parsers/renderers: olmo3 think (#13290)

model/parsers/olmo3_think.go

+package parsers
+
+import (
+	"context"
+	"log/slog"
+	"strings"
+	"unicode"
+
+	"github.com/ollama/ollama/api"
+	"github.com/ollama/ollama/logutil"
+)
+
+type olmo3ThinkParserState int
+
+const (
+	olmo3CollectingThink olmo3ThinkParserState = iota
+	olmo3CollectingContent
+)
+
+const (
+	olmo3ThinkCloseTag = "</think>"
+)
+
+type Olmo3ThinkParser struct {
+	state  olmo3ThinkParserState
+	buffer strings.Builder
+}
+
+func (p *Olmo3ThinkParser) HasToolSupport() bool {
+	return false
+}
+
+func (p *Olmo3ThinkParser) HasThinkingSupport() bool {
+	return true
+}
+
+func (p *Olmo3ThinkParser) setInitialState(lastMessage *api.Message) {
+	prefill := lastMessage != nil && lastMessage.Role == "assistant"
+
+	// If prefilling with content, skip to content collection
+	if prefill && lastMessage.Content != "" {
+		p.state = olmo3CollectingContent
+		return
+	}
+
+	// Model always thinks first (the <think> tag is injected in the prompt)
+	p.state = olmo3CollectingThink
+}
+
+func (p *Olmo3ThinkParser) Init(tools []api.Tool, lastMessage *api.Message, thinkValue *api.ThinkValue) []api.Tool {
+	p.setInitialState(lastMessage)
+	return tools
+}
+
+// Event types for internal parser communication
+type olmo3Event interface {
+	isOlmo3Event()
+}
+
+type olmo3EventThinkContent struct {
+	content string
+}
+
+type olmo3EventContent struct {
+	content string
+}
+
+func (olmo3EventThinkContent) isOlmo3Event() {}
+func (olmo3EventContent) isOlmo3Event()      {}
+
+func (p *Olmo3ThinkParser) Add(s string, done bool) (content string, thinking string, calls []api.ToolCall, err error) {
+	p.buffer.WriteString(s)
+	events := p.parseEvents()
+
+	var contentSb strings.Builder
+	var thinkingSb strings.Builder
+	for _, event := range events {
+		switch event := event.(type) {
+		case olmo3EventThinkContent:
+			thinkingSb.WriteString(event.content)
+		case olmo3EventContent:
+			contentSb.WriteString(event.content)
+		}
+	}
+
+	return contentSb.String(), thinkingSb.String(), nil, nil
+}
+
+func (p *Olmo3ThinkParser) parseEvents() []olmo3Event {
+	var all []olmo3Event
+
+	keepLooping := true
+	for keepLooping {
+		var events []olmo3Event
+		events, keepLooping = p.eat()
+		if len(events) > 0 {
+			all = append(all, events...)
+		}
+	}
+
+	if len(all) > 0 {
+		slog.Log(context.TODO(), logutil.LevelTrace, "olmo3 events parsed", "events", all, "state", p.state, "buffer", p.buffer.String())
+	}
+
+	return all
+}
+
+func (p *Olmo3ThinkParser) eat() ([]olmo3Event, bool) {
+	var events []olmo3Event
+	bufStr := p.buffer.String()
+	if bufStr == "" {
+		return events, false
+	}
+
+	switch p.state {
+	case olmo3CollectingThink:
+		if strings.Contains(bufStr, olmo3ThinkCloseTag) {
+			// Found complete </think> tag
+			split := strings.SplitN(bufStr, olmo3ThinkCloseTag, 2)
+			thinking := strings.TrimRightFunc(split[0], unicode.IsSpace)
+			remaining := strings.TrimLeftFunc(split[1], unicode.IsSpace)
+
+			p.buffer.Reset()
+			p.buffer.WriteString(remaining)
+			p.state = olmo3CollectingContent
+
+			if len(thinking) > 0 {
+				events = append(events, olmo3EventThinkContent{content: thinking})
+			}
+			return events, true
+		} else if overlapLen := overlap(bufStr, olmo3ThinkCloseTag); overlapLen > 0 {
+			// Partial </think> tag - withhold ambiguous content
+			beforePartialTag := bufStr[:len(bufStr)-overlapLen]
+			trailingLen := trailingWhitespaceLen(beforePartialTag)
+			ambiguousStart := len(beforePartialTag) - trailingLen
+
+			unambiguous := bufStr[:ambiguousStart]
+			ambiguous := bufStr[ambiguousStart:]
+			p.buffer.Reset()
+			p.buffer.WriteString(ambiguous)
+			if len(unambiguous) > 0 {
+				events = append(events, olmo3EventThinkContent{content: unambiguous})
+			}
+			return events, false
+		} else {
+			// Regular thinking content - withhold trailing whitespace in case </think> follows
+			whitespaceLen := trailingWhitespaceLen(bufStr)
+			ambiguousStart := len(bufStr) - whitespaceLen
+
+			unambiguous := bufStr[:ambiguousStart]
+			ambiguous := bufStr[ambiguousStart:]
+			p.buffer.Reset()
+			p.buffer.WriteString(ambiguous)
+			if len(unambiguous) > 0 {
+				events = append(events, olmo3EventThinkContent{content: unambiguous})
+			}
+			return events, false
+		}
+
+	case olmo3CollectingContent:
+		// Emit all content directly
+		p.buffer.Reset()
+		if len(bufStr) > 0 {
+			events = append(events, olmo3EventContent{content: bufStr})
+		}
+		return events, false
+	}
+
+	return events, false
+}

