helpers.go.
+func downloadSignatureImage(runtime *common.RuntimeContext, downloadURL, filename string) ([]byte, string, error) {
+	u, err := url.Parse(downloadURL)
+	if err != nil {
+		return nil, "", fmt.Errorf("signature image download: invalid URL: %w", err)
+	}
+	if u.Scheme != "https" {
+		return nil, "", fmt.Errorf("signature image download: URL must use https (got %q)", u.Scheme)
+	}
+	if u.Host == "" {
+		return nil, "", fmt.Errorf("signature image download: URL has no host")
+	}
+
+	httpClient, err := runtime.Factory.HttpClient()
+	if err != nil {
+		return nil, "", fmt.Errorf("signature image download: %w", err)
+	}
+	ctx, cancel := context.WithTimeout(runtime.Ctx(), 30*time.Second)
+	defer cancel()
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, downloadURL, nil)
+	if err != nil {
+		return nil, "", fmt.Errorf("signature image download: %w", err)
+	}
+	// Do NOT send Authorization: the download URL is pre-signed.
+
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return nil, "", fmt.Errorf("signature image download: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 400 {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))
+		return nil, "", fmt.Errorf("signature image download: HTTP %d: %s", resp.StatusCode, string(body))
+	}
+
+	const maxSize = 10 * 1024 * 1024
+	data, err := io.ReadAll(io.LimitReader(resp.Body, maxSize+1))
+	if err != nil {
+		return nil, "", fmt.Errorf("signature image download: read body: %w", err)
+	}
+	if len(data) > maxSize {
+		return nil, "", fmt.Errorf("signature image download: file exceeds 10MB limit")
+	}
+
+	ct := resp.Header.Get("Content-Type")
+	if ct == "" || ct == "application/octet-stream" {
+		ct = contentTypeFromFilename(filename)
+	}
+
+	return data, ct, nil
+}
+
+func contentTypeFromFilename(name string) string {
+	ext := strings.ToLower(filepath.Ext(name))
+	switch ext {
+	case ".png":
+		return "image/png"
+	case ".jpg", ".jpeg":
+		return "image/jpeg"
+	case ".gif":
+		return "image/gif"
+	case ".webp":
+		return "image/webp"
+	case ".svg":
+		return "image/svg+xml"
+	case ".bmp":
+		return "image/bmp"
+	default:
+		return "application/octet-stream"
+	}
+}
+
+// signatureCIDs returns the CID list from a signatureResult, for inline CID validation.
+func signatureCIDs(sig *signatureResult) []string {
+	if sig == nil {
+		return nil
+	}
+	cids := make([]string, 0, len(sig.Images))
+	for _, img := range sig.Images {
+		cid := normalizeInlineCID(img.CID)
+		if cid != "" {
+			cids = append(cids, cid)
+		}
+	}
+	return cids
+}
+
+// validateSignatureWithPlainText returns an error if both --plain-text and --signature-id are set.
