Merge branch 'main' into feat/markdown_renderer

go.mod

@@ -64,6 +64,7 @@ require (
 	github.com/uptrace/bun/dialect/pgdialect v1.2.9
 	github.com/uptrace/bun/dialect/sqlitedialect v1.2.9
 	github.com/uptrace/bun/extra/bunotel v1.2.9
+	github.com/yuin/goldmark v1.7.16
 	go.opentelemetry.io/collector/confmap v1.51.0
 	go.opentelemetry.io/collector/otelcol v0.144.0
 	go.opentelemetry.io/collector/pdata v1.51.0

go.sum

@@ -1144,6 +1144,8 @@ github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9de
 github.com/yuin/goldmark v1.1.32/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
+github.com/yuin/goldmark v1.7.16 h1:n+CJdUxaFMiDUNnWC3dMWCIQJSkxH4uz3ZwQBkAlVNE=
+github.com/yuin/goldmark v1.7.16/go.mod h1:ip/1k0VRfGynBgxOz0yCqHrbZXhcjxyuS66Brc7iBKg=
 github.com/yusufpapurcu/wmi v1.2.4 h1:zFUKzehAFReQwLys1b/iSMl+JQGSCSjtVqQn9bBrPo0=
 github.com/yusufpapurcu/wmi v1.2.4/go.mod h1:SBZ9tNy3G9/m5Oi98Zks0QjeHVDvuK0qfxQmPyzfmi0=
 github.com/zeebo/assert v1.3.1 h1:vukIABvugfNMZMQO1ABsyQDJDTVQbn+LWSMy1ol1h6A=

pkg/templating/markdownrenderer/html.go

@@ -0,0 +1,17 @@
+package markdownrenderer
+
+import (
+	"bytes"
+	"context"
+
+	"github.com/SigNoz/signoz/pkg/errors"
+)
+
+func (r *renderer) renderHTML(_ context.Context, markdown string) (string, error) {
+	var buf bytes.Buffer
+	if err := newHTMLRenderer().Convert([]byte(markdown), &buf); err != nil {
+		return "", errors.WrapInternalf(err, errors.CodeInternal, "failed to convert markdown to HTML")
+	}
+
+	return buf.String(), nil
+}

pkg/templating/markdownrenderer/html_test.go

@@ -0,0 +1,180 @@
+package markdownrenderer
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	testMarkdown = `# 🔥 FIRING: High CPU Usage on api-gateway
+
+https://signoz.example.com/alerts/123
+https://runbooks.example.com/cpu-high
+
+## Alert Details
+
+**Status:** **FIRING** | *api-gateway* service is experiencing high CPU usage. ~~resolved~~ previously.
+
+Alert triggered because ` + "`cpu_usage_percent`" + ` exceeded threshold ` + "`90`" + `.
+
+[View Alert in SigNoz](https://signoz.example.com/alerts/123) | [View Logs](https://signoz.example.com/logs?service=api-gateway) | [View Traces](https://signoz.example.com/traces?service=api-gateway)
+
+![critical](https://signoz.example.com/badges/critical.svg "Critical Alert")
+
+## Alert Labels
+
+| Label    | Value       |
+| -------- | ----------- |
+| service  | api-gateway |
+| instance | pod-5a8b3c  |
+| severity | critical    |
+| region   | us-east-1   |
+
+## Remediation Steps
+
+1. Check current CPU usage on the pod
+2. Review recent deployments for regressions
+3. Scale horizontally if load-related
+    1. Increase replica count
+    2. Verify HPA configuration
+
+## Affected Services
+
+* api-gateway
+* auth-service
+* payment-service
+    * payment-processor
+    * payment-validator
+
+## Incident Checklist
+
+- [x] Alert acknowledged
+- [x] On-call notified
+- [ ] Root cause identified
+- [ ] Fix deployed
+
+## Alert Rule Description
+
+> This alert fires when CPU usage exceeds 90% for more than 5 minutes on any pod in the api-gateway service.
+>
+>> For capacity planning guidelines, see the infrastructure runbook section on horizontal pod autoscaling.
+
+## Triggered Query
+` + "```promql\navg(rate(container_cpu_usage_seconds_total{service=\"api-gateway\"}[5m])) by (pod) > 0.9\n```" + `
+
+## Inline Details
+
+This alert was generated by SigNoz using ` + "`alertmanager`" + ` rules engine.
+`
+)
+
+func newTestRenderer() Renderer {
+	return NewRenderer()
+}
+
+func TestRenderHTML_Composite(t *testing.T) {
+	renderer := newTestRenderer()
+
+	html, err := renderer.Render(context.Background(), testMarkdown, MarkdownFormatHTML)
+	require.NoError(t, err)
+
+	// Full expected output for exact match
+	expected := "<h1>🔥 FIRING: High CPU Usage on api-gateway</h1>\n" +
+		"<p><a href=\"https://signoz.example.com/alerts/123\">https://signoz.example.com/alerts/123</a>\n<a href=\"https://runbooks.example.com/cpu-high\">https://runbooks.example.com/cpu-high</a></p>\n" +
+		"<h2>Alert Details</h2>\n" +
+		"<p><strong>Status:</strong> <strong>FIRING</strong> | <em>api-gateway</em> service is experiencing high CPU usage. <del>resolved</del> previously.</p>\n" +
+		"<p>Alert triggered because <code>cpu_usage_percent</code> exceeded threshold <code>90</code>.</p>\n" +
+		"<p><a href=\"https://signoz.example.com/alerts/123\">View Alert in SigNoz</a> | <a href=\"https://signoz.example.com/logs?service=api-gateway\">View Logs</a> | <a href=\"https://signoz.example.com/traces?service=api-gateway\">View Traces</a></p>\n" +
+		"<p><img src=\"https://signoz.example.com/badges/critical.svg\" alt=\"critical\" title=\"Critical Alert\"></p>\n" +
+		"<h2>Alert Labels</h2>\n" +
+		"<table>\n<thead>\n<tr>\n<th>Label</th>\n<th>Value</th>\n</tr>\n</thead>\n" +
+		"<tbody>\n<tr>\n<td>service</td>\n<td>api-gateway</td>\n</tr>\n" +
+		"<tr>\n<td>instance</td>\n<td>pod-5a8b3c</td>\n</tr>\n" +
+		"<tr>\n<td>severity</td>\n<td>critical</td>\n</tr>\n" +
+		"<tr>\n<td>region</td>\n<td>us-east-1</td>\n</tr>\n</tbody>\n</table>\n" +
+		"<h2>Remediation Steps</h2>\n" +
+		"<ol>\n<li>Check current CPU usage on the pod</li>\n<li>Review recent deployments for regressions</li>\n<li>Scale horizontally if load-related\n" +
+		"<ol>\n<li>Increase replica count</li>\n<li>Verify HPA configuration</li>\n</ol>\n</li>\n</ol>\n" +
+		"<h2>Affected Services</h2>\n" +
+		"<ul>\n<li>api-gateway</li>\n<li>auth-service</li>\n<li>payment-service\n" +
+		"<ul>\n<li>payment-processor</li>\n<li>payment-validator</li>\n</ul>\n</li>\n</ul>\n" +
+		"<h2>Incident Checklist</h2>\n" +
+		"<ul>\n<li><input checked=\"\" disabled=\"\" type=\"checkbox\"> Alert acknowledged</li>\n" +
+		"<li><input checked=\"\" disabled=\"\" type=\"checkbox\"> On-call notified</li>\n" +
+		"<li><input disabled=\"\" type=\"checkbox\"> Root cause identified</li>\n" +
+		"<li><input disabled=\"\" type=\"checkbox\"> Fix deployed</li>\n</ul>\n" +
+		"<h2>Alert Rule Description</h2>\n" +
+		"<blockquote>\n<p>This alert fires when CPU usage exceeds 90% for more than 5 minutes on any pod in the api-gateway service.</p>\n" +
+		"<blockquote>\n<p>For capacity planning guidelines, see the infrastructure runbook section on horizontal pod autoscaling.</p>\n</blockquote>\n</blockquote>\n" +
+		"<h2>Triggered Query</h2>\n" +
+		"<pre><code class=\"language-promql\">avg(rate(container_cpu_usage_seconds_total{service=&quot;api-gateway&quot;}[5m])) by (pod) &gt; 0.9\n</code></pre>\n" +
+		"<h2>Inline Details</h2>\n" +
+		"<p>This alert was generated by SigNoz using <code>alertmanager</code> rules engine.</p>\n"
+
+	assert.Equal(t, expected, html)
+}
+
+func TestRenderHTML_InlineFormatting(t *testing.T) {
+	renderer := newTestRenderer()
+
+	input := `# 🔥 FIRING: High CPU on api-gateway
+## Alert Status
+
+**FIRING** alert for *api-gateway* service — ~~resolved~~ previously.
+
+Metric ` + "`cpu_usage_percent`" + ` exceeded threshold. [View in SigNoz](https://signoz.example.com/alerts/123)
+
+![critical](https://signoz.example.com/badges/critical.svg "Critical Alert")`
+
+	html, err := renderer.Render(context.Background(), input, MarkdownFormatHTML)
+	require.NoError(t, err)
+
+	expected := "<h1>🔥 FIRING: High CPU on api-gateway</h1>\n<h2>Alert Status</h2>\n" +
+		"<p><strong>FIRING</strong> alert for <em>api-gateway</em> service — <del>resolved</del> previously.</p>\n" +
+		"<p>Metric <code>cpu_usage_percent</code> exceeded threshold. <a href=\"https://signoz.example.com/alerts/123\">View in SigNoz</a></p>\n" +
+		"<p><img src=\"https://signoz.example.com/badges/critical.svg\" alt=\"critical\" title=\"Critical Alert\"></p>\n"
+
+	assert.Equal(t, expected, html)
+}
+
+func TestRenderHTML_BlockElements(t *testing.T) {
+	renderer := newTestRenderer()
+
+	input := `1. Check CPU usage on the pod
+2. Review recent deployments
+3. Scale horizontally if needed
+
+* api-gateway
+* auth-service
+* payment-service
+
+- [x] Alert acknowledged
+- [ ] Root cause identified
+
+> This alert fires when CPU usage exceeds 90% for more than 5 minutes.
+
+| Label    | Value       |
+| -------- | ----------- |
+| service  | api-gateway |
+| severity | <no value>    |
+
+` + "```promql\navg(rate(container_cpu_usage_seconds_total{service=\"api-gateway\"}[5m])) by (pod) > 0.9\n```"
+
+	html, err := renderer.Render(context.Background(), input, MarkdownFormatHTML)
+	require.NoError(t, err)
+
+	expected := "<ol>\n<li>Check CPU usage on the pod</li>\n<li>Review recent deployments</li>\n<li>Scale horizontally if needed</li>\n</ol>\n" +
+		"<ul>\n<li>api-gateway</li>\n<li>auth-service</li>\n<li>payment-service</li>\n</ul>\n" +
+		"<ul>\n<li><input checked=\"\" disabled=\"\" type=\"checkbox\"> Alert acknowledged</li>\n" +
+		"<li><input disabled=\"\" type=\"checkbox\"> Root cause identified</li>\n</ul>\n" +
+		"<blockquote>\n<p>This alert fires when CPU usage exceeds 90% for more than 5 minutes.</p>\n</blockquote>\n" +
+		"<table>\n<thead>\n<tr>\n<th>Label</th>\n<th>Value</th>\n</tr>\n</thead>\n" +
+		"<tbody>\n<tr>\n<td>service</td>\n<td>api-gateway</td>\n</tr>\n" +
+		"<tr>\n<td>severity</td>\n<td>&lt;no value&gt;</td>\n</tr>\n</tbody>\n</table>\n" +
+		"<pre><code class=\"language-promql\">avg(rate(container_cpu_usage_seconds_total{service=&quot;api-gateway&quot;}[5m])) by (pod) &gt; 0.9\n</code></pre>\n"
+
+	assert.Equal(t, expected, html)
+}

