bugfix: fix crash bug in token cache logic

This change fixes a problem in the token cache logic to avoid panics caused by empty token arrays
by ensuring at least one token remains on full cache hits in the relevant function. The happens
if there is an exact match in the cache on subsequent generations.

app/cmd/app/app.go

@@ -296,8 +296,15 @@ func main() {
 
 	// Check for pending updates on startup (show tray notification if update is ready)
 	if updater.IsUpdatePending() {
-		slog.Debug("update pending on startup, showing tray notification")
-		UpdateAvailable("")
+		// On Windows, the tray is initialized in osRun(). Calling UpdateAvailable
+		// before that would dereference a nil tray callback.
+		// TODO: refactor so the update check runs after platform init on all platforms.
+		if runtime.GOOS == "windows" {
+			slog.Debug("update pending on startup, deferring tray notification until tray initialization")
+		} else {
+			slog.Debug("update pending on startup, showing tray notification")
+			UpdateAvailable("")
+		}
 	}
 
 	hasCompletedFirstRun, err := st.HasCompletedFirstRun()

app/cmd/app/app_windows.go

@@ -154,6 +154,10 @@ func handleURLSchemeRequest(urlScheme string) {
 }
 
 func UpdateAvailable(ver string) error {
+	if app.t == nil {
+		slog.Debug("tray not yet initialized, skipping update notification")
+		return nil
+	}
 	return app.t.UpdateAvailable(ver)
 }
 
@@ -165,6 +169,14 @@ func osRun(shutdown func(), hasCompletedFirstRun, startHidden bool) {
 		log.Fatalf("Failed to start: %s", err)
 	}
 
+	// Check for pending updates now that the tray is initialized.
+	// The platform-independent check in app.go fires before osRun,
+	// when app.t is still nil, so we must re-check here.
+	if updater.IsUpdatePending() {
+		slog.Debug("update pending on startup, showing tray notification")
+		UpdateAvailable("")
+	}
+
 	signals := make(chan os.Signal, 1)
 	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM)
 

model/parsers/qwen3.go

@@ -204,6 +204,24 @@ func (p *Qwen3Parser) eat() ([]qwen3Event, bool) {
 			p.maybeThinkingOpenAtBOL = false
 		}
 
+		thinkingCloseIdx := strings.Index(acc, qwen3ThinkingCloseTag)
+		toolOpenIdx := strings.Index(acc, qwen3ToolOpenTag)
+
+		// If a tool call starts before </think>, treat that as the end of thinking
+		// for parsing purposes and continue in tool-call mode.
+		if toolOpenIdx != -1 && (thinkingCloseIdx == -1 || toolOpenIdx < thinkingCloseIdx) {
+			before, after := p.splitAtTag(qwen3ToolOpenTag, true)
+			if len(before) > 0 {
+				events = append(events, qwen3EventThinkingContent{content: before})
+			}
+			if after == "" {
+				p.state = qwen3ParserStateToolStartedEatingWhitespace
+			} else {
+				p.state = qwen3ParserStateCollectingToolContent
+			}
+			return events, true
+		}
+
 		if strings.Contains(acc, qwen3ThinkingCloseTag) {
 			thinking, remaining := p.splitAtTag(qwen3ThinkingCloseTag, true)
 			if len(thinking) > 0 {
@@ -215,7 +233,7 @@ func (p *Qwen3Parser) eat() ([]qwen3Event, bool) {
 				p.state = qwen3ParserStateCollectingContent
 			}
 			return events, true
-		} else if overlapLen := overlap(acc, qwen3ThinkingCloseTag); overlapLen > 0 {
+		} else if overlapLen := max(overlap(acc, qwen3ThinkingCloseTag), overlap(acc, qwen3ToolOpenTag)); overlapLen > 0 {
 			beforePartialTag := acc[:len(acc)-overlapLen]
 			trailingWsLen := trailingWhitespaceLen(beforePartialTag)
 			ambiguousStart := len(beforePartialTag) - trailingWsLen