+func validateSignatureWithPlainText(plainText bool, signatureID string) error {
+	if plainText && signatureID != "" {
+		return fmt.Errorf("--plain-text and --signature-id are mutually exclusive: signatures require HTML mode")
+	}
+	return nil
+}
diff --git a/skills/lark-mail/SKILL.md b/skills/lark-mail/SKILL.md
index 7f33064e..0716d713 100644
--- a/skills/lark-mail/SKILL.md
+++ b/skills/lark-mail/SKILL.md
@@ -326,6 +326,7 @@ Shortcut 是对常用操作的高级封装（`lark-cli mail +<verb> [flags]`）
 | [`+draft-create`](references/lark-mail-draft-create.md) | Create a brand-new mail draft from scratch (NOT for reply or forward). For reply drafts use +reply; for forward drafts use +forward. Only use +draft-create when composing a new email with no parent message. |
 | [`+draft-edit`](references/lark-mail-draft-edit.md) | Use when updating an existing mail draft without sending it. Prefer this shortcut over calling raw drafts.get or drafts.update directly, because it performs draft-safe MIME read/patch/write editing while preserving unchanged structure, attachments, and headers where possible. |
 | [`+forward`](references/lark-mail-forward.md) | Forward a message and save as draft (default). Use --confirm-send to send immediately after user confirmation. Original message block included automatically. |
+| [`+signature`](references/lark-mail-signature.md) | List or view email signatures with default usage info. |
 
 ## API Resources
 
@@ -406,6 +407,7 @@ lark-cli mail <resource> <method> [flags] # 调用 API
 
 ### user_mailbox.settings
 
+  - `get_signatures` — 获取用户邮箱签名列表
   - `send_as` — 获取账号的所有可发信地址，包括主地址、别名地址、邮件组。可以使用用户地址访问该接口，也可以使用用户有权限的公共邮箱地址访问该接口。
 
 ### user_mailbox.threads
@@ -467,6 +469,7 @@ lark-cli mail <resource> <method> [flags] # 调用 API
 | `user_mailbox.rules.list` | `mail:user_mailbox.rule:read` |
 | `user_mailbox.rules.reorder` | `mail:user_mailbox.rule:write` |
 | `user_mailbox.rules.update` | `mail:user_mailbox.rule:write` |
+| `user_mailbox.settings.get_signatures` | `mail:user_mailbox:readonly` |
 | `user_mailbox.settings.send_as` | `mail:user_mailbox:readonly` |
 | `user_mailbox.threads.batch_modify` | `mail:user_mailbox.message:modify` |
 | `user_mailbox.threads.batch_trash` | `mail:user_mailbox.message:modify` |
diff --git a/skills/lark-mail/references/lark-mail-draft-create.md b/skills/lark-mail/references/lark-mail-draft-create.md
index 80ca0bfe..22f260c1 100644
--- a/skills/lark-mail/references/lark-mail-draft-create.md
+++ b/skills/lark-mail/references/lark-mail-draft-create.md
@@ -51,6 +51,7 @@ lark-cli mail +draft-create --to alice@example.com --subject '测试' --body 'te