model/parsers/olmo3_think_test.go

+package parsers
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+
+	"github.com/ollama/ollama/api"
+)
+
+func TestOlmo3ThinkParser(t *testing.T) {
+	tests := []struct {
+		name             string
+		input            string
+		expectedContent  string
+		expectedThinking string
+		lastMessage      *api.Message
+	}{
+		{
+			name:             "thinking_only",
+			input:            "I need to think about this.</think>Here is my response.",
+			expectedContent:  "Here is my response.",
+			expectedThinking: "I need to think about this.",
+		},
+		{
+			name:             "thinking_with_newlines",
+			input:            "Let me think step by step.\n\n1. First point\n2. Second point</think>The answer is 42.",
+			expectedContent:  "The answer is 42.",
+			expectedThinking: "Let me think step by step.\n\n1. First point\n2. Second point",
+		},
+		{
+			name:             "thinking_then_content",
+			input:            "Deep thinking here.</think>Here is my detailed response with multiple sentences. I have thought carefully.",
+			expectedContent:  "Here is my detailed response with multiple sentences. I have thought carefully.",
+			expectedThinking: "Deep thinking here.",
+		},
+		{
+			name:             "empty_thinking",
+			input:            "</think>Just content here.",
+			expectedContent:  "Just content here.",
+			expectedThinking: "",
+		},
+		{
+			name:            "prefill_skips_thinking",
+			input:           "Continuing from previous content.",
+			expectedContent: "Continuing from previous content.",
+			lastMessage: &api.Message{
+				Role:    "assistant",
+				Content: "Previous content",
+			},
+		},
+		{
+			name:             "thinking_with_whitespace",
+			input:            "  Some thinking  </think>  Content here  ",
+			expectedContent:  "Content here  ",
+			expectedThinking: "  Some thinking",
+		},
+		{
+			name:             "real_model_output_with_newlines",
+			input:            "Yes, that should work. Let me go with that response.\n\n</think>\n\nHi! I'm all set and ready to assist. How about you? How are you today? 😊",
+			expectedThinking: "Yes, that should work. Let me go with that response.",
+			expectedContent:  "Hi! I'm all set and ready to assist. How about you? How are you today? 😊",
+		},
+		// Edge cases
+		{
+			name:             "nested_think_tags_in_thinking",
+			input:            "I'm thinking <think>nested</think> more thinking</think>Final content.",
+			expectedContent:  "more thinking</think>Final content.",
+			expectedThinking: "I'm thinking <think>nested",
+		},
+		{
+			name:             "multiple_think_close_tags",
+			input:            "First thinking</think>Content</think>More content.",
+			expectedContent:  "Content</think>More content.",
+			expectedThinking: "First thinking",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			parser := &Olmo3ThinkParser{}
+			parser.Init(nil, tt.lastMessage, nil)
+
+			content, thinking, toolCalls, err := parser.Add(tt.input, true)
+			if err != nil {
+				t.Fatalf("Add() error = %v", err)
+			}
+
+			if diff := cmp.Diff(tt.expectedContent, content); diff != "" {
+				t.Errorf("content mismatch (-want +got):\n%s", diff)
+			}
+
+			if diff := cmp.Diff(tt.expectedThinking, thinking); diff != "" {
+				t.Errorf("thinking mismatch (-want +got):\n%s", diff)
+			}
+
+			// No tool calls expected
+			if len(toolCalls) > 0 {
+				t.Errorf("expected no tool calls, got %d", len(toolCalls))
+			}
+		})
+	}
+}
+
+func TestOlmo3ThinkParser_Streaming(t *testing.T) {
+	parser := &Olmo3ThinkParser{}
+	parser.Init(nil, nil, nil)
+
+	chunks := []string{
+		"I am ",
+		"thinking about",
+		" this.</think>Here ",
+		"is the response.",
+	}
+
+	var finalContent, finalThinking strings.Builder
+
+	for i, chunk := range chunks {
+		done := i == len(chunks)-1
+		content, thinking, _, err := parser.Add(chunk, done)
+		if err != nil {
+			t.Fatalf("Add() error on chunk %d: %v", i, err)
+		}
+
+		finalContent.WriteString(content)
+		finalThinking.WriteString(thinking)
+	}
+
+	expectedContent := "Here is the response."
+	expectedThinking := "I am thinking about this."
+
+	if finalContent.String() != expectedContent {
+		t.Errorf("expected content %q, got %q", expectedContent, finalContent.String())
+	}
+
+	if finalThinking.String() != expectedThinking {
+		t.Errorf("expected thinking %q, got %q", expectedThinking, finalThinking.String())
+	}
+}
+
+func TestOlmo3ThinkParser_StreamingEdgeCases(t *testing.T) {
+	tests := []struct {
+		name             string
+		chunks           []string
+		expectedContent  string
+		expectedThinking string
+	}{
+		{
+			name: "thinking_tag_split_across_chunks",
+			chunks: []string{
+				"This is thinking content",
+				"</think>",
+				"This is content.",
+			},
+			expectedContent:  "This is content.",
+			expectedThinking: "This is thinking content",
+		},
+		{
+			name: "thinking_tag_split_mid_token",
+			chunks: []string{
+				"Thinking?</",
+				"think>",
+				"Content here.",
+			},
+			expectedContent:  "Content here.",
+			expectedThinking: "Thinking?",
+		},
+		{
+			name: "thinking_tag_split_at_angle_bracket",
+			chunks: []string{
+				"Thinking<",
+				"/think>",
+				"Content.",
+			},
+			expectedContent:  "Content.",
+			expectedThinking: "Thinking",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			parser := &Olmo3ThinkParser{}
+			parser.Init(nil, nil, nil)
+
+			var finalContent, finalThinking strings.Builder
+
+			for i, chunk := range tt.chunks {
+				done := i == len(tt.chunks)-1
+				content, thinking, _, err := parser.Add(chunk, done)
+				if err != nil {
+					t.Fatalf("Add() error on chunk %d: %v", i, err)
+				}
+
+				finalContent.WriteString(content)
