diff --git a/pkg/agent/agent_test.go b/pkg/agent/agent_test.go
index b0aa3b468..030b65a6d 100644
--- a/pkg/agent/agent_test.go
+++ b/pkg/agent/agent_test.go
@@ -1965,6 +1965,17 @@ func TestToolFeedbackExplanationFromResponse_DoesNotUseReasoningContent(t *testi
 	}
 }
 
+func TestToolFeedbackArgsPreview_UsesJSONAndTruncates(t *testing.T) {
+	got := toolFeedbackArgsPreview(map[string]any{
+		"path":  "README.md",
+		"limit": 42,
+	}, 128)
+	want := "{\n  \"limit\": 42,\n  \"path\": \"README.md\"\n}"
+	if got != want {
+		t.Fatalf("toolFeedbackArgsPreview() = %q, want %q", got, want)
+	}
+}
+
 type picoInterleavedContentProvider struct {
 	calls int
 }
@@ -3940,6 +3951,12 @@ func TestProcessMessage_PublishesToolFeedbackWhenEnabled(t *testing.T) {
 		if !strings.Contains(outbound.Content, "check tool feedback") {
 			t.Fatalf("tool feedback content = %q, want current user intent fallback", outbound.Content)
 		}
+		if !strings.Contains(outbound.Content, "\"path\":") {
+			t.Fatalf("tool feedback content = %q, want serialized tool arguments", outbound.Content)
+		}
+		if !strings.Contains(outbound.Content, heartbeatFile) {
+			t.Fatalf("tool feedback content = %q, want tool argument value", outbound.Content)
+		}
 		if strings.Contains(outbound.Content, "Previous turn explanation") {
 			t.Fatalf("tool feedback content = %q, want no previous assistant fallback", outbound.Content)
 		}
@@ -4012,6 +4029,12 @@ func TestProcessMessage_DoesNotLeakReasoningContentInToolFeedback(t *testing.T)
 		if !strings.Contains(outbound.Content, "check reasoning fallback") {
 			t.Fatalf("tool feedback content = %q, want current user intent fallback", outbound.Content)
 		}
+		if !strings.Contains(outbound.Content, "\"path\":") {
+			t.Fatalf("tool feedback content = %q, want serialized tool arguments", outbound.Content)
+		}
+		if !strings.Contains(outbound.Content, heartbeatFile) {
+			t.Fatalf("tool feedback content = %q, want tool argument value", outbound.Content)
+		}
 		if strings.Contains(outbound.Content, "Read README.md first") {
 			t.Fatalf("tool feedback content = %q, should not leak hidden reasoning", outbound.Content)
 		}
@@ -4310,7 +4333,7 @@ func TestRun_PicoToolFeedbackSuppressesDuplicateInterimAssistantContent(t *testi
 		}
 	}
 
-	if outputs[0] != "🔧 `tool_limit_test_tool`\nintermediate model text" {
+	if outputs[0] != "🔧 `tool_limit_test_tool`\nintermediate model text\n```json\n{\n  \"value\": \"x\"\n}\n```" {
 		t.Fatalf("first outbound content = %q, want tool feedback summary", outputs[0])
 	}
 	if outputs[1] != "final model text" {
diff --git a/pkg/agent/agent_utils.go b/pkg/agent/agent_utils.go
index ff98dad68..17fb9dd1f 100644
--- a/pkg/agent/agent_utils.go
+++ b/pkg/agent/agent_utils.go
@@ -4,6 +4,7 @@ package agent
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"path/filepath"
 	"strings"
@@ -170,6 +171,18 @@ func toolFeedbackExplanationFromMessages(messages []providers.Message) string {
 	return ""
 }
 
+func toolFeedbackArgsPreview(args map[string]any, maxLen int) string {
+	if args == nil {
+		args = map[string]any{}
+	}
+
+	argsJSON, err := json.MarshalIndent(args, "", "  ")
+	if err != nil {
+		return utils.Truncate(fmt.Sprintf("%v", args), maxLen)
+	}
+	return utils.Truncate(string(argsJSON), maxLen)
+}
+
 func shouldPublishToolFeedback(cfg *config.Config, ts *turnState) bool {
 	if ts == nil || ts.channel == "" || ts.opts.SuppressToolFeedback {
 		return false
diff --git a/pkg/agent/pipeline_execute.go b/pkg/agent/pipeline_execute.go
index 0e67e4faf..0cf3eaa9a 100644
--- a/pkg/agent/pipeline_execute.go
+++ b/pkg/agent/pipeline_execute.go
@@ -81,13 +81,18 @@ toolLoop:
 					)
 