 | `--plain-text` | 否 | 强制纯文本模式，忽略 HTML 自动检测。不可与 `--inline` 同时使用 |
 | `--attach <paths>` | 否 | 普通附件文件路径，多个用逗号分隔。相对路径 |
 | `--inline <json>` | 否 | 高级用法：手动指定内嵌图片 CID 映射。推荐直接在 `--body` 中使用 `<img src="./path" />`（自动解析）。仅在需要精确控制 CID 命名时使用此参数。格式：`'[{"cid":"mycid","file_path":"./logo.png"}]'`，在 body 中用 `<img src="cid:mycid">` 引用。不可与 `--plain-text` 同时使用 |
+| `--signature-id <id>` | 否 | 签名 ID。附加邮箱签名到正文末尾。运行 `mail +signature` 查看可用签名。不可与 `--plain-text` 同时使用 |
 | `--format <mode>` | 否 | 输出格式：`json`（默认）/ `pretty` / `table` / `ndjson` / `csv` |
 | `--dry-run` | 否 | 仅打印请求，不执行 |
 
diff --git a/skills/lark-mail/references/lark-mail-draft-edit.md b/skills/lark-mail/references/lark-mail-draft-edit.md
index 0875a18a..c88d6a0b 100644
--- a/skills/lark-mail/references/lark-mail-draft-edit.md
+++ b/skills/lark-mail/references/lark-mail-draft-edit.md
@@ -219,6 +219,22 @@ lark-cli mail +draft-edit --draft-id <draft_id> --inspect
 { "op": "remove_inline", "target": { "cid": "logo" } }
 ```
 
+`insert_signature`
+
+```json
+{ "op": "insert_signature", "signature_id": "<签名ID>" }
+```
+
+插入签名到正文末尾（引用块之前）。如已有签名则先移除再插入。运行 `mail +signature` 获取可用签名 ID。签名中的模板变量会自动替换，内联图片自动下载嵌入。
+
+`remove_signature`
+
+```json
+{ "op": "remove_signature" }
+```
+
+移除草稿中的现有签名（含签名前的空行间距）。如签名包含内联图片且正文不再引用这些图片，对应的 MIME part 也会一并移除。
+
 注意事项：
 
 - `ops` 按顺序执行
@@ -228,6 +244,7 @@ lark-cli mail +draft-edit --draft-id <draft_id> --inspect
 - **`set_body` 是完整替换** — 它替换整个正文内容（包括引用区）
 - **`set_reply_body` 仅替换引用区前面的用户撰写部分** — 引用区自动重新拼接；value 只传用户撰写内容，不要包含引用区；如果用户要修改引用区内容，用 `set_body` 全量覆盖
 - 通过 `--inspect` 返回的 `has_quoted_content` 字段可判断草稿是否包含引用区
+- 通过 `--inspect` 返回的 `has_signature` / `signature_id` 字段可判断草稿是否包含签名
 
 ## 返回值
 
diff --git a/skills/lark-mail/references/lark-mail-forward.md b/skills/lark-mail/references/lark-mail-forward.md
index 17a271d4..d2653587 100644
--- a/skills/lark-mail/references/lark-mail-forward.md
+++ b/skills/lark-mail/references/lark-mail-forward.md
@@ -66,6 +66,7 @@ lark-cli mail +forward --message-id <邮件ID> --to alice@example.com --dry-run
 | `--plain-text` | 否 | 强制纯文本模式，忽略所有 HTML 自动检测。不可与 `--inline` 同时使用 |
 | `--attach <paths>` | 否 | 附件文件路径，多个用逗号分隔，追加在原邮件附件之后。相对路径 |
 | `--inline <json>` | 否 | 高级用法：手动指定内嵌图片 CID 映射。推荐直接在 `--body` 中使用 `<img src="./path" />`（自动解析）。仅在需要精确控制 CID 命名时使用此参数。格式：`'[{"cid":"mycid","file_path":"./logo.png"}]'`，在 body 中用 `<img src="cid:mycid">` 引用。不可与 `--plain-text` 同时使用 |
+| `--signature-id <id>` | 否 | 签名 ID。附加邮箱签名到转发正文与引用块之间。运行 `mail +signature` 查看可用签名。不可与 `--plain-text` 同时使用 |
 | `--confirm-send` | 否 | 确认发送转发（默认只保存草稿）。仅在用户明确确认后使用 |
 | `--send-time <timestamp>` | 否 | 定时发送时间，Unix 时间戳（秒）。需至少为当前时间 + 5 分钟。配合 `--confirm-send` 使用可定时发送邮件 |