+				finalThinking.WriteString(thinking)
+			}
+
+			if finalContent.String() != tt.expectedContent {
+				t.Errorf("expected content %q, got %q", tt.expectedContent, finalContent.String())
+			}
+
+			if finalThinking.String() != tt.expectedThinking {
+				t.Errorf("expected thinking %q, got %q", tt.expectedThinking, finalThinking.String())
+			}
+		})
+	}
+}
+
+// TestOlmo3ThinkParser_ThinkBoundary tests streaming thinking content
+// where thinking chunks come in succession before the </think> tag
+func TestOlmo3ThinkParser_ThinkBoundary(t *testing.T) {
+	tests := []struct {
+		name             string
+		chunks           []string
+		expectedThinking string
+		expectedContent  string
+	}{
+		{
+			name: "multiple_thinking_chunks",
+			chunks: []string{
+				"First part of thinking. ",
+				"Second part of thinking. ",
+				"Third part.</think>",
+				"Content here.",
+			},
+			expectedThinking: "First part of thinking. Second part of thinking. Third part.",
+			expectedContent:  "Content here.",
+		},
+		{
+			name: "thinking_chunks_with_newlines",
+			chunks: []string{
+				"Step 1: Analyze the problem.\n",
+				"Step 2: Consider options.\n",
+				"Step 3: Make decision.</think>",
+				"Here is my answer.",
+			},
+			expectedThinking: "Step 1: Analyze the problem.\nStep 2: Consider options.\nStep 3: Make decision.",
+			expectedContent:  "Here is my answer.",
+		},
+		{
+			name: "single_char_thinking_chunks",
+			chunks: []string{
+				"H", "e", "l", "l", "o", "</think>", "World",
+			},
+			expectedThinking: "Hello",
+			expectedContent:  "World",
+		},
+		{
+			name: "thinking_with_special_chars",
+			chunks: []string{
+				"Let me think... ",
+				"Option A: $100 ",
+				"Option B: €200</think>",
+				"I recommend Option A.",
+			},
+			expectedThinking: "Let me think... Option A: $100 Option B: €200",
+			expectedContent:  "I recommend Option A.",
+		},
+		{
+			name: "long_thinking_multiple_chunks",
+			chunks: []string{
+				"This is a very long thinking process. ",
+				"I need to consider many factors. ",
+				"First, let me look at the data. ",
+				"The numbers show interesting patterns. ",
+				"Based on my analysis, ",
+				"I can conclude that...</think>",
+				"The answer is 42.",
+			},
+			expectedThinking: "This is a very long thinking process. I need to consider many factors. First, let me look at the data. The numbers show interesting patterns. Based on my analysis, I can conclude that...",
+			expectedContent:  "The answer is 42.",
+		},
+		{
+			name: "thinking_ends_exactly_at_chunk_boundary",
+			chunks: []string{
+				"Thinking content",
+				"</think>",
+				"Content",
+			},
+			expectedThinking: "Thinking content",
+			expectedContent:  "Content",
+		},
+		{
+			name: "empty_chunks_between_thinking",
+			chunks: []string{
+				"Start thinking",
+				"",
+				" middle ",
+				"",
+				"end</think>",
+				"Content",
+			},
+			expectedThinking: "Start thinking middle end",
+			expectedContent:  "Content",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			parser := &Olmo3ThinkParser{}
+			parser.Init(nil, nil, nil)
+
+			var finalContent, finalThinking strings.Builder
+
+			for i, chunk := range tt.chunks {
+				done := i == len(tt.chunks)-1
+				content, thinking, _, err := parser.Add(chunk, done)
+				if err != nil {
+					t.Fatalf("Add() error on chunk %d: %v", i, err)
+				}
+
+				finalContent.WriteString(content)
+				finalThinking.WriteString(thinking)
+			}
+
+			if finalThinking.String() != tt.expectedThinking {
+				t.Errorf("thinking mismatch:\nexpected: %q\ngot:      %q", tt.expectedThinking, finalThinking.String())
+			}
+
+			if finalContent.String() != tt.expectedContent {
+				t.Errorf("content mismatch:\nexpected: %q\ngot:      %q", tt.expectedContent, finalContent.String())
+			}
+		})
+	}
+}
+
+// TestOlmo3ThinkParser_StateTransitions tests that state transitions work correctly
+func TestOlmo3ThinkParser_StateTransitions(t *testing.T) {
+	t.Run("thinking_to_content", func(t *testing.T) {
+		parser := &Olmo3ThinkParser{}
+		parser.Init(nil, nil, nil)
+
+		if parser.state != olmo3CollectingThink {
+			t.Errorf("initial state should be olmo3CollectingThink, got %v", parser.state)
+		}
+
+		parser.Add("thinking</think>content", true)
+
+		if parser.state != olmo3CollectingContent {
+			t.Errorf("state after </think> should be olmo3CollectingContent, got %v", parser.state)
+		}
+	})
+}
+
+func TestOlmo3ThinkParser_HasToolSupport(t *testing.T) {
+	parser := &Olmo3ThinkParser{}
+	if parser.HasToolSupport() {
+		t.Error("Olmo3ThinkParser should NOT support tools")
+	}
+}
+
+func TestOlmo3ThinkParser_HasThinkingSupport(t *testing.T) {
+	parser := &Olmo3ThinkParser{}
+	if !parser.HasThinkingSupport() {
+		t.Error("Olmo3ThinkParser should support thinking")
+	}
+}
+
+func TestOlmo3ThinkParser_Init(t *testing.T) {
+	parser := &Olmo3ThinkParser{}
+
+	tools := []api.Tool{
+		{Function: api.ToolFunction{Name: "test_tool"}},
+	}
+
+	lastMessage := &api.Message{Role: "assistant", Content: "previous"}
+
+	returnedTools := parser.Init(tools, lastMessage, nil)
+
+	if len(returnedTools) != len(tools) {
+		t.Errorf("expected %d tools returned, got %d", len(tools), len(returnedTools))
+	}
+
+	// Should be in content collection mode due to prefill
+	if parser.state != olmo3CollectingContent {
+		t.Errorf("expected state olmo3CollectingContent, got %v", parser.state)
+	}
+}
+
+func TestOlmo3ThinkParser_InitWithoutPrefill(t *testing.T) {
+	parser := &Olmo3ThinkParser{}
+
+	parser.Init(nil, nil, nil)
+
+	// Should be in thinking collection mode (model always thinks first)
+	if parser.state != olmo3CollectingThink {
+		t.Errorf("expected state olmo3CollectingThink, got %v", parser.state)
+	}
+}