pkg/templating/markdownrenderer/markdownrenderer.go

@@ -0,0 +1,71 @@
+package markdownrenderer
+
+import (
+	"context"
+
+	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/templating/slackblockkitrenderer"
+	"github.com/SigNoz/signoz/pkg/templating/slackmrkdwnrenderer"
+	"github.com/SigNoz/signoz/pkg/templating/templatingextensions"
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/extension"
+)
+
+// newHTMLRenderer creates a new goldmark.Markdown instance for HTML rendering.
+func newHTMLRenderer() goldmark.Markdown {
+	return goldmark.New(
+		goldmark.WithExtensions(extension.GFM),
+		goldmark.WithExtensions(templatingextensions.EscapeNoValue),
+	)
+}
+
+// newSlackBlockKitRenderer creates a new goldmark.Markdown instance for Slack Block Kit rendering.
+func newSlackBlockKitRenderer() goldmark.Markdown {
+	return goldmark.New(
+		goldmark.WithExtensions(slackblockkitrenderer.BlockKitV2),
+	)
+}
+
+// newSlackMrkdwnRenderer creates a new goldmark.Markdown instance for Slack mrkdwn rendering.
+func newSlackMrkdwnRenderer() goldmark.Markdown {
+	return goldmark.New(
+		goldmark.WithExtensions(slackmrkdwnrenderer.SlackMrkdwn),
+	)
+}
+
+type OutputFormat int
+
+const (
+	MarkdownFormatHTML OutputFormat = iota
+	MarkdownFormatSlackBlockKit
+	MarkdownFormatSlackMrkdwn
+	MarkdownFormatNoop
+)
+
+// Renderer is the interface for rendering markdown to different formats.
+type Renderer interface {
+	// Render renders the markdown to the given output format.
+	Render(ctx context.Context, markdown string, outputFormat OutputFormat) (string, error)
+}
+
+type renderer struct {
+}
+
+func NewRenderer() Renderer {
+	return &renderer{}
+}
+
+func (r *renderer) Render(ctx context.Context, markdown string, outputFormat OutputFormat) (string, error) {
+	switch outputFormat {
+	case MarkdownFormatHTML:
+		return r.renderHTML(ctx, markdown)
+	case MarkdownFormatSlackBlockKit:
+		return r.renderSlackBlockKit(ctx, markdown)
+	case MarkdownFormatSlackMrkdwn:
+		return r.renderSlackMrkdwn(ctx, markdown)
+	case MarkdownFormatNoop:
+		return markdown, nil
+	default:
+		return "", errors.NewInvalidInputf(errors.CodeInvalidInput, "unknown output format: %v", outputFormat)
+	}
+}

pkg/templating/markdownrenderer/noop_test.go

@@ -0,0 +1,17 @@
+package markdownrenderer
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRenderNoop(t *testing.T) {
+	renderer := newTestRenderer()
+
+	output, err := renderer.Render(context.Background(), testMarkdown, MarkdownFormatNoop)
+	require.NoError(t, err)
+	assert.Equal(t, testMarkdown, output)
+}

pkg/templating/markdownrenderer/slack.go

@@ -0,0 +1,24 @@
+package markdownrenderer
+
+import (
+	"bytes"
+	"context"
+
+	"github.com/SigNoz/signoz/pkg/errors"
+)
+
+func (r *renderer) renderSlackBlockKit(_ context.Context, markdown string) (string, error) {
+	var buf bytes.Buffer
+	if err := newSlackBlockKitRenderer().Convert([]byte(markdown), &buf); err != nil {
+		return "", errors.WrapInternalf(err, errors.CodeInternal, "failed to convert markdown to Slack Block Kit")
+	}
+	return buf.String(), nil
+}
+
+func (r *renderer) renderSlackMrkdwn(_ context.Context, markdown string) (string, error) {
+	var buf bytes.Buffer
+	if err := newSlackMrkdwnRenderer().Convert([]byte(markdown), &buf); err != nil {
+		return "", errors.WrapInternalf(err, errors.CodeInternal, "failed to convert markdown to Slack Mrkdwn")
+	}
+	return buf.String(), nil
+}

pkg/templating/markdownrenderer/slack_test.go

@@ -0,0 +1,151 @@
+package markdownrenderer
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+)
+
+func jsonEqual(a, b string) bool {
+	var va, vb any
+	if err := json.Unmarshal([]byte(a), &va); err != nil {
+		return false
+	}
+	if err := json.Unmarshal([]byte(b), &vb); err != nil {
+		return false
+	}
+	ja, _ := json.Marshal(va)
+	jb, _ := json.Marshal(vb)
+	return string(ja) == string(jb)
+}
+
+func prettyJSON(s string) string {
+	var v any
+	if err := json.Unmarshal([]byte(s), &v); err != nil {
+		return s
+	}
+	b, _ := json.MarshalIndent(v, "", "  ")
+	return string(b)
+}
+
+func TestRenderSlackBlockKit(t *testing.T) {
+	renderer := NewRenderer()
+
+	tests := []struct {
+		name     string
+		markdown string
+		expected string
+	}{
+		{
+			name:     "simple paragraph",
+			markdown: "Hello world",
+			expected: `[
+				{
+					"type": "section",
+					"text": { "type": "mrkdwn", "text": "Hello world" }
+				}
+			]`,
+		},
+		{
+			name: "alert-themed with heading, list, and code block",
+			markdown: `# Alert Triggered
+
+- Service: **checkout-api**
+- Status: _critical_
+
+` + "```" + `
+error: connection timeout after 30s
+` + "```",
+			expected: `[
+				{
+					"type": "section",
+					"text": { "type": "mrkdwn", "text": "*Alert Triggered*" }
+				},
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "bullet", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [
+									{ "type": "text", "text": "Service: " },
+									{ "type": "text", "text": "checkout-api", "style": { "bold": true } }
+								]},
+								{ "type": "rich_text_section", "elements": [
+									{ "type": "text", "text": "Status: " },
+									{ "type": "text", "text": "critical", "style": { "italic": true } }
+								]}
+							]
+						}
+					]
+				},
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_preformatted",
+							"border": 0,
+							"elements": [
+								{ "type": "text", "text": "error: connection timeout after 30s" }
+							]
+						}
+					]
+				}
+			]`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := renderer.Render(context.Background(), tt.markdown, MarkdownFormatSlackBlockKit)
+			if err != nil {
+				t.Fatalf("Render error: %v", err)
+			}
+
+			// Verify output is valid JSON
+			if !json.Valid([]byte(got)) {
+				t.Fatalf("output is not valid JSON:\n%s", got)
+			}
+
+			if !jsonEqual(got, tt.expected) {
+				t.Errorf("JSON mismatch\n\nMarkdown:\n%s\n\nExpected:\n%s\n\nGot:\n%s",
+					tt.markdown, prettyJSON(tt.expected), prettyJSON(got))
+			}
+		})
+	}
+}
+
+func TestRenderSlackMrkdwn(t *testing.T) {
+	renderer := NewRenderer()
+
+	markdown := `# Alert Triggered
+
+- Service: **checkout-api**
+- Status: _critical_
+- Dashboard: [View Dashboard](https://example.com/dashboard)
+
+| Metric | Value | Threshold |
+| --- | --- | --- |
+| Latency | 250ms | 100ms |
+| Error Rate | 5.2% | 1% |
+
+` + "```" + `
+error: connection timeout after 30s
+` + "```"
+
+	expected := "*Alert Triggered*\n\n" +
+		"• Service: *checkout-api*\n" +
+		"• Status: _critical_\n" +
+		"• Dashboard: <https://example.com/dashboard|View Dashboard>\n\n" +
+		"```\nMetric     | Value | Threshold\n-----------|-------|----------\nLatency    | 250ms | 100ms    \nError Rate | 5.2%  | 1%       \n```\n\n" +
+		"```\nerror: connection timeout after 30s\n```\n\n"
+
+	got, err := renderer.Render(context.Background(), markdown, MarkdownFormatSlackMrkdwn)
+	if err != nil {
+		t.Fatalf("Render error: %v", err)
+	}
+
+	if got != expected {
+		t.Errorf("mrkdwn mismatch\n\nExpected:\n%q\n\nGot:\n%q", expected, got)
+	}
+}

