diff --git a/agent/sandbox/v2/claude/parse.go b/agent/sandbox/v2/claude/parse.go
index 473167ac..5714a368 100644
--- a/agent/sandbox/v2/claude/parse.go
+++ b/agent/sandbox/v2/claude/parse.go
@@ -326,6 +326,12 @@ func (p *streamParser) onContentBlockDelta(event map[string]any) (stopped bool)
 		if text == "" {
 			return false
 		}
+		// If there is no active text message and this delta is only
+		// whitespace, buffer it instead of opening a brand-new message
+		// group just for spaces/indentation between tool calls.
+		if !p.textActive && strings.TrimSpace(text) == "" {
+			return false
+		}
 		if p.ensureTextMessage() {
 			return true
 		}
@@ -448,6 +454,12 @@ func (p *streamParser) handleUser(msg map[string]any) (stopped bool) {
 			continue
 		}
 
+		// Close any open text message before opening an execute message,
+		// otherwise textActive stays true while currentGroupID gets
+		// overwritten by the execute message lifecycle, causing subsequent
+		// text chunks to be emitted without a message_id.
+		p.closeTextMessage()
+
 		toolUseID, _ := ci["tool_use_id"].(string)
 		content := ci["content"]
 		isError, _ := ci["is_error"].(bool)
diff --git a/agent/sandbox/v2/claude/runner.go b/agent/sandbox/v2/claude/runner.go
index 44c745b7..d08a2c12 100644
--- a/agent/sandbox/v2/claude/runner.go
+++ b/agent/sandbox/v2/claude/runner.go
@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"os"
 	"strings"
 
 	"github.com/yaoapp/gou/connector"
@@ -52,7 +51,7 @@ func (r *ClaudeRunner) Prepare(ctx context.Context, req *types.PrepareRequest) e
 			src := "local:///" + req.SkillsDir
 			dst := prefix + "/skills"
 			if _, err := ws.Copy(src, dst); err != nil {
-				fmt.Fprintf(os.Stderr, "[claude] warn: copy skills %s -> %s: %v\n", src, dst, err)
+				r.logger.Warn("copy skills %s -> %s: %v", src, dst, err)
 			}
 		}
 	}
@@ -115,6 +114,10 @@ func (r *ClaudeRunner) Stream(ctx context.Context, req *types.StreamRequest, han
 
 	completed, err := sess.runStream(handler)
 	r.lastCompleted = completed
+	r.logger.Debug("Stream: runStream returned completed=%v err=%v", completed, err)
+	if completed {
+		sess.shutdown()
+	}
 	return err
 }
 
diff --git a/agent/sandbox/v2/claude/session.go b/agent/sandbox/v2/claude/session.go
index 05333653..1f0450dc 100644
--- a/agent/sandbox/v2/claude/session.go
+++ b/agent/sandbox/v2/claude/session.go
@@ -59,6 +59,8 @@ func (s *session) runStream(handler message.StreamFunc) (completed bool, err err
 	parser := newStreamParser(handler)
 	parseErr := parser.parse(s.ctx, s.exec.Stdout)
 
+	s.logger.Debug("runStream: parse returned completed=%v parseErr=%v", parser.completed, parseErr)
+
 	if parser.completed {
 		s.logger.Info("claude stream completed normally")
 		return true, nil
@@ -127,6 +129,26 @@ func (s *session) watchCancel() func() {
 	return func() { close(done) }
 }
 
+// shutdown terminates the claude process after a normal stream completion.
+//
+// Claude CLI's stream-json mode has a known bug where the process hangs
+// indefinitely after emitting the "result" event (anthropics/claude-code#25629).
+// There is no graceful exit mechanism, so we must kill the process externally.
+//
+// We send SIGKILL (-9) to processes named exactly "claude". SIGKILL cannot be
+// caught, so Claude CLI has no opportunity to run its SIGTERM handler which
+// would actively terminate child processes (web servers, etc.). Those children
+// survive because they run in separate process groups/sessions.
+func (s *session) shutdown() {
+	s.logger.Info("shutting down completed claude exec session")
+	killCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	result, err := s.computer.Exec(killCtx, []string{"sh", "-c", "pkill -9 -x claude || true"})
+	s.logger.Debug("shutdown: pkill -9 -x claude exitCode=%d err=%v", result.ExitCode, err)
+	s.exec.Cancel()
+}
+
 // waitForExit waits for the Claude process to exit with timeout protection.
 // This fixes the old code's issue where Wait() could block forever.
 func (s *session) waitForExit(parseErr error) error {