model/parsers/parsers.go

@@ -58,6 +58,8 @@ func ParserForName(name string) Parser {
 		return harmony.NewHarmonyMessageHandler()
 	case "cogito":
 		return &CogitoParser{}
+	case "olmo3-think":
+		return &Olmo3ThinkParser{}
 	default:
 		return nil
 	}

model/renderers/json.go

+package renderers
+
+import "encoding/json"
+
+// marshalWithSpaces marshals v to JSON and adds a space after each ':' and ','
+// that appears outside of string values. This matches the formatting expected
+// by certain model architectures.
+func marshalWithSpaces(v any) ([]byte, error) {
+	b, err := json.Marshal(v)
+	if err != nil {
+		return nil, err
+	}
+
+	out := make([]byte, 0, len(b)+len(b)/8)
+	inStr, esc := false, false
+	for _, c := range b {
+		if inStr {
+			out = append(out, c)
+			if esc {
+				esc = false
+				continue
+			}
+			if c == '\\' {
+				esc = true
+				continue
+			}
+			if c == '"' {
+				inStr = false
+			}
+			continue
+		}
+		switch c {
+		case '"':
+			inStr = true
+			out = append(out, c)
+		case ':':
+			out = append(out, ':', ' ')
+		case ',':
+			out = append(out, ',', ' ')
+		default:
+			out = append(out, c)
+		}
+	}
+	return out, nil
+}

model/renderers/qwen3vl_test.go → model/renderers/json_test.go

@@ -6,7 +6,6 @@ import (
 	"github.com/google/go-cmp/cmp"
 )
 
-// TODO(drifkin): this will be moved to utils in the near future and used by other renderers as well
 func TestMarshalWithSpaces(t *testing.T) {
 	tests := []struct {
 		name     string