model/parsers/qwen3_test.go

@@ -146,6 +146,68 @@ func TestQwen3ParserToolCall(t *testing.T) {
 	}
 }
 
+func TestQwen3ParserThinkingWithToolCallBeforeThinkingClose(t *testing.T) {
+	parser := &Qwen3Parser{hasThinkingSupport: true, defaultThinking: true}
+	parser.Init(nil, nil, &api.ThinkValue{Value: true})
+
+	input := "Let me think<tool_call>{\"name\":\"get_weather\",\"arguments\":{\"location\":\"San Francisco\",\"unit\":\"celsius\"}}</tool_call>"
+	content, thinking, calls, err := parser.Add(input, true)
+	if err != nil {
+		t.Fatalf("parse failed: %v", err)
+	}
+
+	if content != "" {
+		t.Fatalf("expected empty content, got %q", content)
+	}
+	if thinking != "Let me think" {
+		t.Fatalf("expected thinking %q, got %q", "Let me think", thinking)
+	}
+	if len(calls) != 1 {
+		t.Fatalf("expected 1 tool call, got %d", len(calls))
+	}
+	if calls[0].Function.Name != "get_weather" {
+		t.Fatalf("expected tool name %q, got %q", "get_weather", calls[0].Function.Name)
+	}
+}
+
+func TestQwen3ParserThinkingWithSplitToolOpenTag(t *testing.T) {
+	parser := &Qwen3Parser{hasThinkingSupport: true, defaultThinking: true}
+	parser.Init(nil, nil, &api.ThinkValue{Value: true})
+
+	content, thinking, calls, err := parser.Add("Let me think<tool_ca", false)
+	if err != nil {
+		t.Fatalf("parse failed on first chunk: %v", err)
+	}
+	if content != "" || thinking != "Let me think" || len(calls) != 0 {
+		t.Fatalf(
+			"expected content=%q thinking=%q calls=%d, got content=%q thinking=%q calls=%d",
+			"",
+			"Let me think",
+			0,
+			content,
+			thinking,
+			len(calls),
+		)
+	}
+
+	content, thinking, calls, err = parser.Add("ll>{\"name\":\"get_weather\",\"arguments\":{\"location\":\"SF\"}}</tool_call>", true)
+	if err != nil {
+		t.Fatalf("parse failed on second chunk: %v", err)
+	}
+	if content != "" {
+		t.Fatalf("expected empty content, got %q", content)
+	}
+	if thinking != "" {
+		t.Fatalf("expected no additional thinking on second chunk, got %q", thinking)
+	}
+	if len(calls) != 1 {
+		t.Fatalf("expected 1 tool call, got %d", len(calls))
+	}
+	if calls[0].Function.Name != "get_weather" {
+		t.Fatalf("expected tool name %q, got %q", "get_weather", calls[0].Function.Name)
+	}
+}
+
 func TestQwen35ParserRespectsNoThink(t *testing.T) {
 	parser := ParserForName("qwen3.5")
 	if parser == nil {

model/parsers/qwen3vl.go

@@ -180,7 +180,22 @@ func (p *Qwen3VLParser) eat() ([]qwenEvent, bool) {
 			return events, false
 		}
 	case CollectingThinkingContent:
-		if strings.Contains(p.buffer.String(), thinkingCloseTag) {
+		acc := p.buffer.String()
+		thinkingCloseIdx := strings.Index(acc, thinkingCloseTag)
+		toolOpenIdx := strings.Index(acc, toolOpenTag)
+
+		// If a tool call starts before </think>, treat that as the end of thinking
+		// for parsing purposes and continue in tool-call mode.
+		if toolOpenIdx != -1 && (thinkingCloseIdx == -1 || toolOpenIdx < thinkingCloseIdx) {
+			before, _ := splitAtTag(&p.buffer, toolOpenTag, false)
+			if len(before) > 0 {
+				events = append(events, qwenEventThinkingContent{content: before})
+			}
+			p.state = CollectingToolContent
+			return events, true
+		}
+
+		if strings.Contains(acc, thinkingCloseTag) {
 			thinking, remaining := splitAtTag(&p.buffer, thinkingCloseTag, true)
 			if len(thinking) > 0 {
 				events = append(events, qwenEventThinkingContent{content: thinking})
@@ -191,13 +206,13 @@ func (p *Qwen3VLParser) eat() ([]qwenEvent, bool) {
 				p.state = CollectingContent
 			}
 			return events, true
-		} else if overlapLen := overlap(p.buffer.String(), thinkingCloseTag); overlapLen > 0 {
-			beforePartialTag := p.buffer.String()[:len(p.buffer.String())-overlapLen]
+		} else if overlapLen := max(overlap(acc, thinkingCloseTag), overlap(acc, toolOpenTag)); overlapLen > 0 {
+			beforePartialTag := acc[:len(acc)-overlapLen]
 			trailingWhitespaceLen := trailingWhitespaceLen(beforePartialTag)
 			ambiguousStart := len(beforePartialTag) - trailingWhitespaceLen
 
