model/parsers: fix missing parallel tool call indices (#15467)

We were missing setting the function index for several models that can
make parallel tool calls.

In the future we may want to consider putting some sort of post-parse
hook and relieve the parsers of this duty.

Fixes: #15457

model/parsers/cogito.go

@@ -33,8 +33,9 @@ const (
 )
 
 type CogitoParser struct {
-	state  CogitoParserState
+	state     CogitoParserState
-	buffer strings.Builder
+	buffer    strings.Builder
+	callIndex int
 }
 
 func (p *CogitoParser) HasToolSupport() bool {
@@ -72,6 +73,7 @@ func (p *CogitoParser) setInitialState(lastMessage *api.Message, tools []api.Too
 }
 
 func (p *CogitoParser) Init(tools []api.Tool, lastMessage *api.Message, thinkValue *api.ThinkValue) []api.Tool {
+	p.callIndex = 0
 	p.setInitialState(lastMessage, tools, thinkValue)
 	return tools
 }
@@ -114,6 +116,11 @@ func (p *CogitoParser) Add(s string, done bool) (content string, thinking string
 		}
 	}
 
+	for i := range toolCalls {
+		toolCalls[i].Function.Index = p.callIndex
+		p.callIndex++
+	}
+
 	return contentSb.String(), thinkingSb.String(), toolCalls, nil
 }
 

model/parsers/cogito_test.go

@@ -39,7 +39,8 @@ func TestCogitoParser(t *testing.T) {
 			expectedToolCalls: []api.ToolCall{
 				{
 					Function: api.ToolCallFunction{
-						Name: "get_weather",
+						Index: 0,
+						Name:  "get_weather",
 						Arguments: testArgs(map[string]any{
 							"location": "Paris",
 						}),
@@ -110,7 +111,8 @@ func TestCogitoParser(t *testing.T) {
 				},
 				{
 					Function: api.ToolCallFunction{
-						Name: "get_weather",
+						Index: 1,
+						Name:  "get_weather",
 						Arguments: testArgs(map[string]any{
 							"location": "London",
 						}),

model/parsers/deepseek3.go

@@ -33,6 +33,7 @@ const (
 type DeepSeek3Parser struct {
 	state              DeepSeek3ParserState
 	buffer             strings.Builder
+	callIndex          int
 	hasThinkingSupport bool
 }
 
@@ -64,6 +65,7 @@ func (p *DeepSeek3Parser) setInitialState(lastMessage *api.Message, tools []api.
 }
 
 func (p *DeepSeek3Parser) Init(tools []api.Tool, lastMessage *api.Message, thinkValue *api.ThinkValue) []api.Tool {
+	p.callIndex = 0
 	p.setInitialState(lastMessage, tools, thinkValue)
 	return tools
 }
@@ -106,6 +108,11 @@ func (p *DeepSeek3Parser) Add(s string, done bool) (content string, thinking str
 		}
 	}
 
+	for i := range toolCalls {
+		toolCalls[i].Function.Index = p.callIndex
+		p.callIndex++
+	}
+
 	return contentSb.String(), thinkingSb.String(), toolCalls, nil
 }
 

model/parsers/deepseek3_test.go

@@ -50,7 +50,8 @@ func TestDeepSeekParser(t *testing.T) {
 			expectedCalls: []api.ToolCall{
 				{
 					Function: api.ToolCallFunction{
-						Name: "get_weather",
+						Index: 0,
+						Name:  "get_weather",
 						Arguments: testArgs(map[string]any{
 							"location": "Paris",
 						}),
@@ -74,7 +75,8 @@ func TestDeepSeekParser(t *testing.T) {
 				},
 				{
 					Function: api.ToolCallFunction{
-						Name: "get_weather",
+						Index: 1,
+						Name:  "get_weather",
 						Arguments: testArgs(map[string]any{
 							"location": "London",
 						}),

model/parsers/functiongemma.go

@@ -22,9 +22,10 @@ const (
 
 // This format uses <start_function_call>call:name{args}<end_function_call> for tool calls.
 type FunctionGemmaParser struct {
-	state  FunctionGemmaParserState
+	state     FunctionGemmaParserState
-	buffer strings.Builder
+	buffer    strings.Builder
-	tools  []api.Tool
+	tools     []api.Tool
+	callIndex int
 }
 
 func (p *FunctionGemmaParser) HasToolSupport() bool     { return true }
@@ -33,6 +34,7 @@ func (p *FunctionGemmaParser) HasThinkingSupport() bool { return false }
 func (p *FunctionGemmaParser) Init(tools []api.Tool, lastMessage *api.Message, thinkValue *api.ThinkValue) []api.Tool {
 	p.tools = tools
 	p.state = FunctionGemmaCollectingContent
+	p.callIndex = 0
 	return tools
 }
 