model/renderers/olmo3_think.go

+package renderers
+
+import (
+	"encoding/json"
+	"strings"
+
+	"github.com/ollama/ollama/api"
+)
+
+const (
+	olmo3ThinkDefaultSystemMessage = "You are OLMo, a helpful function-calling AI assistant built by Ai2. Your date cutoff is November 2024, and your model weights are available at https://huggingface.co/allenai."
+	olmo3ThinkNoFunctionsMessage   = " You do not currently have access to any functions."
+)
+
+type Olmo3ThinkRenderer struct{}
+
+type olmo3ThinkToolCall struct {
+	ID       string                 `json:"id,omitempty"`
+	Type     string                 `json:"type,omitempty"`
+	Function olmo3ThinkToolCallFunc `json:"function"`
+}
+
+type olmo3ThinkToolCallFunc struct {
+	Name      string `json:"name"`
+	Arguments string `json:"arguments"`
+}
+
+func (r *Olmo3ThinkRenderer) Render(messages []api.Message, tools []api.Tool, _ *api.ThinkValue) (string, error) {
+	var sb strings.Builder
+
+	var systemMessage *api.Message
+	filteredMessages := make([]api.Message, 0, len(messages))
+	for i, message := range messages {
+		if message.Role == "system" {
+			if systemMessage == nil {
+				systemMessage = &messages[i]
+			}
+			continue
+		}
+		filteredMessages = append(filteredMessages, message)
+	}
+
+	systemContent := olmo3ThinkDefaultSystemMessage
+	if systemMessage != nil {
+		systemContent = systemMessage.Content
+	}
+
+	sb.WriteString("<|im_start|>system\n")
+	sb.WriteString(systemContent)
+
+	if len(tools) > 0 {
+		functionsJSON, err := marshalWithSpaces(tools)
+		if err != nil {
+			return "", err
+		}
+		sb.WriteString(" <functions>")
+		sb.WriteString(string(functionsJSON))
+		sb.WriteString("</functions>")
+	} else {
+		sb.WriteString(olmo3ThinkNoFunctionsMessage)
+		sb.WriteString(" <functions></functions>")
+	}
+	sb.WriteString("<|im_end|>\n")
+
+	for i, message := range filteredMessages {
+		lastMessage := i == len(filteredMessages)-1
+
+		switch message.Role {
+		case "user":
+			sb.WriteString("<|im_start|>user\n")
+			sb.WriteString(message.Content)
+			sb.WriteString("<|im_end|>\n")
+
+		case "assistant":
+			sb.WriteString("<|im_start|>assistant\n")
+
+			if message.Content != "" {
+				sb.WriteString(message.Content)
+			}
+
+			if len(message.ToolCalls) > 0 {
+				toolCalls := make([]olmo3ThinkToolCall, len(message.ToolCalls))
+				for j, tc := range message.ToolCalls {
+					argsJSON, err := json.Marshal(tc.Function.Arguments)
+					if err != nil {
+						return "", err
+					}
+					toolCalls[j] = olmo3ThinkToolCall{
+						ID:   tc.ID,
+						Type: "function",
+						Function: olmo3ThinkToolCallFunc{
+							Name:      tc.Function.Name,
+							Arguments: string(argsJSON),
+						},
+					}
+				}
+				toolCallsJSON, err := marshalWithSpaces(toolCalls)
+				if err != nil {
+					return "", err
+				}
+				sb.WriteString("<function_calls>")
+				sb.WriteString(string(toolCallsJSON))
+				sb.WriteString("</function_calls>")
+			}
+
+			if !lastMessage {
+				sb.WriteString("<|im_end|>\n")
+			}
+
+		case "tool":
+			sb.WriteString("<|im_start|>environment\n")
+			sb.WriteString(message.Content)
+			sb.WriteString("<|im_end|>\n")
+		}
+	}
+
+	needsGenerationPrompt := true
+	if len(filteredMessages) > 0 {
+		lastMsg := filteredMessages[len(filteredMessages)-1]
+		if lastMsg.Role == "assistant" && len(lastMsg.ToolCalls) == 0 && lastMsg.Content != "" {
+			needsGenerationPrompt = false
+		}
+	}
+
+	if needsGenerationPrompt {
+		sb.WriteString("<|im_start|>assistant\n<think>")
+	}
+
+	return sb.String(), nil
+}

