tools: refactor tool call parsing and enable streaming (#10415)

server/model.go

@@ -10,9 +10,6 @@ import (
 	"log/slog"
 	"net/http"
 	"os"
-	"slices"
-	"strings"
-	"text/template/parse"
 
 	"github.com/ollama/ollama/api"
 	"github.com/ollama/ollama/fs/ggml"
@@ -128,124 +125,3 @@ func detectContentType(r io.Reader) (string, error) {
 
 	return "unknown", nil
 }
-
-func parseObjects(s string) []map[string]any {
-	var objs []map[string]any
-	for offset := 0; offset < len(s); {
-		var obj map[string]any
-		decoder := json.NewDecoder(strings.NewReader(s[offset:]))
-		if err := decoder.Decode(&obj); errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {
-			break
-		} else if syntax := &(json.SyntaxError{}); errors.As(err, &syntax) {
-			// skip over any syntax errors
-			offset += int(syntax.Offset)
-		} else if unmarshalType := &(json.UnmarshalTypeError{}); errors.As(err, &unmarshalType) {
-			// skip over any unmarshalable types
-			offset += int(unmarshalType.Offset)
-		} else if err != nil {
-			return nil
-		} else {
-			offset += int(decoder.InputOffset())
-			objs = append(objs, obj)
-		}
-	}
-
-	return objs
-}
-
-// parseToolCalls attempts to parse a JSON string into a slice of ToolCalls.
-// mxyng: this only really works if the input contains tool calls in some JSON format
-func (m *Model) parseToolCalls(s string) ([]api.ToolCall, bool) {
-	// create a subtree from the node that ranges over .ToolCalls
-	tmpl := m.Template.Subtree(func(n parse.Node) bool {
-		if t, ok := n.(*parse.RangeNode); ok {
-			return slices.Contains(template.Identifiers(t.Pipe), "ToolCalls")
-		}
-
-		return false
-	})
-
-	if tmpl == nil {
-		return nil, false
-	}
-
-	var b bytes.Buffer
-	if err := tmpl.Execute(&b, map[string][]api.ToolCall{
-		"ToolCalls": {
-			{
-				Function: api.ToolCallFunction{
-					Name: "@@name@@",
-					Arguments: api.ToolCallFunctionArguments{
-						"@@argument@@": 1,
-					},
-				},
-			},
-		},
-	}); err != nil {
-		return nil, false
-	}
-
-	templateObjects := parseObjects(b.String())
-	if len(templateObjects) == 0 {
-		return nil, false
-	}
-
-	// find the keys that correspond to the name and arguments fields
-	var name, arguments string
-	for k, v := range templateObjects[0] {
-		switch v.(type) {
-		case string:
-			name = k
-		case map[string]any:
-			arguments = k
-		}
-	}
-
-	if name == "" || arguments == "" {
-		return nil, false
-	}
-
-	responseObjects := parseObjects(s)
-	if len(responseObjects) == 0 {
-		return nil, false
-	}
-
-	// collect all nested objects
-	var collect func(any) []map[string]any
-	collect = func(obj any) (all []map[string]any) {
-		switch o := obj.(type) {
-		case map[string]any:
-			all = append(all, o)
-			for _, v := range o {
-				all = append(all, collect(v)...)
-			}
-		case []any:
-			for _, v := range o {
-				all = append(all, collect(v)...)
-			}
-		}
-
-		return all
-	}
-
-	var objs []map[string]any
-	for _, p := range responseObjects {
-		objs = append(objs, collect(p)...)
-	}
-
-	var toolCalls []api.ToolCall
-	for _, kv := range objs {
-		n, nok := kv[name].(string)
-		a, aok := kv[arguments].(map[string]any)
-		if nok && aok {
-			toolCalls = append(toolCalls, api.ToolCall{
-				Function: api.ToolCallFunction{
-					Name:      n,
-					Arguments: a,
-				},
-			})
-		}
-	}
-
-	return toolCalls, len(toolCalls) > 0
-}