pkg/templating/slackblockkitrenderer/extender.go

@@ -0,0 +1,23 @@
+package slackblockkitrenderer
+
+import (
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/extension"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/util"
+)
+
+type blockKitV2 struct{}
+
+// BlockKitV2 is a goldmark.Extender that configures the Slack Block Kit v2 renderer.
+var BlockKitV2 = &blockKitV2{}
+
+// Extend implements goldmark.Extender.
+func (e *blockKitV2) Extend(m goldmark.Markdown) {
+	extension.Table.Extend(m)
+	extension.Strikethrough.Extend(m)
+	extension.TaskList.Extend(m)
+	m.Renderer().AddOptions(
+		renderer.WithNodeRenderers(util.Prioritized(NewRenderer(), 1)),
+	)
+}

pkg/templating/slackblockkitrenderer/renderer_test.go

@@ -0,0 +1,542 @@
+package slackblockkitrenderer
+
+import (
+	"bytes"
+	"encoding/json"
+	"testing"
+
+	"github.com/yuin/goldmark"
+)
+
+func jsonEqual(a, b string) bool {
+	var va, vb interface{}
+	if err := json.Unmarshal([]byte(a), &va); err != nil {
+		return false
+	}
+	if err := json.Unmarshal([]byte(b), &vb); err != nil {
+		return false
+	}
+	ja, _ := json.Marshal(va)
+	jb, _ := json.Marshal(vb)
+	return string(ja) == string(jb)
+}
+
+func prettyJSON(s string) string {
+	var v interface{}
+	if err := json.Unmarshal([]byte(s), &v); err != nil {
+		return s
+	}
+	b, _ := json.MarshalIndent(v, "", "  ")
+	return string(b)
+}
+
+func TestRenderer(t *testing.T) {
+	tests := []struct {
+		name     string
+		markdown string
+		expected string
+	}{
+		{
+			name:     "empty input",
+			markdown: "",
+			expected: `[]`,
+		},
+		{
+			name:     "simple paragraph",
+			markdown: "Hello world",
+			expected: `[
+				{
+					"type": "section",
+					"text": { "type": "mrkdwn", "text": "Hello world" }
+				}
+			]`,
+		},
+		{
+			name:     "heading",
+			markdown: "# My Heading",
+			expected: `[
+				{
+					"type": "section",
+					"text": { "type": "mrkdwn", "text": "*My Heading*" }
+				}
+			]`,
+		},
+		{
+			name:     "multiple paragraphs",
+			markdown: "First paragraph\n\nSecond paragraph",
+			expected: `[
+				{
+					"type": "section",
+					"text": { "type": "mrkdwn", "text": "First paragraph\nSecond paragraph" }
+				}
+			]`,
+		},
+		{
+			name:     "todo list ",
+			markdown: "- [ ] item 1\n- [x] item 2",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+					{ 
+						"border": 0, 
+						"elements": [ 
+							{ "elements": [ { "text": "[ ] ", "type": "text" }, { "text": "item 1", "type": "text" } ], "type": "rich_text_section" }, 
+							{ "elements": [ { "text": "[x] ", "type": "text" }, { "text": "item 2", "type": "text" } ], "type": "rich_text_section" } 
+						],
+						"indent": 0, 
+						"style": "bullet", 
+						"type": "rich_text_list" 
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "thematic break between paragraphs",
+			markdown: "Before\n\n---\n\nAfter",
+			expected: `[
+				{ "type": "section", "text": { "type": "mrkdwn", "text": "Before" } },
+				{ "type": "divider" },
+				{ "type": "section", "text": { "type": "mrkdwn", "text": "After" } }
+			]`,
+		},
+		{
+			name:     "fenced code block with language",
+			markdown: "```go\nfmt.Println(\"hello\")\n```",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_preformatted",
+							"border": 0,
+							"language": "go",
+							"elements": [
+								{ "type": "text", "text": "fmt.Println(\"hello\")" }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "indented code block",
+			markdown: "    code line 1\n    code line 2",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_preformatted",
+							"border": 0,
+							"elements": [
+								{ "type": "text", "text": "code line 1\ncode line 2" }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "empty fenced code block",
+			markdown: "```\n```",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_preformatted",
+							"border": 0,
+							"elements": [
+								{ "type": "text", "text": " " }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "simple bullet list",
+			markdown: "- item 1\n- item 2\n- item 3",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "bullet", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "item 1" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "item 2" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "item 3" }] }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "simple ordered list",
+			markdown: "1. first\n2. second\n3. third",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "ordered", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "first" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "second" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "third" }] }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "nested bullet list (2 levels)",
+			markdown: "- item 1\n- item 2\n  - sub a\n  - sub b\n- item 3",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "bullet", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "item 1" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "item 2" }] }
+							]
+						},
+						{
+							"type": "rich_text_list", "style": "bullet", "indent": 1, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "sub a" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "sub b" }] }
+							]
+						},
+						{
+							"type": "rich_text_list", "style": "bullet", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "item 3" }] }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "nested ordered list with offset",
+			markdown: "1. first\n   1. nested-a\n   2. nested-b\n2. second\n3. third",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "ordered", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "first" }] }
+							]
+						},
+						{
+							"type": "rich_text_list", "style": "ordered", "indent": 1, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "nested-a" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "nested-b" }] }
+							]
+						},
+						{
+							"type": "rich_text_list", "style": "ordered", "indent": 0, "border": 0, "offset": 1,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "second" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "third" }] }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "mixed ordered/bullet nesting",
+			markdown: "1. ordered\n   - bullet child\n2. ordered again",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "ordered", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "ordered" }] }
+							]
+						},
+						{
+							"type": "rich_text_list", "style": "bullet", "indent": 1, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "bullet child" }] }
+							]
+						},
+						{
+							"type": "rich_text_list", "style": "ordered", "indent": 0, "border": 0, "offset": 1,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "ordered again" }] }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "list items with bold/italic/link/code",
+			markdown: "- **bold item**\n- _italic item_\n- [link](http://example.com)\n- `code item`",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "bullet", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "bold item", "style": { "bold": true } }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "italic item", "style": { "italic": true } }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "link", "url": "http://example.com", "text": "link" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "code item", "style": { "code": true } }] }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "table with header and body",
+			markdown: "| Name | Age |\n|------|-----|\n| Alice | 30 |",
+			expected: `[
+				{
+					"type": "table",
+					"rows": [
+						[
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "Name", "style": { "bold": true } }] }
+							]},
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "Age", "style": { "bold": true } }] }
+							]}
+						],
+						[
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "Alice" }] }
+							]},
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "30" }] }
+							]}
+						]
+					]
+				}
+			]`,
+		},
+		{
+			name:     "blockquote",
+			markdown: "> quoted text",
+			expected: `[
+				{
+					"type": "section",
+					"text": { "type": "mrkdwn", "text": "> quoted text" }
+				}
+			]`,
+		},
+		{
+			name:     "blockquote with nested list",
+			markdown: "> item 1\n> > item 2\n> > item 3",
+			expected: `[
+				{
+					"text": {
+					"text": "> item 1\n> > item 2\n> > item 3",
+					"type": "mrkdwn"
+					},
+					"type": "section"
+				}
+			]`,
+		},
+		{
+			name:     "inline formatting in paragraph",
+			markdown: "This is **bold** and _italic_ and ~strike~ and `code`",
+			expected: `[
+				{
+					"type": "section",
+					"text": { "type": "mrkdwn", "text": "This is *bold* and _italic_ and ~strike~ and ` + "`code`" + `" }
+				}
+			]`,
+		},
+		{
+			name:     "link in paragraph",
+			markdown: "Visit [Google](http://google.com)",
+			expected: `[
+				{
+					"type": "section",
+					"text": { "type": "mrkdwn", "text": "Visit <http://google.com|Google>" }
+				}
+			]`,
+		},
+		{
+			name:     "image is skipped",
+			markdown: "![alt](http://example.com/image.png)",
+			// For image skip the block and return empty array
+			expected: `[]`,
+		},
+		{
+			name:     "paragraph then list then paragraph",
+			markdown: "Before\n\n- item\n\nAfter",
+			expected: `[
+				{ "type": "section", "text": { "type": "mrkdwn", "text": "Before" } },
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "bullet", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "item" }] }
+							]
+						}
+					]
+				},
+				{ "type": "section", "text": { "type": "mrkdwn", "text": "After" } }
+			]`,
+		},
+		{
+			name:     "ordered list with start > 1",
+			markdown: "5. fifth\n6. sixth",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "ordered", "indent": 0, "border": 0, "offset": 4,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "fifth" }] },
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "sixth" }] }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "deeply nested ordered list (3 levels) with offsets",
+			markdown: "1. Some things\n\t1. are best left\n2. to the fate\n\t1. of the world\n\t\t1. and then\n\t\t2. this is how\n3. it turns out to be",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{ "type": "rich_text_list", "style": "ordered", "indent": 0, "border": 0,
+						  "elements": [{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "Some things" }] }] },
+
+						{ "type": "rich_text_list", "style": "ordered", "indent": 1, "border": 0,
+						  "elements": [{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "are best left" }] }] },
+
+						{ "type": "rich_text_list", "style": "ordered", "indent": 0, "border": 0, "offset": 1,
+						  "elements": [{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "to the fate" }] }] },
+
+						{ "type": "rich_text_list", "style": "ordered", "indent": 1, "border": 0,
+						  "elements": [{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "of the world" }] }] },
+
+						{ "type": "rich_text_list", "style": "ordered", "indent": 2, "border": 0,
+						  "elements": [
+						    { "type": "rich_text_section", "elements": [{ "type": "text", "text": "and then" }] },
+						    { "type": "rich_text_section", "elements": [{ "type": "text", "text": "this is how" }] }
+						  ]
+						},
+
+						{ "type": "rich_text_list", "style": "ordered", "indent": 0, "border": 0, "offset": 2,
+						  "elements": [{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "it turns out to be" }] }] }
+					]
+				}
+			]`,
+		},
+		{
+			name:     "link with bold label in list item",
+			markdown: "- [**docs**](http://example.com)",
+			expected: `[
+				{
+					"type": "rich_text",
+					"elements": [
+						{
+							"type": "rich_text_list", "style": "bullet", "indent": 0, "border": 0,
+							"elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "link", "url": "http://example.com", "text": "docs" }] }
+							]
+						}
+					]
+				}
+			]`,
+		},
+		{
+			name:     "table with empty cell",
+			markdown: "| A | B |\n|---|---|\n| 1 | |",
+			expected: `[
+				{
+					"type": "table",
+					"rows": [
+						[
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "A", "style": { "bold": true } }] }
+							]},
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "B", "style": { "bold": true } }] }
+							]}
+						],
+						[
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "1" }] }
+							]},
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": " " }] }
+							]}
+						]
+					]
+				}
+			]`,
+		},
+		{
+			name:     "table with missing column in row",
+			markdown: "| A | B |\n|---|---|\n| 1 |",
+			expected: `[
+				{
+					"type": "table",
+					"rows": [
+						[
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "A", "style": { "bold": true } }] }
+							]},
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "B", "style": { "bold": true } }] }
+							]}
+						],
+						[
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": "1" }] }
+							]},
+							{ "type": "rich_text", "elements": [
+								{ "type": "rich_text_section", "elements": [{ "type": "text", "text": " " }] }
+							]}
+						]
+					]
+				}
+			]`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			md := goldmark.New(
+				goldmark.WithExtensions(BlockKitV2),
+			)
+			var buf bytes.Buffer
+			if err := md.Convert([]byte(tt.markdown), &buf); err != nil {
+				t.Fatalf("convert error: %v", err)
+			}
+			got := buf.String()
+			if !jsonEqual(got, tt.expected) {
+				t.Errorf("JSON mismatch\n\nMarkdown:\n%s\n\nExpected:\n%s\n\nGot:\n%s",
+					tt.markdown, prettyJSON(tt.expected), prettyJSON(got))
+			}
+		})
+	}
+}