model/renderers/olmo3_think_test.go

+package renderers
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+
+	"github.com/ollama/ollama/api"
+)
+
+func TestOlmo3ThinkRenderer(t *testing.T) {
+	tests := []struct {
+		name     string
+		msgs     []api.Message
+		tools    []api.Tool
+		expected string
+	}{
+		{
+			name: "basic without system - adds default system",
+			msgs: []api.Message{
+				{Role: "user", Content: "Hello!"},
+			},
+			expected: "<|im_start|>system\n" +
+				"You are OLMo, a helpful function-calling AI assistant built by Ai2. Your date cutoff is November 2024, and your model weights are available at https://huggingface.co/allenai. You do not currently have access to any functions. <functions></functions><|im_end|>\n" +
+				"<|im_start|>user\n" +
+				"Hello!<|im_end|>\n" +
+				"<|im_start|>assistant\n" +
+				"<think>",
+		},
+		{
+			name: "with system message no tools",
+			msgs: []api.Message{
+				{Role: "system", Content: "You are a helpful assistant."},
+				{Role: "user", Content: "Hello!"},
+			},
+			expected: "<|im_start|>system\n" +
+				"You are a helpful assistant. You do not currently have access to any functions. <functions></functions><|im_end|>\n" +
+				"<|im_start|>user\n" +
+				"Hello!<|im_end|>\n" +
+				"<|im_start|>assistant\n" +
+				"<think>",
+		},
+		{
+			name: "with system message and tools",
+			msgs: []api.Message{
+				{Role: "system", Content: "You are a helpful assistant."},
+				{Role: "user", Content: "What is the weather?"},
+			},
+			tools: []api.Tool{
+				{
+					Type: "function",
+					Function: api.ToolFunction{
+						Name:        "get_weather",
+						Description: "Get the current weather",
+						Parameters: api.ToolFunctionParameters{
+							Type:     "object",
+							Required: []string{"location"},
+							Properties: map[string]api.ToolProperty{
+								"location": {Type: api.PropertyType{"string"}, Description: "The city"},
+							},
+						},
+					},
+				},
+			},
+			expected: "<|im_start|>system\n" +
+				`You are a helpful assistant. <functions>[{"type": "function", "function": {"name": "get_weather", "description": "Get the current weather", "parameters": {"type": "object", "required": ["location"], "properties": {"location": {"type": "string", "description": "The city"}}}}}]</functions><|im_end|>` + "\n" +
+				"<|im_start|>user\n" +
+				"What is the weather?<|im_end|>\n" +
+				"<|im_start|>assistant\n" +
+				"<think>",
+		},
+		{
+			name: "assistant with tool calls",
+			msgs: []api.Message{
+				{Role: "system", Content: "You are a helpful assistant."},
+				{Role: "user", Content: "What is the weather in SF?"},
+				{
+					Role:    "assistant",
+					Content: "Let me check the weather.",
+					ToolCalls: []api.ToolCall{
+						{
+							ID: "call_1",
+							Function: api.ToolCallFunction{
+								Name: "get_weather",
+								Arguments: map[string]any{
+									"location": "San Francisco",
+								},
+							},
+						},
+					},
+				},
+				{Role: "tool", Content: `{"temperature": 68}`, ToolName: "get_weather"},
+			},
+			tools: []api.Tool{
+				{
+					Type: "function",
+					Function: api.ToolFunction{
+						Name:        "get_weather",
+						Description: "Get the current weather",
+						Parameters: api.ToolFunctionParameters{
+							Type:     "object",
+							Required: []string{"location"},
+							Properties: map[string]api.ToolProperty{
+								"location": {Type: api.PropertyType{"string"}, Description: "The city"},
+							},
+						},
+					},
+				},
+			},
+			expected: "<|im_start|>system\n" +
+				`You are a helpful assistant. <functions>[{"type": "function", "function": {"name": "get_weather", "description": "Get the current weather", "parameters": {"type": "object", "required": ["location"], "properties": {"location": {"type": "string", "description": "The city"}}}}}]</functions><|im_end|>` + "\n" +
+				"<|im_start|>user\n" +
+				"What is the weather in SF?<|im_end|>\n" +
+				"<|im_start|>assistant\n" +
+				`Let me check the weather.<function_calls>[{"id": "call_1", "type": "function", "function": {"name": "get_weather", "arguments": "{\"location\":\"San Francisco\"}"}}]</function_calls><|im_end|>` + "\n" +