 					if shouldPublishToolFeedback(al.cfg, ts) {
+						toolFeedbackMaxLen := al.cfg.Agents.Defaults.GetToolFeedbackMaxArgsLength()
 						toolFeedbackExplanation := toolFeedbackExplanationForToolCall(
 							exec.response,
 							tc,
 							messages,
-							al.cfg.Agents.Defaults.GetToolFeedbackMaxArgsLength(),
+							toolFeedbackMaxLen,
+						)
+						feedbackMsg := utils.FormatToolFeedbackMessage(
+							toolName,
+							toolFeedbackExplanation,
+							toolFeedbackArgsPreview(toolArgs, toolFeedbackMaxLen),
 						)
-						feedbackMsg := utils.FormatToolFeedbackMessage(toolName, toolFeedbackExplanation)
 						fbCtx, fbCancel := context.WithTimeout(turnCtx, 3*time.Second)
 						_ = al.bus.PublishOutbound(fbCtx, outboundMessageForTurnWithKind(ts, feedbackMsg, messageKindToolFeedback))
 						fbCancel()
@@ -358,13 +363,18 @@ toolLoop:
 		)
 
 		if shouldPublishToolFeedback(al.cfg, ts) {
+			toolFeedbackMaxLen := al.cfg.Agents.Defaults.GetToolFeedbackMaxArgsLength()
 			toolFeedbackExplanation := toolFeedbackExplanationForToolCall(
 				exec.response,
 				tc,
 				messages,
-				al.cfg.Agents.Defaults.GetToolFeedbackMaxArgsLength(),
+				toolFeedbackMaxLen,
+			)
+			feedbackMsg := utils.FormatToolFeedbackMessage(
+				toolName,
+				toolFeedbackExplanation,
+				toolFeedbackArgsPreview(toolArgs, toolFeedbackMaxLen),
 			)
-			feedbackMsg := utils.FormatToolFeedbackMessage(toolName, toolFeedbackExplanation)
 			fbCtx, fbCancel := context.WithTimeout(turnCtx, 3*time.Second)
 			_ = al.bus.PublishOutbound(fbCtx, outboundMessageForTurnWithKind(ts, feedbackMsg, messageKindToolFeedback))
 			fbCancel()
diff --git a/pkg/channels/telegram/parser_markdown_to_html_test.go b/pkg/channels/telegram/parser_markdown_to_html_test.go
index a05b39877..a54a1c2c7 100644
--- a/pkg/channels/telegram/parser_markdown_to_html_test.go
+++ b/pkg/channels/telegram/parser_markdown_to_html_test.go
@@ -65,6 +65,11 @@ func Test_markdownToTelegramHTML(t *testing.T) {
 			input:    "a & b < c > d",
 			expected: "a &amp; b &lt; c &gt; d",
 		},
+		{
+			name:     "code block with language",
+			input:    "```json\n{\n  \"path\": \"README.md\"\n}\n```",
+			expected: "<pre><code>{\n  \"path\": \"README.md\"\n}\n</code></pre>",
+		},
 	}
 
 	for _, tc := range cases {
diff --git a/pkg/utils/tool_feedback.go b/pkg/utils/tool_feedback.go
index 1a8b6c747..de7cb467e 100644
--- a/pkg/utils/tool_feedback.go
+++ b/pkg/utils/tool_feedback.go
@@ -7,21 +7,31 @@ import (
 
 const ToolFeedbackContinuationHint = "Continuing the current task."
 
-// FormatToolFeedbackMessage renders the model-provided explanation for why a
-// tool is being executed. When the model does not provide one, it keeps only
-// the tool line and does not expose raw arguments or fallback text.
-func FormatToolFeedbackMessage(toolName, explanation string) string {
+// FormatToolFeedbackMessage renders a tool feedback message for chat channels.
+// It keeps the tool name on the first line for animation and can include both
+// a human explanation and the serialized tool arguments in the body.
+func FormatToolFeedbackMessage(toolName, explanation, argsPreview string) string {
 	toolName = strings.TrimSpace(toolName)
 	explanation = strings.TrimSpace(explanation)
+	argsPreview = strings.TrimSpace(argsPreview)
+
+	bodyLines := make([]string, 0, 2)
+	if explanation != "" {
+		bodyLines = append(bodyLines, explanation)
+	}
+	if argsPreview != "" {
+		bodyLines = append(bodyLines, "```json\n"+argsPreview+"\n```")
+	}
+	body := strings.Join(bodyLines, "\n")
 
 	if toolName == "" {
-		return explanation
+		return body
 	}
-	if explanation == "" {
+	if body == "" {
 		return fmt.Sprintf("\U0001f527 `%s`", toolName)
 	}
 