pkg/templating/slackblockkitrenderer/slackblockkitrenderer.go

@@ -0,0 +1,737 @@
+package slackblockkitrenderer
+
+import (
+	"bytes"
+	"encoding/json"
+	"strings"
+
+	"github.com/yuin/goldmark/ast"
+	extensionast "github.com/yuin/goldmark/extension/ast"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/util"
+)
+
+// listFrame tracks state for a single level of list nesting.
+type listFrame struct {
+	style     string // "bullet" or "ordered"
+	indent    int
+	itemCount int
+}
+
+// listContext holds all state while processing a list tree.
+type listContext struct {
+	result             []RichTextList
+	stack              []listFrame
+	current            *RichTextList
+	currentItemInlines []interface{}
+}
+
+// tableContext holds state while processing a table.
+type tableContext struct {
+	rows               [][]TableCell
+	currentRow         []TableCell
+	currentCellInlines []interface{}
+	isHeader           bool
+}
+
+// Renderer converts Markdown AST to Slack Block Kit JSON.
+type Renderer struct {
+	blocks []interface{}
+	mrkdwn strings.Builder
+	// holds active styles for the current rich text element
+	styleStack []RichTextStyle
+	// holds the current list context while processing a list tree.
+	listCtx *listContext
+	// holds the current table context while processing a table.
+	tableCtx *tableContext
+	// stores the current blockquote depth while processing a blockquote.
+	// so blockquote with nested list can be rendered correctly.
+	blockquoteDepth int
+}
+
+// NewRenderer returns a new block kit renderer.
+func NewRenderer() renderer.NodeRenderer {
+	return &Renderer{}
+}
+
+// RegisterFuncs registers node rendering functions.
+func (r *Renderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+	// Blocks
+	reg.Register(ast.KindDocument, r.renderDocument)
+	reg.Register(ast.KindHeading, r.renderHeading)
+	reg.Register(ast.KindParagraph, r.renderParagraph)
+	reg.Register(ast.KindThematicBreak, r.renderThematicBreak)
+	reg.Register(ast.KindCodeBlock, r.renderCodeBlock)
+	reg.Register(ast.KindFencedCodeBlock, r.renderFencedCodeBlock)
+	reg.Register(ast.KindBlockquote, r.renderBlockquote)
+	reg.Register(ast.KindList, r.renderList)
+	reg.Register(ast.KindListItem, r.renderListItem)
+	reg.Register(ast.KindImage, r.renderImage)
+
+	// Inlines
+	reg.Register(ast.KindText, r.renderText)
+	reg.Register(ast.KindEmphasis, r.renderEmphasis)
+	reg.Register(ast.KindCodeSpan, r.renderCodeSpan)
+	reg.Register(ast.KindLink, r.renderLink)
+
+	// Extensions
+	reg.Register(extensionast.KindStrikethrough, r.renderStrikethrough)
+	reg.Register(extensionast.KindTable, r.renderTable)
+	reg.Register(extensionast.KindTableHeader, r.renderTableHeader)
+	reg.Register(extensionast.KindTableRow, r.renderTableRow)
+	reg.Register(extensionast.KindTableCell, r.renderTableCell)
+	reg.Register(extensionast.KindTaskCheckBox, r.renderTaskCheckBox)
+}
+
+// inRichTextMode returns true when we're inside a list or table context
+// in slack blockkit list and table items are rendered as rich_text elements
+// if more cases are found in future those needs to be added here.
+func (r *Renderer) inRichTextMode() bool {
+	return r.listCtx != nil || r.tableCtx != nil
+}
+
+// currentStyle merges the stored style stack into RichTextStyle
+// which can be applied on rich text elements.
+func (r *Renderer) currentStyle() *RichTextStyle {
+	s := RichTextStyle{}
+	for _, f := range r.styleStack {
+		s.Bold = s.Bold || f.Bold
+		s.Italic = s.Italic || f.Italic
+		s.Strike = s.Strike || f.Strike
+		s.Code = s.Code || f.Code
+	}
+	if s == (RichTextStyle{}) {
+		return nil
+	}
+	return &s
+}
+
+// flushMrkdwn collects markdown text and adds it as a SectionBlock with mrkdwn text
+// whenever starting a new block we flush markdown to render it as a separate block.
+func (r *Renderer) flushMrkdwn() {
+	text := strings.TrimSpace(r.mrkdwn.String())
+	if text != "" {
+		r.blocks = append(r.blocks, SectionBlock{
+			Type: "section",
+			Text: &TextObject{
+				Type: "mrkdwn",
+				Text: text,
+			},
+		})
+	}
+	r.mrkdwn.Reset()
+}
+
+// addInline adds an inline element to the appropriate context.
+func (r *Renderer) addInline(el interface{}) {
+	if r.listCtx != nil {
+		r.listCtx.currentItemInlines = append(r.listCtx.currentItemInlines, el)
+	} else if r.tableCtx != nil {
+		r.tableCtx.currentCellInlines = append(r.tableCtx.currentCellInlines, el)
+	}
+}
+
+// --- Document ---
+
+func (r *Renderer) renderDocument(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.blocks = nil
+		r.mrkdwn.Reset()
+		r.styleStack = nil
+		r.listCtx = nil
+		r.tableCtx = nil
+		r.blockquoteDepth = 0
+	} else {
+		// on exiting the document node write the json for the collected blocks.
+		r.flushMrkdwn()
+		var data []byte
+		var err error
+		if len(r.blocks) > 0 {
+			data, err = json.Marshal(r.blocks)
+			if err != nil {
+				return ast.WalkStop, err
+			}
+		} else {
+			// if no blocks are collected, write an empty array.
+			data = []byte("[]")
+		}
+		_, err = w.Write(data)
+		if err != nil {
+			return ast.WalkStop, err
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- Heading ---
+
+func (r *Renderer) renderHeading(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.mrkdwn.WriteString("*")
+	} else {
+		r.mrkdwn.WriteString("*\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- Paragraph ---
+
+func (r *Renderer) renderParagraph(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		if r.mrkdwn.Len() > 0 {
+			text := r.mrkdwn.String()
+			if !strings.HasSuffix(text, "\n") {
+				r.mrkdwn.WriteString("\n")
+			}
+		}
+		// handling of nested blockquotes
+		if r.blockquoteDepth > 0 {
+			r.mrkdwn.WriteString(strings.Repeat("> ", r.blockquoteDepth))
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- ThematicBreak ---
+
+func (r *Renderer) renderThematicBreak(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.flushMrkdwn()
+		r.blocks = append(r.blocks, DividerBlock{Type: "divider"})
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- CodeBlock (indented) ---
+
+func (r *Renderer) renderCodeBlock(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	r.flushMrkdwn()
+
+	var buf bytes.Buffer
+	lines := node.Lines()
+	for i := 0; i < lines.Len(); i++ {
+		line := lines.At(i)
+		buf.Write(line.Value(source))
+	}
+
+	text := buf.String()
+	// Remove trailing newline
+	text = strings.TrimRight(text, "\n")
+	// Slack API rejects empty text in rich_text_preformatted elements
+	if text == "" {
+		text = " "
+	}
+
+	elements := []interface{}{
+		RichTextInline{Type: "text", Text: text},
+	}
+
+	r.blocks = append(r.blocks, RichTextBlock{
+		Type: "rich_text",
+		Elements: []interface{}{
+			RichTextPreformatted{
+				Type:     "rich_text_preformatted",
+				Elements: elements,
+				Border:   0,
+			},
+		},
+	})
+	return ast.WalkContinue, nil
+}
+
+// --- FencedCodeBlock ---
+
+func (r *Renderer) renderFencedCodeBlock(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	r.flushMrkdwn()
+
+	n := node.(*ast.FencedCodeBlock)
+	var buf bytes.Buffer
+	lines := node.Lines()
+	for i := 0; i < lines.Len(); i++ {
+		line := lines.At(i)
+		buf.Write(line.Value(source))
+	}
+
+	text := buf.String()
+	text = strings.TrimRight(text, "\n")
+	// Slack API rejects empty text in rich_text_preformatted elements
+	if text == "" {
+		text = " "
+	}
+
+	elements := []interface{}{
+		RichTextInline{Type: "text", Text: text},
+	}
+
+	// If language is specified, collect it.
+	var language string
+	lang := n.Language(source)
+	if len(lang) > 0 {
+		language = string(lang)
+	}
+	// Add the preformatted block to the blocks slice with the collected language.
+	r.blocks = append(r.blocks, RichTextBlock{
+		Type: "rich_text",
+		Elements: []interface{}{
+			RichTextPreformatted{
+				Type:     "rich_text_preformatted",
+				Elements: elements,
+				Border:   0,
+				Language: language,
+			},
+		},
+	})
+
+	return ast.WalkSkipChildren, nil
+}
+
+// --- Blockquote ---
+
+func (r *Renderer) renderBlockquote(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.blockquoteDepth++
+	} else {
+		r.blockquoteDepth--
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- List ---
+
+func (r *Renderer) renderList(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	list := node.(*ast.List)
+
+	if entering {
+		style := "bullet"
+		if list.IsOrdered() {
+			style = "ordered"
+		}
+
+		if r.listCtx == nil {
+			// Top-level list: flush mrkdwn and create context
+			r.flushMrkdwn()
+			r.listCtx = &listContext{}
+		} else {
+			// Nested list: check if we already have some collected list items that needs to be flushed.
+			// in slack blockkit, list items with different levels of indentation are added as different rich_text_list blocks.
+			if len(r.listCtx.currentItemInlines) > 0 {
+				sec := RichTextBlock{
+					Type:     "rich_text_section",
+					Elements: r.listCtx.currentItemInlines,
+				}
+				if r.listCtx.current != nil {
+					r.listCtx.current.Elements = append(r.listCtx.current.Elements, sec)
+				}
+				r.listCtx.currentItemInlines = nil
+				// Increment parent's itemCount
+				if len(r.listCtx.stack) > 0 {
+					r.listCtx.stack[len(r.listCtx.stack)-1].itemCount++
+				}
+			}
+			// Finalize current list to result only if items were collected
+			if r.listCtx.current != nil && len(r.listCtx.current.Elements) > 0 {
+				r.listCtx.result = append(r.listCtx.result, *r.listCtx.current)
+			}
+		}
+
+		// the stack accumulated till this level derives hte indentation
+		// the stack get's collected as we go in more nested levels of list
+		// and as we get our of the nesting we remove the items from the slack
+		indent := len(r.listCtx.stack)
+		r.listCtx.stack = append(r.listCtx.stack, listFrame{
+			style:     style,
+			indent:    indent,
+			itemCount: 0,
+		})
+
+		newList := &RichTextList{
+			Type:     "rich_text_list",
+			Style:    style,
+			Indent:   indent,
+			Border:   0,
+			Elements: []interface{}{},
+		}
+
+		// Handle ordered list with start > 1
+		if list.IsOrdered() && list.Start > 1 {
+			newList.Offset = list.Start - 1
+		}
+
+		r.listCtx.current = newList
+
+	} else {
+		// Leaving list: finalize current list
+		if r.listCtx.current != nil && len(r.listCtx.current.Elements) > 0 {