+				"<|im_start|>environment\n" +
+				`{"temperature": 68}<|im_end|>` + "\n" +
+				"<|im_start|>assistant\n" +
+				"<think>",
+		},
+		{
+			name: "multi-turn conversation",
+			msgs: []api.Message{
+				{Role: "system", Content: "You are a helpful assistant."},
+				{Role: "user", Content: "Hello"},
+				{Role: "assistant", Content: "Hi there!"},
+				{Role: "user", Content: "How are you?"},
+			},
+			expected: "<|im_start|>system\n" +
+				"You are a helpful assistant. You do not currently have access to any functions. <functions></functions><|im_end|>\n" +
+				"<|im_start|>user\n" +
+				"Hello<|im_end|>\n" +
+				"<|im_start|>assistant\n" +
+				"Hi there!<|im_end|>\n" +
+				"<|im_start|>user\n" +
+				"How are you?<|im_end|>\n" +
+				"<|im_start|>assistant\n" +
+				"<think>",
+		},
+		{
+			name: "parallel tool calls",
+			msgs: []api.Message{
+				{Role: "user", Content: "Get weather in SF and NYC"},
+				{
+					Role: "assistant",
+					ToolCalls: []api.ToolCall{
+						{
+							ID: "call_1",
+							Function: api.ToolCallFunction{
+								Name:      "get_weather",
+								Arguments: map[string]any{"location": "San Francisco"},
+							},
+						},
+						{
+							ID: "call_2",
+							Function: api.ToolCallFunction{
+								Name:      "get_weather",
+								Arguments: map[string]any{"location": "New York"},
+							},
+						},
+					},
+				},
+				{Role: "tool", Content: `{"temperature": 68}`, ToolName: "get_weather"},
+				{Role: "tool", Content: `{"temperature": 55}`, ToolName: "get_weather"},
+			},
+			tools: []api.Tool{
+				{
+					Type: "function",
+					Function: api.ToolFunction{
+						Name: "get_weather",
+						Parameters: api.ToolFunctionParameters{
+							Type: "object",
+							Properties: map[string]api.ToolProperty{
+								"location": {Type: api.PropertyType{"string"}},
+							},
+						},
+					},
+				},
+			},
+			expected: "<|im_start|>system\n" +
+				`You are OLMo, a helpful function-calling AI assistant built by Ai2. Your date cutoff is November 2024, and your model weights are available at https://huggingface.co/allenai. <functions>[{"type": "function", "function": {"name": "get_weather", "parameters": {"type": "object", "properties": {"location": {"type": "string"}}}}}]</functions><|im_end|>` + "\n" +
+				"<|im_start|>user\n" +
+				"Get weather in SF and NYC<|im_end|>\n" +
+				"<|im_start|>assistant\n" +
+				`<function_calls>[{"id": "call_1", "type": "function", "function": {"name": "get_weather", "arguments": "{\"location\":\"San Francisco\"}"}}, {"id": "call_2", "type": "function", "function": {"name": "get_weather", "arguments": "{\"location\":\"New York\"}"}}]</function_calls><|im_end|>` + "\n" +
+				"<|im_start|>environment\n" +
+				`{"temperature": 68}<|im_end|>` + "\n" +
+				"<|im_start|>environment\n" +
+				`{"temperature": 55}<|im_end|>` + "\n" +
+				"<|im_start|>assistant\n" +
+				"<think>",
+		},
+		{
+			name: "assistant message only content no tool calls",
+			msgs: []api.Message{
+				{Role: "user", Content: "Tell me a joke"},
+				{Role: "assistant", Content: "Why did the chicken cross the road?"},
+				{Role: "user", Content: "I don't know, why?"},
+			},
+			expected: "<|im_start|>system\n" +
+				"You are OLMo, a helpful function-calling AI assistant built by Ai2. Your date cutoff is November 2024, and your model weights are available at https://huggingface.co/allenai. You do not currently have access to any functions. <functions></functions><|im_end|>\n" +
+				"<|im_start|>user\n" +
+				"Tell me a joke<|im_end|>\n" +
+				"<|im_start|>assistant\n" +
+				"Why did the chicken cross the road?<|im_end|>\n" +
+				"<|im_start|>user\n" +
+				"I don't know, why?<|im_end|>\n" +
+				"<|im_start|>assistant\n" +
+				"<think>",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			rendered, err := (&Olmo3ThinkRenderer{}).Render(tt.msgs, tt.tools, nil)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if diff := cmp.Diff(rendered, tt.expected); diff != "" {
+				t.Errorf("mismatch (-got +want):\n%s", diff)
+			}
+		})
+	}
+}