-	return fmt.Sprintf("\U0001f527 `%s`\n%s", toolName, explanation)
+	return fmt.Sprintf("\U0001f527 `%s`\n%s", toolName, body)
 }
 
 // FitToolFeedbackMessage keeps tool feedback within a single outbound message.
diff --git a/pkg/utils/tool_feedback_test.go b/pkg/utils/tool_feedback_test.go
index 316ce2408..c30f53827 100644
--- a/pkg/utils/tool_feedback_test.go
+++ b/pkg/utils/tool_feedback_test.go
@@ -6,29 +6,38 @@ func TestFormatToolFeedbackMessage(t *testing.T) {
 	got := FormatToolFeedbackMessage(
 		"read_file",
 		"I will read README.md first to confirm the current project structure.",
+		"{\n  \"path\": \"README.md\"\n}",
 	)
-	want := "\U0001f527 `read_file`\nI will read README.md first to confirm the current project structure."
+	want := "\U0001f527 `read_file`\nI will read README.md first to confirm the current project structure.\n```json\n{\n  \"path\": \"README.md\"\n}\n```"
 	if got != want {
 		t.Fatalf("FormatToolFeedbackMessage() = %q, want %q", got, want)
 	}
 }
 
-func TestFormatToolFeedbackMessage_EmptyExplanationKeepsOnlyToolLine(t *testing.T) {
-	got := FormatToolFeedbackMessage("read_file", "")
-	want := "\U0001f527 `read_file`"
+func TestFormatToolFeedbackMessage_EmptyExplanationShowsArgs(t *testing.T) {
+	got := FormatToolFeedbackMessage("read_file", "", "{\n  \"path\": \"README.md\"\n}")
+	want := "\U0001f527 `read_file`\n```json\n{\n  \"path\": \"README.md\"\n}\n```"
 	if got != want {
 		t.Fatalf("FormatToolFeedbackMessage() = %q, want %q", got, want)
 	}
 }
 
 func TestFormatToolFeedbackMessage_EmptyToolNameOmitsToolLine(t *testing.T) {
-	got := FormatToolFeedbackMessage("", "Continue drafting the final response.")
+	got := FormatToolFeedbackMessage("", "Continue drafting the final response.", "")
 	want := "Continue drafting the final response."
 	if got != want {
 		t.Fatalf("FormatToolFeedbackMessage() = %q, want %q", got, want)
 	}
 }
 
+func TestFormatToolFeedbackMessage_EmptyExplanationAndArgsKeepsOnlyToolLine(t *testing.T) {
+	got := FormatToolFeedbackMessage("read_file", "", "")
+	want := "\U0001f527 `read_file`"
+	if got != want {
+		t.Fatalf("FormatToolFeedbackMessage() = %q, want %q", got, want)
+	}
+}
+
 func TestFitToolFeedbackMessage_TruncatesBodyWithinSingleMessage(t *testing.T) {
 	got := FitToolFeedbackMessage(
 		"\U0001f527 `read_file`\nRead README.md first to confirm the current project structure.",
diff --git a/web/backend/api/session.go b/web/backend/api/session.go
index 6ac1eb988..85f928ec6 100644
--- a/web/backend/api/session.go
+++ b/web/backend/api/session.go
@@ -2,6 +2,7 @@ package api
 
 import (
 	"bufio"
+	"bytes"
 	"encoding/json"
 	"errors"
 	"net/http"
@@ -593,7 +594,15 @@ func toolSummaryContainsContent(summary, content string) bool {
 	}
 