+			r.listCtx.result = append(r.listCtx.result, *r.listCtx.current)
+		}
+
+		// Pop stack to so upcoming indentations can be handled correctly.
+		r.listCtx.stack = r.listCtx.stack[:len(r.listCtx.stack)-1]
+
+		if len(r.listCtx.stack) > 0 {
+			// Resume parent: start a new list segment at parent indent/style
+			parent := &r.listCtx.stack[len(r.listCtx.stack)-1]
+			newList := &RichTextList{
+				Type:     "rich_text_list",
+				Style:    parent.style,
+				Indent:   parent.indent,
+				Border:   0,
+				Elements: []interface{}{},
+			}
+			// Set offset for ordered parent continuation
+			if parent.style == "ordered" && parent.itemCount > 0 {
+				newList.Offset = parent.itemCount
+			}
+			r.listCtx.current = newList
+		} else {
+			// Top-level list is done since all stack are popped: build RichTextBlock if non-empty
+			if len(r.listCtx.result) > 0 {
+				elements := make([]interface{}, len(r.listCtx.result))
+				for i, l := range r.listCtx.result {
+					elements[i] = l
+				}
+				r.blocks = append(r.blocks, RichTextBlock{
+					Type:     "rich_text",
+					Elements: elements,
+				})
+			}
+			r.listCtx = nil
+		}
+	}
+
+	return ast.WalkContinue, nil
+}
+
+// --- ListItem ---
+
+func (r *Renderer) renderListItem(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.listCtx.currentItemInlines = nil
+	} else {
+		// Only add if there are inlines (might be empty after nested list consumed them)
+		if len(r.listCtx.currentItemInlines) > 0 {
+			sec := RichTextBlock{
+				Type:     "rich_text_section",
+				Elements: r.listCtx.currentItemInlines,
+			}
+			if r.listCtx.current != nil {
+				r.listCtx.current.Elements = append(r.listCtx.current.Elements, sec)
+			}
+			r.listCtx.currentItemInlines = nil
+			// Increment parent frame's itemCount
+			if len(r.listCtx.stack) > 0 {
+				r.listCtx.stack[len(r.listCtx.stack)-1].itemCount++
+			}
+		}
+	}
+
+	return ast.WalkContinue, nil
+}
+
+// --- Table ---
+// when table is encountered, we flush the markdown and create a table context.
+// when header row is encountered, we set the isHeader flag to true
+// when each row ends in renderTableRow we add that row to rows array of table context.
+// when table cell is encountered, we apply header related styles to the collected inline items,
+// all inline items are parsed as separate AST items like list item, links, text, etc. are collected
+// using the addInline function and wrapped in a rich_text_section block.
+
+func (r *Renderer) renderTable(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.flushMrkdwn()
+		r.tableCtx = &tableContext{}
+	} else {
+		// Pad short rows to match header column count for valid Block Kit payload
+		// without this slack blockkit attachment is invalid and the API fails
+		rows := r.tableCtx.rows
+		if len(rows) > 0 {
+			maxCols := len(rows[0])
+			for i, row := range rows {
+				for len(row) < maxCols {
+					emptySec := RichTextBlock{
+						Type:     "rich_text_section",
+						Elements: []interface{}{RichTextInline{Type: "text", Text: " "}},
+					}
+					row = append(row, TableCell{
+						Type:     "rich_text",
+						Elements: []interface{}{emptySec},
+					})
+				}
+				rows[i] = row
+			}
+		}
+		r.blocks = append(r.blocks, TableBlock{
+			Type: "table",
+			Rows: rows,
+		})
+		r.tableCtx = nil
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderTableHeader(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.tableCtx.isHeader = true
+		r.tableCtx.currentRow = nil
+	} else {
+		r.tableCtx.rows = append(r.tableCtx.rows, r.tableCtx.currentRow)
+		r.tableCtx.currentRow = nil
+		r.tableCtx.isHeader = false
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderTableRow(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.tableCtx.currentRow = nil
+	} else {
+		r.tableCtx.rows = append(r.tableCtx.rows, r.tableCtx.currentRow)
+		r.tableCtx.currentRow = nil
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderTableCell(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.tableCtx.currentCellInlines = nil
+	} else {
+		// If header, make text bold for the collected inline items.
+		if r.tableCtx.isHeader {
+			for i, el := range r.tableCtx.currentCellInlines {
+				if inline, ok := el.(RichTextInline); ok {
+					if inline.Style == nil {
+						inline.Style = &RichTextStyle{Bold: true}
+					} else {
+						inline.Style.Bold = true
+					}
+					r.tableCtx.currentCellInlines[i] = inline
+				}
+			}
+		}
+		// Ensure cell has at least one element for valid Block Kit payload
+		if len(r.tableCtx.currentCellInlines) == 0 {
+			r.tableCtx.currentCellInlines = []interface{}{
+				RichTextInline{Type: "text", Text: " "},
+			}
+		}
+		// All inline items that are collected for a table cell are wrapped in a rich_text_section block.
+		sec := RichTextBlock{
+			Type:     "rich_text_section",
+			Elements: r.tableCtx.currentCellInlines,
+		}
+		// The rich_text_section block is wrapped in a rich_text block.
+		cell := TableCell{
+			Type:     "rich_text",
+			Elements: []interface{}{sec},
+		}
+		r.tableCtx.currentRow = append(r.tableCtx.currentRow, cell)
+		r.tableCtx.currentCellInlines = nil
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- TaskCheckBox ---
+
+func (r *Renderer) renderTaskCheckBox(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	n := node.(*extensionast.TaskCheckBox)
+	text := "[ ] "
+	if n.IsChecked {
+		text = "[x] "
+	}
+	if r.inRichTextMode() {
+		r.addInline(RichTextInline{Type: "text", Text: text})
+	} else {
+		r.mrkdwn.WriteString(text)
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- Inline: Text ---
+
+func (r *Renderer) renderText(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	n := node.(*ast.Text)
+	value := string(n.Segment.Value(source))
+
+	if r.inRichTextMode() {
+		r.addInline(RichTextInline{
+			Type:  "text",
+			Text:  value,
+			Style: r.currentStyle(),
+		})
+		if n.HardLineBreak() || n.SoftLineBreak() {
+			r.addInline(RichTextInline{Type: "text", Text: "\n"})
+		}
+	} else {
+		r.mrkdwn.WriteString(value)
+		if n.HardLineBreak() || n.SoftLineBreak() {
+			r.mrkdwn.WriteString("\n")
+			if r.blockquoteDepth > 0 {
+				r.mrkdwn.WriteString(strings.Repeat("> ", r.blockquoteDepth))
+			}
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- Inline: Emphasis ---
+
+func (r *Renderer) renderEmphasis(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	n := node.(*ast.Emphasis)
+	if r.inRichTextMode() {
+		if entering {
+			s := RichTextStyle{}
+			if n.Level == 1 {
+				s.Italic = true
+			} else {
+				s.Bold = true
+			}
+			r.styleStack = append(r.styleStack, s)
+		} else {
+			// the collected style gets used by the rich text element using currentStyle()
+			// so we remove this style from the stack.
+			if len(r.styleStack) > 0 {
+				r.styleStack = r.styleStack[:len(r.styleStack)-1]
+			}
+		}
+	} else {
+		if n.Level == 1 {
+			r.mrkdwn.WriteString("_")
+		} else {
+			r.mrkdwn.WriteString("*")
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- Inline: Strikethrough ---
+
+func (r *Renderer) renderStrikethrough(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if r.inRichTextMode() {
+		if entering {
+			r.styleStack = append(r.styleStack, RichTextStyle{Strike: true})
+		} else {
+			// the collected style gets used by the rich text element using currentStyle()
+			// so we remove this style from the stack.
+			if len(r.styleStack) > 0 {
+				r.styleStack = r.styleStack[:len(r.styleStack)-1]
+			}
+		}
+	} else {
+		r.mrkdwn.WriteString("~")
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- Inline: CodeSpan ---
+
+func (r *Renderer) renderCodeSpan(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	if r.inRichTextMode() {
+		// Collect all child text
+		var buf bytes.Buffer
+		for c := node.FirstChild(); c != nil; c = c.NextSibling() {
+			if t, ok := c.(*ast.Text); ok {
+				v := t.Segment.Value(source)
+				if bytes.HasSuffix(v, []byte("\n")) {
+					buf.Write(v[:len(v)-1])
+					buf.WriteByte(' ')
+				} else {
+					buf.Write(v)
+				}
+			} else if s, ok := c.(*ast.String); ok {
+				buf.Write(s.Value)
+			}
+		}
+		style := r.currentStyle()
+		if style == nil {
+			style = &RichTextStyle{Code: true}
+		} else {
+			style.Code = true
+		}
+		r.addInline(RichTextInline{
+			Type:  "text",
+			Text:  buf.String(),
+			Style: style,
+		})
+		return ast.WalkSkipChildren, nil
+	}
+	// mrkdwn mode
+	r.mrkdwn.WriteByte('`')
+	for c := node.FirstChild(); c != nil; c = c.NextSibling() {
+		if t, ok := c.(*ast.Text); ok {
+			v := t.Segment.Value(source)
+			if bytes.HasSuffix(v, []byte("\n")) {
+				r.mrkdwn.Write(v[:len(v)-1])
+				r.mrkdwn.WriteByte(' ')
+			} else {
+				r.mrkdwn.Write(v)
+			}
+		} else if s, ok := c.(*ast.String); ok {
+			r.mrkdwn.Write(s.Value)
+		}
+	}
+	r.mrkdwn.WriteByte('`')
+	return ast.WalkSkipChildren, nil
+}
+
+// --- Inline: Link ---
+
+func (r *Renderer) renderLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	n := node.(*ast.Link)
+	if r.inRichTextMode() {
+		if entering {
+			// Walk the entire subtree to collect text from all descendants,
+			// including nested inline nodes like emphasis, strong, code spans, etc.
+			var buf bytes.Buffer
+			_ = ast.Walk(node, func(child ast.Node, entering bool) (ast.WalkStatus, error) {
+				if !entering || child == node {
+					return ast.WalkContinue, nil
+				}
+				if t, ok := child.(*ast.Text); ok {
+					buf.Write(t.Segment.Value(source))
+				} else if s, ok := child.(*ast.String); ok {
+					buf.Write(s.Value)
+				}
+				return ast.WalkContinue, nil
+			})
+			// Once we've collected the text for the link (given it was present)
+			// let's add the link to the rich text block.
+			r.addInline(RichTextLink{
+				Type:  "link",
+				URL:   string(n.Destination),
+				Text:  buf.String(),
+				Style: r.currentStyle(),
+			})
+			return ast.WalkSkipChildren, nil
+		}
+	} else {
+		if entering {
+			r.mrkdwn.WriteString("<")
+			r.mrkdwn.Write(n.Destination)
+			r.mrkdwn.WriteString("|")
+		} else {
+			r.mrkdwn.WriteString(">")
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+// --- Image (skip) ---
+
+func (r *Renderer) renderImage(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	return ast.WalkSkipChildren, nil
+}