model/renderers/qwen3vl.go

 package renderers
 
 import (
-	"encoding/json"
 	"strings"
 
 	"github.com/ollama/ollama/api"
 )
 
-func marshalWithSpaces(v any) ([]byte, error) {
-	b, err := json.Marshal(v)
-	if err != nil {
-		return nil, err
-	}
-
-	out := make([]byte, 0, len(b)+len(b)/8)
-	inStr, esc := false, false
-	for _, c := range b {
-		if inStr {
-			out = append(out, c)
-			if esc {
-				esc = false
-				continue
-			}
-			if c == '\\' {
-				esc = true
-				continue
-			}
-			if c == '"' {
-				inStr = false
-			}
-			continue
-		}
-		switch c {
-		case '"':
-			inStr = true
-			out = append(out, c)
-		case ':':
-			out = append(out, ':', ' ')
-		case ',':
-			out = append(out, ',', ' ')
-		default:
-			out = append(out, c)
-		}
-	}
-	return out, nil
-}
-
 type Qwen3VLRenderer struct {
 	isThinking bool
 

model/renderers/renderer.go

@@ -59,6 +59,9 @@ func rendererForName(name string) Renderer {
 	case "cogito":
 		renderer := &CogitoRenderer{isThinking: true}
 		return renderer
+	case "olmo3-think":
+		renderer := &Olmo3ThinkRenderer{}
+		return renderer
 	default:
 		return nil
 	}