 	_, body, hasBody := strings.Cut(summary, "\n")
-	return hasBody && strings.TrimSpace(body) == content
+	if !hasBody {
+		return false
+	}
+	body = strings.TrimSpace(body)
+	if body == content {
+		return true
+	}
+	firstSection, _, _ := strings.Cut(body, "\n```")
+	return strings.TrimSpace(firstSection) == content
 }
 
 func sessionAttachments(msg providers.Message) []sessionChatAttachment {
@@ -714,7 +723,8 @@ func visibleAssistantToolSummaryMessages(
 			Role: "assistant",
 			Content: utils.FormatToolFeedbackMessage(
 				name,
-				visibleAssistantToolSummaryText(tc, toolFeedbackMaxArgsLength),
+				visibleAssistantToolFeedbackExplanation(tc, toolFeedbackMaxArgsLength),
+				visibleAssistantToolArgsPreview(tc, toolFeedbackMaxArgsLength),
 			),
 		})
 	}
@@ -722,7 +732,7 @@ func visibleAssistantToolSummaryMessages(
 	return messages
 }
 
-func visibleAssistantToolSummaryText(
+func visibleAssistantToolFeedbackExplanation(
 	tc providers.ToolCall,
 	toolFeedbackMaxArgsLength int,
 ) string {
@@ -731,18 +741,32 @@ func visibleAssistantToolSummaryText(
 			return utils.Truncate(explanation, toolFeedbackMaxArgsLength)
 		}
 	}
+	return ""
+}
 
+func visibleAssistantToolArgsPreview(
+	tc providers.ToolCall,
+	toolFeedbackMaxArgsLength int,
+) string {
 	argsJSON := ""
 	if tc.Function != nil {
 		argsJSON = tc.Function.Arguments
 	}
 	if strings.TrimSpace(argsJSON) == "" && len(tc.Arguments) > 0 {
-		if encodedArgs, err := json.Marshal(tc.Arguments); err == nil {
+		if encodedArgs, err := json.MarshalIndent(tc.Arguments, "", "  "); err == nil {
 			argsJSON = string(encodedArgs)
 		}
 	}
+	argsJSON = strings.TrimSpace(argsJSON)
+	if argsJSON == "" {
+		return ""
+	}
+	var pretty bytes.Buffer
+	if err := json.Indent(&pretty, []byte(argsJSON), "", "  "); err == nil {
+		argsJSON = pretty.String()
+	}
 
-	return utils.Truncate(strings.TrimSpace(argsJSON), toolFeedbackMaxArgsLength)
+	return utils.Truncate(argsJSON, toolFeedbackMaxArgsLength)
 }
 
 func visibleAssistantToolMessages(toolCalls []providers.ToolCall) []sessionChatMessage {
diff --git a/web/backend/api/session_test.go b/web/backend/api/session_test.go
index 6afb8a94f..428c565a8 100644
--- a/web/backend/api/session_test.go
+++ b/web/backend/api/session_test.go
@@ -1056,8 +1056,11 @@ func TestHandleGetSession_UsesConfiguredToolFeedbackMaxArgsLength(t *testing.T)
 	if !strings.Contains(resp.Messages[1].Content, wantPreview) {
 		t.Fatalf("tool summary = %q, want preview %q", resp.Messages[1].Content, wantPreview)
 	}
-	if strings.Contains(resp.Messages[1].Content, argsJSON) {
-		t.Fatalf("tool summary = %q, expected configured truncation", resp.Messages[1].Content)
+	wantArgsPreview := visibleAssistantToolArgsPreview(providers.ToolCall{
+		Function: &providers.FunctionCall{Arguments: argsJSON},
+	}, 20)
+	if !strings.Contains(resp.Messages[1].Content, wantArgsPreview) {
+		t.Fatalf("tool summary = %q, want args preview %q", resp.Messages[1].Content, wantArgsPreview)
 	}
 	if !strings.Contains(resp.Messages[1].Content, "`read_file`") {
 		t.Fatalf("tool summary = %q, want read_file summary", resp.Messages[1].Content)
@@ -1132,7 +1135,9 @@ func TestHandleGetSession_FallsBackToLegacyToolArgumentsWhenExplanationMissing(t
 		t.Fatalf("len(resp.Messages) = %d, want at least 2", len(resp.Messages))
 	}
 
-	wantPreview := utils.Truncate(argsJSON, 20)
+	wantPreview := visibleAssistantToolArgsPreview(providers.ToolCall{
+		Function: &providers.FunctionCall{Arguments: argsJSON},
+	}, 20)
 	if !strings.Contains(resp.Messages[1].Content, "`read_file`") {
 		t.Fatalf("tool summary = %q, want read_file summary", resp.Messages[1].Content)
 	}