pkg/templating/slackblockkitrenderer/types.go

@@ -0,0 +1,80 @@
+package slackblockkitrenderer
+
+// SectionBlock represents a Slack section block with mrkdwn text.
+type SectionBlock struct {
+	Type string      `json:"type"`
+	Text *TextObject `json:"text"`
+}
+
+// DividerBlock represents a Slack divider block.
+type DividerBlock struct {
+	Type string `json:"type"`
+}
+
+// RichTextBlock is a container for rich text elements (lists, code blocks, table and cell blocks).
+type RichTextBlock struct {
+	Type     string        `json:"type"`
+	Elements []interface{} `json:"elements"`
+}
+
+// TableBlock represents a Slack table rendered as a rich_text block with preformatted text.
+type TableBlock struct {
+	Type string        `json:"type"`
+	Rows [][]TableCell `json:"rows"`
+}
+
+// TableCell is a cell in a table block.
+type TableCell struct {
+	Type     string        `json:"type"`
+	Elements []interface{} `json:"elements"`
+}
+
+// TextObject is the text field inside a SectionBlock.
+type TextObject struct {
+	Type string `json:"type"`
+	Text string `json:"text"`
+}
+
+// RichTextList represents an ordered or unordered list.
+type RichTextList struct {
+	Type     string        `json:"type"`
+	Style    string        `json:"style"`
+	Indent   int           `json:"indent"`
+	Border   int           `json:"border"`
+	Offset   int           `json:"offset,omitempty"`
+	Elements []interface{} `json:"elements"`
+}
+
+// RichTextPreformatted represents a code block.
+type RichTextPreformatted struct {
+	Type     string        `json:"type"`
+	Elements []interface{} `json:"elements"`
+	Border   int           `json:"border"`
+	Language string        `json:"language,omitempty"`
+}
+
+// RichTextInline represents inline text with optional styling
+// ex: text inside list, table cell
+type RichTextInline struct {
+	Type  string         `json:"type"`
+	Text  string         `json:"text"`
+	Style *RichTextStyle `json:"style,omitempty"`
+}
+
+// RichTextLink represents a link inside rich text
+// ex: link inside list, table cell
+type RichTextLink struct {
+	Type  string         `json:"type"`
+	URL   string         `json:"url"`
+	Text  string         `json:"text,omitempty"`
+	Style *RichTextStyle `json:"style,omitempty"`
+}
+
+// RichTextStyle holds boolean style flags for inline elements
+// these bools can toggle different styles for a rich text element at once.
+type RichTextStyle struct {
+	Bold   bool `json:"bold,omitempty"`
+	Italic bool `json:"italic,omitempty"`
+	Strike bool `json:"strike,omitempty"`
+	Code   bool `json:"code,omitempty"`
+}

pkg/templating/slackmrkdwnrenderer/extender.go

@@ -0,0 +1,22 @@
+package slackmrkdwnrenderer
+
+import (
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/extension"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/util"
+)
+
+type slackMrkdwn struct{}
+
+// SlackMrkdwn is a goldmark.Extender that configures the Slack mrkdwn renderer.
+var SlackMrkdwn = &slackMrkdwn{}
+
+// Extend implements goldmark.Extender.
+func (e *slackMrkdwn) Extend(m goldmark.Markdown) {
+	extension.Table.Extend(m)
+	extension.Strikethrough.Extend(m)
+	m.Renderer().AddOptions(
+		renderer.WithNodeRenderers(util.Prioritized(NewRenderer(), 1)),
+	)
+}