@@ -66,6 +68,11 @@ func (p *FunctionGemmaParser) Add(s string, done bool) (content string, thinking
 		}
 	}
 
+	for i := range toolCalls {
+		toolCalls[i].Function.Index = p.callIndex
+		p.callIndex++
+	}
+
 	return contentSb.String(), "", toolCalls, nil
 }
 

model/parsers/functiongemma_test.go

@@ -124,12 +124,14 @@ func TestFunctionGemmaParser(t *testing.T) {
 			expectedCalls: []api.ToolCall{
 				{
 					Function: api.ToolCallFunction{
+						Index:     0,
 						Name:      "get_weather",
 						Arguments: testArgs(map[string]any{"city": "Paris"}),
 					},
 				},
 				{
 					Function: api.ToolCallFunction{
+						Index:     1,
 						Name:      "get_weather",
 						Arguments: testArgs(map[string]any{"city": "London"}),
 					},
@@ -345,12 +347,14 @@ func TestFunctionGemmaParser(t *testing.T) {
 			expectedCalls: []api.ToolCall{
 				{
 					Function: api.ToolCallFunction{
+						Index:     0,
 						Name:      "get_weather",
 						Arguments: testArgs(map[string]any{"city": "Paris"}),
 					},
 				},
 				{
 					Function: api.ToolCallFunction{
+						Index:     1,
 						Name:      "get_time",
 						Arguments: testArgs(map[string]any{"timezone": "UTC"}),
 					},
@@ -372,12 +376,14 @@ func TestFunctionGemmaParser(t *testing.T) {
 			expectedCalls: []api.ToolCall{
 				{
 					Function: api.ToolCallFunction{
+						Index:     0,
 						Name:      "first",
 						Arguments: api.NewToolCallFunctionArguments(),
 					},
 				},
 				{
 					Function: api.ToolCallFunction{
+						Index:     1,
 						Name:      "second",
 						Arguments: api.NewToolCallFunctionArguments(),
 					},

model/parsers/gemma4.go

@@ -38,6 +38,7 @@ type Gemma4Parser struct {
 	state                 Gemma4ParserState
 	buffer                strings.Builder
 	tools                 []api.Tool
+	callIndex             int
 	hasThinkingSupport    bool
 	thinkingEnabled       bool // true when both model supports and user requested thinking
 	needsChannelNameStrip bool // true when we just entered thinking and need to strip "thought\n"
@@ -53,6 +54,7 @@ func (p *Gemma4Parser) HasThinkingSupport() bool {
 
 func (p *Gemma4Parser) Init(tools []api.Tool, lastMessage *api.Message, thinkValue *api.ThinkValue) []api.Tool {
 	p.tools = tools
+	p.callIndex = 0
 
 	prefill := lastMessage != nil && lastMessage.Role == "assistant"
 
@@ -116,6 +118,11 @@ func (p *Gemma4Parser) Add(s string, done bool) (content string, thinking string
 		}
 	}
 
+	for i := range toolCalls {
+		toolCalls[i].Function.Index = p.callIndex
+		p.callIndex++
+	}
+
 	return contentSb.String(), thinkingSb.String(), toolCalls, nil
 }
 

model/parsers/gemma4_test.go

@@ -290,7 +290,8 @@ func TestGemma4Parser(t *testing.T) {
 			expectedToolCalls: []api.ToolCall{
 				{
 					Function: api.ToolCallFunction{
-						Name: "get_weather",
+						Index: 0,
+						Name:  "get_weather",
 						Arguments: testArgs(map[string]any{
 							"location": "Paris",
 						}),
@@ -298,7 +299,8 @@ func TestGemma4Parser(t *testing.T) {
 				},
 				{
 					Function: api.ToolCallFunction{
-						Name: "get_weather",
+						Index: 1,
+						Name:  "get_weather",
 						Arguments: testArgs(map[string]any{
 							"location": "London",
 						}),

model/parsers/lfm2.go

@@ -29,6 +29,7 @@ const (
 type LFM2Parser struct {
 	state                    LFM2ParserState
 	buffer                   strings.Builder
+	callIndex                int
 	hasThinkingSupport       bool
 	needsThinkingLeadingTrim bool // trim leading whitespace after <think> tag
 	needsContentLeadingTrim  bool // trim leading whitespace after </think> tag
@@ -66,6 +67,7 @@ func (p *LFM2Parser) setInitialState(lastMessage *api.Message, thinkValue *api.T
 
 func (p *LFM2Parser) Init(tools []api.Tool, lastMessage *api.Message, thinkValue *api.ThinkValue) []api.Tool {
 	p.toolNames = make(map[string]struct{}, len(tools))
+	p.callIndex = 0
 	p.hasTools = len(tools) > 0
 	for _, tool := range tools {
 		if tool.Function.Name != "" {
@@ -123,6 +125,11 @@ func (p *LFM2Parser) Add(s string, done bool) (content string, thinking string,
 		}
 	}
 