-			unambiguous := p.buffer.String()[:ambiguousStart]
-			ambiguous := p.buffer.String()[ambiguousStart:]
+			unambiguous := acc[:ambiguousStart]
+			ambiguous := acc[ambiguousStart:]
 			p.buffer.Reset()
 			p.buffer.WriteString(ambiguous)
 			if len(unambiguous) > 0 {
@@ -205,11 +220,11 @@ func (p *Qwen3VLParser) eat() ([]qwenEvent, bool) {
 			}
 			return events, false
 		} else {
-			whitespaceLen := trailingWhitespaceLen(p.buffer.String())
-			ambiguousStart := len(p.buffer.String()) - whitespaceLen
+			whitespaceLen := trailingWhitespaceLen(acc)
+			ambiguousStart := len(acc) - whitespaceLen
 
-			unambiguous := p.buffer.String()[:ambiguousStart]
-			ambiguous := p.buffer.String()[ambiguousStart:]
+			unambiguous := acc[:ambiguousStart]
+			ambiguous := acc[ambiguousStart:]
 			p.buffer.Reset()
 			p.buffer.WriteString(ambiguous)
 			if len(unambiguous) > 0 {

model/parsers/qwen3vl_thinking_test.go

@@ -98,8 +98,12 @@ func TestQwen3VLThinkingParserStreaming(t *testing.T) {
 			desc: "nested thinking and tool call (outside thinking, inside tool call)",
 			steps: []step{
 				{
-					input:      "I'm thinking<tool_call>I'm nested tool call</tool_call></think>",
-					wantEvents: []qwenEvent{qwenEventThinkingContent{content: "I'm thinking<tool_call>I'm nested tool call</tool_call>"}},
+					input: "I'm thinking<tool_call>I'm nested tool call</tool_call></think>",
+					wantEvents: []qwenEvent{
+						qwenEventThinkingContent{content: "I'm thinking"},
+						qwenEventRawToolCall{raw: "I'm nested tool call"},
+						qwenEventContent{content: "</think>"},
+					},
 				},
 			},
 		},
@@ -109,8 +113,7 @@ func TestQwen3VLThinkingParserStreaming(t *testing.T) {
 				{
 					input: "<tool_call>I'm nested tool call<think>I'm thinking</think></tool_call>",
 					wantEvents: []qwenEvent{
-						qwenEventThinkingContent{content: "<tool_call>I'm nested tool call<think>I'm thinking"},
-						qwenEventContent{content: "</tool_call>"},
+						qwenEventRawToolCall{raw: "I'm nested tool call<think>I'm thinking</think>"},
 					},
 				},
 			},
@@ -121,8 +124,8 @@ func TestQwen3VLThinkingParserStreaming(t *testing.T) {
 				{
 					input: "I'm thinking<tool_call>I'm NOT a nested tool call</think></tool_call><tool_call>I'm nested tool call 2<think></tool_call></think>",
 					wantEvents: []qwenEvent{
-						qwenEventThinkingContent{content: "I'm thinking<tool_call>I'm NOT a nested tool call"},
-						qwenEventContent{content: "</tool_call>"},
+						qwenEventThinkingContent{content: "I'm thinking"},
+						qwenEventRawToolCall{raw: "I'm NOT a nested tool call</think>"},
 						qwenEventRawToolCall{raw: "I'm nested tool call 2<think>"},
 						qwenEventContent{content: "</think>"},
 					},

x/mlxrunner/cache.go

@@ -78,6 +78,11 @@ func (c *kvCache) findRemaining(tokens []int32) []int32 {
 		prefix++
 	}
 
+	if prefix == len(tokens) && prefix > 0 {
+		// Leave one token to run through the model so we can sample a response.
+		prefix--
+	}
+
 	if prefix < len(c.tokens) {
 		trim := len(c.tokens) - prefix
 		for _, kv := range c.caches {