pkg/templating/slackmrkdwnrenderer/slack.go

@@ -0,0 +1,383 @@
+package slackmrkdwnrenderer
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/yuin/goldmark/ast"
+	extensionast "github.com/yuin/goldmark/extension/ast"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/util"
+)
+
+// Renderer renders nodes as Slack mrkdwn.
+type Renderer struct {
+	prefixes []string
+}
+
+// NewRenderer returns a new Renderer with given options.
+func NewRenderer() renderer.NodeRenderer {
+	return &Renderer{}
+}
+
+// RegisterFuncs implements NodeRenderer.RegisterFuncs.
+func (r *Renderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+	// Blocks
+	reg.Register(ast.KindDocument, r.renderDocument)
+	reg.Register(ast.KindHeading, r.renderHeading)
+	reg.Register(ast.KindBlockquote, r.renderBlockquote)
+	reg.Register(ast.KindCodeBlock, r.renderCodeBlock)
+	reg.Register(ast.KindFencedCodeBlock, r.renderCodeBlock)
+	reg.Register(ast.KindList, r.renderList)
+	reg.Register(ast.KindListItem, r.renderListItem)
+	reg.Register(ast.KindParagraph, r.renderParagraph)
+	reg.Register(ast.KindTextBlock, r.renderTextBlock)
+	reg.Register(ast.KindRawHTML, r.renderRawHTML)
+	reg.Register(ast.KindThematicBreak, r.renderThematicBreak)
+
+	// Inlines
+	reg.Register(ast.KindAutoLink, r.renderAutoLink)
+	reg.Register(ast.KindCodeSpan, r.renderCodeSpan)
+	reg.Register(ast.KindEmphasis, r.renderEmphasis)
+	reg.Register(ast.KindImage, r.renderImage)
+	reg.Register(ast.KindLink, r.renderLink)
+	reg.Register(ast.KindText, r.renderText)
+
+	// Extensions
+	reg.Register(extensionast.KindStrikethrough, r.renderStrikethrough)
+	reg.Register(extensionast.KindTable, r.renderTable)
+}
+
+func (r *Renderer) writePrefix(w util.BufWriter) {
+	for _, p := range r.prefixes {
+		_, _ = w.WriteString(p)
+	}
+}
+
+// writeLineSeparator writes a newline followed by the current prefix.
+// Used for tight separations (e.g., between list items or text blocks).
+func (r *Renderer) writeLineSeparator(w util.BufWriter) {
+	_ = w.WriteByte('\n')
+	r.writePrefix(w)
+}
+
+// writeBlockSeparator writes a blank line separator between block-level elements,
+// respecting any active prefixes for proper nesting (e.g., inside blockquotes).
+func (r *Renderer) writeBlockSeparator(w util.BufWriter) {
+	r.writeLineSeparator(w)
+	r.writeLineSeparator(w)
+}
+
+// separateFromPrevious writes a block separator if the node has a previous sibling.
+func (r *Renderer) separateFromPrevious(w util.BufWriter, n ast.Node) {
+	if n.PreviousSibling() != nil {
+		r.writeBlockSeparator(w)
+	}
+}
+
+func (r *Renderer) renderDocument(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		_, _ = w.WriteString("\n\n")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderHeading(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.separateFromPrevious(w, node)
+	}
+	_, _ = w.WriteString("*")
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderBlockquote(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.separateFromPrevious(w, n)
+		r.prefixes = append(r.prefixes, "> ")
+		_, _ = w.WriteString("> ")
+	} else {
+		r.prefixes = r.prefixes[:len(r.prefixes)-1]
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderCodeBlock(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.separateFromPrevious(w, n)
+		// start code block and write code line by line
+		_, _ = w.WriteString("```\n")
+		l := n.Lines().Len()
+		for i := 0; i < l; i++ {
+			line := n.Lines().At(i)
+			v := line.Value(source)
+			_, _ = w.Write(v)
+		}
+	} else {
+		_, _ = w.WriteString("```")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderList(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		if node.PreviousSibling() != nil {
+			r.writeLineSeparator(w)
+			// another line break if not a nested list item and starting another block
+			if node.Parent() == nil || node.Parent().Kind() != ast.KindListItem {
+				r.writeLineSeparator(w)
+			}
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderListItem(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		if n.PreviousSibling() != nil {
+			r.writeLineSeparator(w)
+		}
+		parent := n.Parent().(*ast.List)
+		// compute and write the prefix based on list type and index
+		var prefixStr string
+		if parent.IsOrdered() {
+			index := parent.Start
+			for c := parent.FirstChild(); c != nil && c != n; c = c.NextSibling() {
+				index++
+			}
+			prefixStr = fmt.Sprintf("%d. ", index)
+		} else {
+			prefixStr = "• "
+		}
+		_, _ = w.WriteString(prefixStr)
+		r.prefixes = append(r.prefixes, "\t") // add tab for nested list items
+	} else {
+		r.prefixes = r.prefixes[:len(r.prefixes)-1]
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderParagraph(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.separateFromPrevious(w, n)
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderTextBlock(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering && n.PreviousSibling() != nil {
+		r.writeLineSeparator(w)
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderRawHTML(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		n := n.(*ast.RawHTML)
+		l := n.Segments.Len()
+		for i := 0; i < l; i++ {
+			segment := n.Segments.At(i)
+			_, _ = w.Write(segment.Value(source))
+		}
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderThematicBreak(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		r.separateFromPrevious(w, n)
+		_, _ = w.WriteString("---")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderAutoLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	n := node.(*ast.AutoLink)
+	url := string(n.URL(source))
+	label := string(n.Label(source))
+
+	if n.AutoLinkType == ast.AutoLinkEmail && !strings.HasPrefix(strings.ToLower(url), "mailto:") {
+		url = "mailto:" + url
+	}
+
+	if url == label {
+		_, _ = fmt.Fprintf(w, "<%s>", url)
+	} else {
+		_, _ = fmt.Fprintf(w, "<%s|%s>", url, label)
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderCodeSpan(w util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
+	if entering {
+		_ = w.WriteByte('`')
+		for c := n.FirstChild(); c != nil; c = c.NextSibling() {
+			segment := c.(*ast.Text).Segment
+			value := segment.Value(source)
+			if bytes.HasSuffix(value, []byte("\n")) { // replace newline with space
+				_, _ = w.Write(value[:len(value)-1])
+				_ = w.WriteByte(' ')
+			} else {
+				_, _ = w.Write(value)
+			}
+		}
+		return ast.WalkSkipChildren, nil
+	}
+	_ = w.WriteByte('`')
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderEmphasis(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	n := node.(*ast.Emphasis)
+	mark := "_"
+	if n.Level == 2 {
+		mark = "*"
+	}
+	_, _ = w.WriteString(mark)
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	n := node.(*ast.Link)
+	if entering {
+		_, _ = w.WriteString("<")
+		_, _ = w.Write(util.URLEscape(n.Destination, true))
+		_, _ = w.WriteString("|")
+	} else {
+		_, _ = w.WriteString(">")
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderImage(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	n := node.(*ast.Image)
+	_, _ = w.WriteString("<")
+	_, _ = w.Write(util.URLEscape(n.Destination, true))
+	_, _ = w.WriteString("|")
+
+	// Write the alt text directly
+	var altBuf bytes.Buffer
+	for c := n.FirstChild(); c != nil; c = c.NextSibling() {
+		if textNode, ok := c.(*ast.Text); ok {
+			altBuf.Write(textNode.Segment.Value(source))
+		}
+	}
+	_, _ = w.Write(altBuf.Bytes())
+
+	_, _ = w.WriteString(">")
+	return ast.WalkSkipChildren, nil
+}
+
+func (r *Renderer) renderText(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+	n := node.(*ast.Text)
+	segment := n.Segment
+	value := segment.Value(source)
+	_, _ = w.Write(value)
+	if n.HardLineBreak() || n.SoftLineBreak() {
+		r.writeLineSeparator(w)
+	}
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderStrikethrough(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	_, _ = w.WriteString("~")
+	return ast.WalkContinue, nil
+}
+
+func (r *Renderer) renderTable(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+
+	r.separateFromPrevious(w, node)
+
+	// Collect cells and max widths
+	var rows [][]string
+	var colWidths []int
+
+	for c := node.FirstChild(); c != nil; c = c.NextSibling() {
+		if c.Kind() == extensionast.KindTableHeader || c.Kind() == extensionast.KindTableRow {
+			var row []string
+			colIdx := 0
+			for cc := c.FirstChild(); cc != nil; cc = cc.NextSibling() {
+				if cc.Kind() == extensionast.KindTableCell {
+					cellText := extractPlainText(cc, source)
+					row = append(row, cellText)
+					runeLen := utf8.RuneCountInString(cellText)
+					if colIdx >= len(colWidths) {
+						colWidths = append(colWidths, runeLen)
+					} else if runeLen > colWidths[colIdx] {
+						colWidths[colIdx] = runeLen
+					}
+					colIdx++
+				}
+			}
+			rows = append(rows, row)
+		}
+	}
+
+	// writing table in code block
+	_, _ = w.WriteString("```\n")
+	for i, row := range rows {
+		for colIdx, cellText := range row {
+			width := 0
+			if colIdx < len(colWidths) {
+				width = colWidths[colIdx]
+			}
+			runeLen := utf8.RuneCountInString(cellText)
+			padding := max(0, width-runeLen)
+
+			_, _ = w.WriteString(cellText)
+			_, _ = w.WriteString(strings.Repeat(" ", padding))
+			if colIdx < len(row)-1 {
+				_, _ = w.WriteString(" | ")
+			}
+		}
+		_ = w.WriteByte('\n')
+
+		// Print separator after header
+		if i == 0 {
+			for colIdx := range row {
+				width := 0
+				if colIdx < len(colWidths) {
+					width = colWidths[colIdx]
+				}
+				_, _ = w.WriteString(strings.Repeat("-", width))
+				if colIdx < len(row)-1 {
+					_, _ = w.WriteString("-|-")
+				}
+			}
+			_ = w.WriteByte('\n')
+		}
+	}
+	_, _ = w.WriteString("```")
+
+	return ast.WalkSkipChildren, nil
+}
+
+// extractPlainText extracts all the text content from the given node.
+func extractPlainText(n ast.Node, source []byte) string {
+	var buf bytes.Buffer
+	_ = ast.Walk(n, func(node ast.Node, entering bool) (ast.WalkStatus, error) {
+		if !entering {
+			return ast.WalkContinue, nil
+		}
+		if textNode, ok := node.(*ast.Text); ok {
+			buf.Write(textNode.Segment.Value(source))
+		} else if strNode, ok := node.(*ast.String); ok {
+			buf.Write(strNode.Value)
+		}
+		return ast.WalkContinue, nil
+	})
+	return strings.TrimSpace(buf.String())
+}