+	for i := range toolCalls {
+		toolCalls[i].Function.Index = p.callIndex
+		p.callIndex++
+	}
+
 	return contentSb.String(), thinkingSb.String(), toolCalls, nil
 }
 

model/parsers/lfm2_test.go

@@ -60,7 +60,8 @@ func TestLFM2Parser(t *testing.T) {
 			expectedCalls: []api.ToolCall{
 				{
 					Function: api.ToolCallFunction{
-						Name: "get_weather",
+						Index: 0,
+						Name:  "get_weather",
 						Arguments: testArgs(map[string]any{
 							"location": "Paris",
 						}),
@@ -68,7 +69,8 @@ func TestLFM2Parser(t *testing.T) {
 				},
 				{
 					Function: api.ToolCallFunction{
-						Name: "get_weather",
+						Index: 1,
+						Name:  "get_weather",
 						Arguments: testArgs(map[string]any{
 							"location": "London",
 						}),
@@ -205,7 +207,8 @@ func TestLFM2Parser(t *testing.T) {
 			expectedCalls: []api.ToolCall{
 				{
 					Function: api.ToolCallFunction{
-						Name: "bash",
+						Index: 0,
+						Name:  "bash",
 						Arguments: testArgs(map[string]any{
 							"command": "ls",
 						}),
@@ -213,7 +216,8 @@ func TestLFM2Parser(t *testing.T) {
 				},
 				{
 					Function: api.ToolCallFunction{
-						Name: "bash",
+						Index: 1,
+						Name:  "bash",
 						Arguments: testArgs(map[string]any{
 							"command": "pwd",
 						}),

model/parsers/ministral.go

@@ -44,6 +44,7 @@ type MinistralParser struct {
 	state              ministralParserState
 	buffer             strings.Builder
 	tools              []api.Tool
+	callIndex          int
 	hasThinkingSupport bool
 	pendingToolName    string // stores tool name while collecting args
 }
@@ -73,6 +74,7 @@ func (p *MinistralParser) setInitialState(lastMessage *api.Message) {
 
 func (p *MinistralParser) Init(tools []api.Tool, lastMessage *api.Message, thinkValue *api.ThinkValue) []api.Tool {
 	p.tools = tools
+	p.callIndex = 0
 	p.setInitialState(lastMessage)
 	return tools
 }
@@ -288,6 +290,11 @@ func (p *MinistralParser) Add(s string, done bool) (content string, thinking str
 		}
 	}
 
+	for i := range toolCalls {
+		toolCalls[i].Function.Index = p.callIndex
+		p.callIndex++
+	}
+
 	return contentBuilder.String(), thinkingBuilder.String(), toolCalls, nil
 }
 

model/parsers/ministral_test.go

@@ -4,6 +4,7 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/ollama/ollama/api"
 )
 
@@ -395,6 +396,54 @@ func TestMinistralParserStreaming(t *testing.T) {
 	}
 }
 
+func TestMinistralParserAssignsSequentialToolCallIndices(t *testing.T) {
+	parser := &MinistralParser{}
+	parser.Init([]api.Tool{
+		{Function: api.ToolFunction{Name: "get_weather"}},
+		{Function: api.ToolFunction{Name: "get_time"}},
+	}, nil, nil)
+
+	content, thinking, calls, err := parser.Add(
+		`[TOOL_CALLS]get_weather[ARGS]{"location":"NYC"}[TOOL_CALLS]get_time[ARGS]{"timezone":"EST"}`,
+		true,
+	)
+	if err != nil {
+		t.Fatalf("Add() error = %v", err)
+	}
+
+	if content != "" {
+		t.Fatalf("expected no content, got %q", content)
+	}
+	if thinking != "" {
+		t.Fatalf("expected no thinking, got %q", thinking)
+	}
+
+	expected := []api.ToolCall{
+		{
+			Function: api.ToolCallFunction{
+				Index: 0,
+				Name:  "get_weather",
+				Arguments: testArgs(map[string]any{
+					"location": "NYC",
+				}),
+			},
+		},
+		{
+			Function: api.ToolCallFunction{
+				Index: 1,
+				Name:  "get_time",
+				Arguments: testArgs(map[string]any{
+					"timezone": "EST",
+				}),
+			},
+		},
+	}
+
+	if diff := cmp.Diff(expected, calls, argsComparer); diff != "" {
+		t.Fatalf("tool calls mismatch (-want +got):\n%s", diff)
+	}
+}
+
 func TestMinistralParser_Errors(t *testing.T) {
 	t.Run("unknown tool returns error", func(t *testing.T) {
 		p := &MinistralParser{}