 | `--dry-run` | 否 | 仅打印请求，不执行 |
diff --git a/skills/lark-mail/references/lark-mail-reply-all.md b/skills/lark-mail/references/lark-mail-reply-all.md
index 645f758a..ec3d470f 100644
--- a/skills/lark-mail/references/lark-mail-reply-all.md
+++ b/skills/lark-mail/references/lark-mail-reply-all.md
@@ -70,6 +70,7 @@ lark-cli mail +reply-all --message-id <邮件ID> --body '测试' --dry-run
 | `--plain-text` | 否 | 强制纯文本模式，忽略所有 HTML 自动检测。不可与 `--inline` 同时使用 |
 | `--attach <paths>` | 否 | 附件文件路径，多个用逗号分隔。相对路径 |
 | `--inline <json>` | 否 | 高级用法：手动指定内嵌图片 CID 映射。推荐直接在 `--body` 中使用 `<img src="./path" />`（自动解析）。仅在需要精确控制 CID 命名时使用此参数。格式：`'[{"cid":"mycid","file_path":"./logo.png"}]'`，在 body 中用 `<img src="cid:mycid">` 引用。不可与 `--plain-text` 同时使用 |
+| `--signature-id <id>` | 否 | 签名 ID。附加邮箱签名到回复正文与引用块之间。运行 `mail +signature` 查看可用签名。不可与 `--plain-text` 同时使用 |
 | `--confirm-send` | 否 | 确认发送回复（默认只保存草稿）。仅在用户明确确认后使用 |
 | `--send-time <timestamp>` | 否 | 定时发送时间，Unix 时间戳（秒）。需至少为当前时间 + 5 分钟。配合 `--confirm-send` 使用可定时发送邮件 |
 | `--dry-run` | 否 | 仅打印请求，不执行 |
diff --git a/skills/lark-mail/references/lark-mail-reply.md b/skills/lark-mail/references/lark-mail-reply.md
index c75902de..70b97558 100644
--- a/skills/lark-mail/references/lark-mail-reply.md
+++ b/skills/lark-mail/references/lark-mail-reply.md
@@ -73,6 +73,7 @@ lark-cli mail +reply --message-id <邮件ID> --body '<p>测试</p>' --dry-run
 | `--plain-text` | 否 | 强制纯文本模式，忽略所有 HTML 自动检测。不可与 `--inline` 同时使用 |
 | `--attach <paths>` | 否 | 附件文件路径，多个用逗号分隔。相对路径 |
 | `--inline <json>` | 否 | 高级用法：手动指定内嵌图片 CID 映射。推荐直接在 `--body` 中使用 `<img src="./path" />`（自动解析）。仅在需要精确控制 CID 命名时使用此参数。格式：`'[{"cid":"mycid","file_path":"./logo.png"}]'`，在 body 中用 `<img src="cid:mycid">` 引用。不可与 `--plain-text` 同时使用 |
+| `--signature-id <id>` | 否 | 签名 ID。附加邮箱签名到回复正文与引用块之间。运行 `mail +signature` 查看可用签名。不可与 `--plain-text` 同时使用 |
 | `--confirm-send` | 否 | 确认发送回复（默认只保存草稿）。仅在用户明确确认后使用 |
 | `--send-time <timestamp>` | 否 | 定时发送时间，Unix 时间戳（秒）。需至少为当前时间 + 5 分钟。配合 `--confirm-send` 使用可定时发送邮件 |
 | `--dry-run` | 否 | 仅打印请求，不执行 |
diff --git a/skills/lark-mail/references/lark-mail-send.md b/skills/lark-mail/references/lark-mail-send.md
index 1b4a4053..a08c0480 100644
--- a/skills/lark-mail/references/lark-mail-send.md
+++ b/skills/lark-mail/references/lark-mail-send.md
@@ -70,6 +70,7 @@ lark-cli mail +send --to alice@example.com --subject '测试' --body '<p>test</p
 | `--plain-text` | 否 | 强制纯文本模式，忽略 HTML 自动检测。不可与 `--inline` 同时使用 |
 | `--attach <paths>` | 否 | 附件文件路径，多个用逗号分隔。相对路径 |
 | `--inline <json>` | 否 | 高级用法：手动指定内嵌图片 CID 映射。推荐直接在 `--body` 中使用 `<img src="./path" />`（自动解析）。仅在需要精确控制 CID 命名时使用此参数。格式：`'[{"cid":"mycid","file_path":"./logo.png"}]'`，在 body 中用 `<img src="cid:mycid">` 引用。不可与 `--plain-text` 同时使用 |