pkg/templating/slackmrkdwnrenderer/slack_test.go

@@ -0,0 +1,115 @@
+package slackmrkdwnrenderer
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/yuin/goldmark"
+)
+
+func TestRenderer(t *testing.T) {
+	tests := []struct {
+		name     string
+		markdown string
+		expected string
+	}{
+		{
+			name:     "Heading with Thematic Break",
+			markdown: "# Title 1\n# Hello World\n---\nthis is sometext",
+			expected: "*Title 1*\n\n*Hello World*\n\n---\n\nthis is sometext\n\n",
+		},
+		{
+			name:     "Blockquote",
+			markdown: "> This is a quote\n> It continues",
+			expected: "> This is a quote\n> It continues\n\n",
+		},
+		{
+			name:     "Fenced Code Block",
+			markdown: "```go\npackage main\nfunc main() {}\n```",
+			expected: "```\npackage main\nfunc main() {}\n```\n\n",
+		},
+		{
+			name:     "Unordered List",
+			markdown: "- item 1\n- item 2\n- item 3",
+			expected: "• item 1\n• item 2\n• item 3\n\n",
+		},
+		{
+			name:     "nested unordered list",
+			markdown: "- item 1\n- item 2\n\t- item 2.1\n\t\t- item 2.1.1\n\t\t- item 2.1.2\n\t- item 2.2\n- item 3",
+			expected: "• item 1\n• item 2\n\t• item 2.1\n\t\t• item 2.1.1\n\t\t• item 2.1.2\n\t• item 2.2\n• item 3\n\n",
+		},
+		{
+			name:     "Ordered List",
+			markdown: "1. item 1\n2. item 2\n3. item 3",
+			expected: "1. item 1\n2. item 2\n3. item 3\n\n",
+		},
+		{
+			name:     "nested ordered list",
+			markdown: "1. item 1\n2. item 2\n\t1. item 2.1\n\t\t1. item 2.1.1\n\t\t2. item 2.1.2\n\t2. item 2.2\n\t3. item 2.3\n3. item 3\n4. item 4",
+			expected: "1. item 1\n2. item 2\n\t1. item 2.1\n\t\t1. item 2.1.1\n\t\t2. item 2.1.2\n\t2. item 2.2\n\t3. item 2.3\n3. item 3\n4. item 4\n\n",
+		},
+		{
+			name:     "Links and AutoLinks",
+			markdown: "This is a [link](https://example.com) and an autolink <https://test.com>",
+			expected: "This is a <https://example.com|link> and an autolink <https://test.com>\n\n",
+		},
+		{
+			name:     "Images",
+			markdown: "An image ![alt text](https://example.com/image.png)",
+			expected: "An image <https://example.com/image.png|alt text>\n\n",
+		},
+		{
+			name:     "Emphasis",
+			markdown: "This is **bold** and *italic* and __bold__ and _italic_",
+			expected: "This is *bold* and _italic_ and *bold* and _italic_\n\n",
+		},
+		{
+			name:     "Strikethrough",
+			markdown: "This is ~~strike~~",
+			expected: "This is ~strike~\n\n",
+		},
+		{
+			name:     "Code Span",
+			markdown: "This is `inline code` embedded.",
+			expected: "This is `inline code` embedded.\n\n",
+		},
+		{
+			name:     "Table",
+			markdown: "Col 1 | Col 2 | Col 3\n--- | --- | ---\nVal 1 | Long Value 2 | 3\nShort | V | 1000",
+			expected: "```\nCol 1 | Col 2        | Col 3\n------|--------------|------\nVal 1 | Long Value 2 | 3    \nShort | V            | 1000 \n```\n\n",
+		},
+		{
+			name:     "Mixed Nested Lists",
+			markdown: "1. first\n\t- nested bullet\n\t- another bullet\n2. second",
+			expected: "1. first\n\t• nested bullet\n\t• another bullet\n2. second\n\n",
+		},
+		{
+			name:     "Email AutoLink",
+			markdown: "<user@example.com>",
+			expected: "<mailto:user@example.com|user@example.com>\n\n",
+		},
+		{
+			name:     "No value string parsed as is",
+			markdown: "Service: <no value>",
+			expected: "Service: <no value>\n\n",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			md := goldmark.New(goldmark.WithExtensions(SlackMrkdwn))
+
+			var buf bytes.Buffer
+			if err := md.Convert([]byte(tt.markdown), &buf); err != nil {
+				t.Fatalf("failed to convert: %v", err)
+			}
+
+			// Do exact string matching
+			actual := buf.String()
+			if actual != tt.expected {
+				t.Errorf("\nExpected:\n%q\nGot:\n%q\nRaw Expected:\n%s\nRaw Got:\n%s",
+					tt.expected, actual, tt.expected, actual)
+			}
+		})
+	}
+}

pkg/templating/templatingextensions/html.go

@@ -0,0 +1,66 @@
+package templatingextensions
+
+import (
+	"github.com/yuin/goldmark"
+	gast "github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/renderer"
+	"github.com/yuin/goldmark/renderer/html"
+	"github.com/yuin/goldmark/util"
+)
+
+// NoValueHTMLRenderer is a renderer.NodeRenderer implementation that
+// renders <no value> as escaped visible text instead of omitting it.
+type NoValueHTMLRenderer struct {
+	html.Config
+}
+
+// NewNoValueHTMLRenderer returns a new NoValueHTMLRenderer.
+func NewNoValueHTMLRenderer(opts ...html.Option) renderer.NodeRenderer {
+	r := &NoValueHTMLRenderer{
+		Config: html.NewConfig(),
+	}
+	for _, opt := range opts {
+		opt.SetHTMLOption(&r.Config)
+	}
+	return r
+}
+
+// RegisterFuncs implements renderer.NodeRenderer.RegisterFuncs.
+func (r *NoValueHTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
+	reg.Register(gast.KindRawHTML, r.renderRawHTML)
+}
+
+func (r *NoValueHTMLRenderer) renderRawHTML(
+	w util.BufWriter, source []byte, node gast.Node, entering bool) (gast.WalkStatus, error) {
+	if !entering {
+		return gast.WalkSkipChildren, nil
+	}
+	if r.Unsafe {
+		n := node.(*gast.RawHTML)
+		for i := 0; i < n.Segments.Len(); i++ {
+			segment := n.Segments.At(i)
+			_, _ = w.Write(segment.Value(source))
+		}
+		return gast.WalkSkipChildren, nil
+	}
+	n := node.(*gast.RawHTML)
+	raw := string(n.Segments.Value(source))
+	if raw == "<no value>" {
+		_, _ = w.WriteString("&lt;no value&gt;")
+		return gast.WalkSkipChildren, nil
+	}
+	_, _ = w.WriteString("<!-- raw HTML omitted -->")
+	return gast.WalkSkipChildren, nil
+}
+
+type escapeNoValue struct{}
+
+// EscapeNoValue is an extension that renders <no value> as visible
+// escaped text instead of omitting it as raw HTML.
+var EscapeNoValue = &escapeNoValue{}
+
+func (e *escapeNoValue) Extend(m goldmark.Markdown) {
+	m.Renderer().AddOptions(renderer.WithNodeRenderers(
+		util.Prioritized(NewNoValueHTMLRenderer(), 500),
+	))
+}

pkg/templating/templatingextensions/html_test.go

@@ -0,0 +1,66 @@
+package templatingextensions
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/extension"
+)
+
+func TestEscapeNoValue(t *testing.T) {
+	tests := []struct {
+		name     string
+		markdown string
+		expected string
+	}{
+		{
+			name:     "plain text",
+			markdown: "Service: <no value>",
+			expected: "<p>Service: &lt;no value&gt;</p>\n",
+		},
+		{
+			name:     "inside strong",
+			markdown: "Service: **<no value>**",
+			expected: "<p>Service: <strong>&lt;no value&gt;</strong></p>\n",
+		},
+		{
+			name:     "inside emphasis",
+			markdown: "Service: *<no value>*",
+			expected: "<p>Service: <em>&lt;no value&gt;</em></p>\n",
+		},
+		{
+			name:     "inside strikethrough",
+			markdown: "Service: ~~<no value>~~",
+			expected: "<p>Service: <del>&lt;no value&gt;</del></p>\n",
+		},
+		{
+			name:     "real html still omitted",
+			markdown: "hello <div>world</div>",
+			expected: "<p>hello <!-- raw HTML omitted -->world<!-- raw HTML omitted --></p>\n",
+		},
+		{
+			name:     "inside heading",
+			markdown: "# Title <no value>",
+			expected: "<h1>Title &lt;no value&gt;</h1>\n",
+		},
+		{
+			name:     "inside list item",
+			markdown: "- item <no value>",
+			expected: "<ul>\n<li>item &lt;no value&gt;</li>\n</ul>\n",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gm := goldmark.New(goldmark.WithExtensions(EscapeNoValue, extension.Strikethrough))
+			var buf bytes.Buffer
+			if err := gm.Convert([]byte(tt.markdown), &buf); err != nil {
+				t.Fatal(err)
+			}
+			if buf.String() != tt.expected {
+				t.Errorf("expected:\n%s\ngot:\n%s", tt.expected, buf.String())
+			}
+		})
+	}
+}