model/parsers/olmo3.go

@@ -26,8 +26,9 @@ const (
 )
 
 type Olmo3Parser struct {
-	state  olmo3ParserState
+	state     olmo3ParserState
-	buffer strings.Builder
+	buffer    strings.Builder
+	callIndex int
 }
 
 func (p *Olmo3Parser) HasToolSupport() bool {
@@ -40,6 +41,7 @@ func (p *Olmo3Parser) HasThinkingSupport() bool {
 
 func (p *Olmo3Parser) Init(tools []api.Tool, lastMessage *api.Message, thinkValue *api.ThinkValue) []api.Tool {
 	p.state = olmo3StateContent
+	p.callIndex = 0
 	return tools
 }
 
@@ -84,6 +86,11 @@ func (p *Olmo3Parser) Add(s string, done bool) (content string, thinking string,
 		}
 	}
 
+	for i := range allCalls {
+		allCalls[i].Function.Index = p.callIndex
+		p.callIndex++
+	}
+
 	return contentSb.String(), "", allCalls, nil
 }
 

model/parsers/olmo3_test.go

@@ -69,12 +69,14 @@ get_weather(location="New York")</function_calls>`,
 			expectedCalls: []api.ToolCall{
 				{
 					Function: api.ToolCallFunction{
+						Index:     0,
 						Name:      "get_weather",
 						Arguments: testArgs(map[string]any{"location": "San Francisco"}),
 					},
 				},
 				{
 					Function: api.ToolCallFunction{
+						Index:     1,
 						Name:      "get_weather",
 						Arguments: testArgs(map[string]any{"location": "New York"}),
 					},

model/parsers/qwen3vl.go

@@ -28,6 +28,7 @@ type Qwen3VLParser struct {
 	state              qwenParserState
 	buffer             strings.Builder
 	tools              []api.Tool
+	callIndex          int
 	hasThinkingSupport bool
 }
 
@@ -56,6 +57,7 @@ func (p *Qwen3VLParser) setInitialState(lastMessage *api.Message) {
 
 func (p *Qwen3VLParser) Init(tools []api.Tool, lastMessage *api.Message, thinkValue *api.ThinkValue) []api.Tool {
 	p.tools = tools
+	p.callIndex = 0
 	p.setInitialState(lastMessage)
 	return tools
 }
@@ -90,6 +92,11 @@ func (p *Qwen3VLParser) Add(s string, done bool) (content string, thinking strin
 		}
 	}
 
+	for i := range calls {
+		calls[i].Function.Index = p.callIndex
+		p.callIndex++
+	}
+
 	return contentSb.String(), thinkingSb.String(), calls, nil
 }
 

model/parsers/qwen3vl_nonthinking_test.go

@@ -4,6 +4,7 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/ollama/ollama/api"
 )
 
@@ -217,6 +218,51 @@ func TestQwen3VLNonThinkingParserStreaming(t *testing.T) {
 	}
 }
 
+func TestQwen3VLNonThinkingAssignsSequentialToolCallIndices(t *testing.T) {
+	parser := Qwen3VLParser{hasThinkingSupport: false}
+	parser.Init([]api.Tool{}, nil, nil)
+
+	content, thinking, calls, err := parser.Add(
+		`<tool_call>{"name":"first","arguments":{"a":"1"}}</tool_call><tool_call>{"name":"second","arguments":{"b":"2"}}</tool_call>`,
+		true,
+	)
+	if err != nil {
+		t.Fatalf("Add() error = %v", err)
+	}
+
+	if content != "" {
+		t.Fatalf("expected no content, got %q", content)
+	}
+	if thinking != "" {
+		t.Fatalf("expected no thinking, got %q", thinking)
+	}
+
+	expected := []api.ToolCall{
+		{
+			Function: api.ToolCallFunction{
+				Index: 0,
+				Name:  "first",
+				Arguments: testArgs(map[string]any{
+					"a": "1",
+				}),
+			},
+		},
+		{
+			Function: api.ToolCallFunction{
+				Index: 1,
+				Name:  "second",
+				Arguments: testArgs(map[string]any{
+					"b": "2",
+				}),
+			},
+		},
+	}
+
+	if diff := cmp.Diff(expected, calls, argsComparer); diff != "" {
+		t.Fatalf("tool calls mismatch (-want +got):\n%s", diff)
+	}
+}
+
 func TestQwenOldParserStreaming(t *testing.T) {
 	type step struct {
 		input      string