+| `--signature-id <id>` | 否 | 签名 ID。附加邮箱签名到正文末尾。运行 `mail +signature` 查看可用签名。不可与 `--plain-text` 同时使用 |
 | `--confirm-send` | 否 | 确认发送邮件（默认只保存草稿）。仅在用户明确确认收件人和内容后使用 |
 | `--send-time <timestamp>` | 否 | 定时发送时间，Unix 时间戳（秒）。需至少为当前时间 + 5 分钟。配合 `--confirm-send` 使用可定时发送邮件 |
 | `--dry-run` | 否 | 仅打印请求，不执行 |
diff --git a/skills/lark-mail/references/lark-mail-signature.md b/skills/lark-mail/references/lark-mail-signature.md
new file mode 100644
index 00000000..03ad0c66
--- /dev/null
+++ b/skills/lark-mail/references/lark-mail-signature.md
@@ -0,0 +1,98 @@
+# mail +signature
+
+> **前置条件：** 先阅读 [`../../lark-shared/SKILL.md`](../../lark-shared/SKILL.md) 了解认证、全局参数和安全规则。
+
+查看邮箱签名列表或详情。返回签名的类型、默认使用情况、内容预览等信息。TENANT（企业）签名的模板变量会被自动替换为实际值。
+
+本 skill 对应 shortcut：`lark-cli mail +signature`。
+
+## 命令
+
+```bash
+# 列出所有签名
+lark-cli mail +signature
+
+# 查看某个签名的详情（渲染后的内容预览、模板变量值、图片信息）
+lark-cli mail +signature --detail <signature_id>
+
+# 指定邮箱
+lark-cli mail +signature --from shared@example.com
+```
+
+## 参数
+
+| 参数 | 必填 | 说明 |
+|------|------|------|
+| `--from <email>` | 否 | 邮箱地址（默认 `me`） |
+| `--detail <id>` | 否 | 签名 ID，查看详情。省略则列出所有签名 |
+
+## 返回值
+
+**列表模式：**
+
+```json
+{
+  "ok": true,
+  "data": {
+    "signatures": [
+      {
+        "id": "<签名ID>",
+        "name": "个人签名",
+        "type": "USER",
+        "content_preview": "这是我的签名内容 [image] 超链接哈哈"
+      },
+      {
+        "id": "<签名ID>",
+        "name": "企业签名",
+        "type": "TENANT",
+        "is_send_default": true,
+        "is_reply_default": true,
+        "content_preview": "企业签名 姓名：陈煌 部门：研发团队"
+      }
+    ]
+  }
+}
+```
+
+**详情模式（`--detail`）：**
+
+```json
+{
+  "ok": true,
+  "data": {
+    "id": "<签名ID>",
+    "name": "企业签名",
+    "type": "TENANT",
+    "is_send_default": true,
+    "is_reply_default": true,
+    "images": [
+      {"cid": "76CEB29E-...", "file_key": "121011...", "image_name": "image.png"}
+    ],
+    "template_vars": {"B-NAME": "陈煌", "B-DEPARTMENT": "研发团队"},
+    "content_preview": "企业签名 姓名：陈煌 部门：研发团队"
+  }
+}
+```
+
+## 字段说明
+
+| 字段 | 说明 |
+|------|------|
+| `type` | `USER`（用户签名，可编辑）或 `TENANT`（企业签名，管理员模板控制） |
+| `is_send_default` | 是否为新邮件的默认签名 |
+| `is_reply_default` | 是否为回复/转发的默认签名 |
+| `images` | 签名内联图片元数据（仅详情模式） |
+| `template_vars` | TENANT 签名的模板变量已替换值（仅详情模式） |
+| `content_preview` | 签名内容的纯文本预览（`<img>` 显示为 `[image]`，最长 200 字符） |
+
+## 与 compose shortcut 配合
+
+获取签名 ID 后，可在发送/回复/转发时附加签名：
+
+```bash
+# 查看签名列表获取 ID
+lark-cli mail +signature
+
+# 在发送邮件时附加签名
+lark-cli mail +send --to alice@example.com --subject '你好' --body '<p>内容</p>' --signature-id <签名ID>
+```