server/model_test.go

@@ -1,179 +0,0 @@
-package server
-
-import (
-	"bytes"
-	"encoding/json"
-	"fmt"
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/google/go-cmp/cmp"
-
-	"github.com/ollama/ollama/api"
-	"github.com/ollama/ollama/template"
-)
-
-func readFile(t *testing.T, base, name string) *bytes.Buffer {
-	t.Helper()
-
-	bts, err := os.ReadFile(filepath.Join(base, name))
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	return bytes.NewBuffer(bts)
-}
-
-func TestExecuteWithTools(t *testing.T) {
-	p := filepath.Join("testdata", "tools")
-	cases := []struct {
-		model  string
-		output string
-		ok     bool
-	}{
-		{"mistral", `[TOOL_CALLS]  [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`, true},
-		{"mistral", `[TOOL_CALLS]  [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]
-
-The temperature in San Francisco, CA is 70°F and in Toronto, Canada is 20°C.`, true},
-		{"mistral", `[TOOL_CALLS]  [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"To }]`, false},
-		{"mistral", `I'm not aware of that information. However, I can suggest searching for the weather using the "get_current_weather" function:
-
-		[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`, true},
-		{"mistral", " The weather in San Francisco, CA is 70°F and in Toronto, Canada is 20°C.", false},
-		{"command-r-plus", "Action: ```json" + `
-[
-    {
-        "tool_name": "get_current_weather",
-        "parameters": {
-            "format": "fahrenheit",
-            "location": "San Francisco, CA"
-        }
-    },
-    {
-        "tool_name": "get_current_weather",
-        "parameters": {
-            "format": "celsius",
-            "location": "Toronto, Canada"
-        }
-    }
-]
-` + "```", true},
-		{"command-r-plus", " The weather in San Francisco, CA is 70°F and in Toronto, Canada is 20°C.", false},
-		{"firefunction", ` functools[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`, true},
-		{"firefunction", " The weather in San Francisco, CA is 70°F and in Toronto, Canada is 20°C.", false},
-		{"llama3-groq-tool-use", `<tool_call>
-{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}
-{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}
-</tool_call>`, true},
-		{"xlam", `{"tool_calls": [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]}`, true},
-		{"nemotron", `<toolcall>{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]} </toolcall>`, true},
-	}
-
-	var tools []api.Tool
-	if err := json.Unmarshal(readFile(t, p, "tools.json").Bytes(), &tools); err != nil {
-		t.Fatal(err)
-	}
-
-	var messages []api.Message
-	if err := json.Unmarshal(readFile(t, p, "messages.json").Bytes(), &messages); err != nil {
-		t.Fatal(err)
-	}
-
-	calls := []api.ToolCall{
-		{
-			Function: api.ToolCallFunction{
-				Name: "get_current_weather",
-				Arguments: api.ToolCallFunctionArguments{
-					"format":   "fahrenheit",
-					"location": "San Francisco, CA",
-				},
-			},
-		},
-		{
-			Function: api.ToolCallFunction{
-				Name: "get_current_weather",
-				Arguments: api.ToolCallFunctionArguments{
-					"format":   "celsius",
-					"location": "Toronto, Canada",
-				},
-			},
-		},
-	}
-
-	for _, tt := range cases {
-		t.Run(tt.model, func(t *testing.T) {
-			tmpl, err := template.Parse(readFile(t, p, fmt.Sprintf("%s.gotmpl", tt.model)).String())
-			if err != nil {
-				t.Fatal(err)
-			}
-
-			t.Run("template", func(t *testing.T) {
-				var actual bytes.Buffer
-				if err := tmpl.Execute(&actual, template.Values{Tools: tools, Messages: messages}); err != nil {
-					t.Fatal(err)
-				}
-
-				if diff := cmp.Diff(actual.String(), readFile(t, p, fmt.Sprintf("%s.out", tt.model)).String()); diff != "" {
-					t.Errorf("mismatch (-got +want):\n%s", diff)
-				}
-			})
-
-			t.Run("parse", func(t *testing.T) {
-				m := &Model{Template: tmpl}
-				actual, ok := m.parseToolCalls(tt.output)
-				if ok != tt.ok {
-					t.Fatalf("expected %t, got %t", tt.ok, ok)
-				}
-
-				if tt.ok {
-					if diff := cmp.Diff(actual, calls); diff != "" {
-						t.Errorf("mismatch (-got +want):\n%s", diff)
-					}
-				}
-			})
-		})
-	}
-}
-
-func TestParseObjects(t *testing.T) {
-	tests := []struct {
-		input string
-		want  []map[string]any
-	}{
-		{
-			input: `[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
-			want: []map[string]any{
-				{"name": "get_current_weather", "arguments": map[string]any{"format": "fahrenheit", "location": "San Francisco, CA"}},
-				{"name": "get_current_weather", "arguments": map[string]any{"format": "celsius", "location": "Toronto, Canada"}},
-			},
-		},
-		{
-			input: `<toolcall>{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </toolcall>`,
-			want: []map[string]any{
-				{"name": "get_current_weather", "arguments": map[string]any{"format": "fahrenheit", "location": "San Francisco, CA"}},
-			},
-		},
-		{
-			input: `<toolcall>{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </toolcall> <toolcall>{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, ON"}} </toolcall>`,
-			want: []map[string]any{
-				{"name": "get_current_weather", "arguments": map[string]any{"format": "fahrenheit", "location": "San Francisco, CA"}},
-				{"name": "get_current_weather", "arguments": map[string]any{"format": "celsius", "location": "Toronto, ON"}},
-			},
-		},
-		{
-			input: `{"name": "get_current_weather", "arguments": `,
-			want:  nil,
-		},
-	}
-
-	for _, tc := range tests {
-		t.Run(tc.input, func(t *testing.T) {
-			got := parseObjects(tc.input)
-
-			if diff := cmp.Diff(got, tc.want); diff != "" {
-				t.Errorf("mismatch (-got +want):\n%s", diff)
-			}
-		})
-	}
-}

server/routes.go

@@ -38,6 +38,7 @@ import (
 	"github.com/ollama/ollama/server/internal/client/ollama"
 	"github.com/ollama/ollama/server/internal/registry"
 	"github.com/ollama/ollama/template"
+	"github.com/ollama/ollama/tools"
 	"github.com/ollama/ollama/types/errtypes"
 	"github.com/ollama/ollama/types/model"
 	"github.com/ollama/ollama/version"
@@ -1482,11 +1483,20 @@ func (s *Server) ChatHandler(c *gin.Context) {
 		return
 	}
 
+	var toolParser *tools.Parser
+	if len(req.Tools) > 0 {
+		toolParser, err = tools.NewParser(m.Template.Template)
+		if err != nil {
+			slog.Error("failed to create tool parser", "error", err)
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+	}
+
 	ch := make(chan any)
 	go func() {
 		defer close(ch)
-		var sb strings.Builder
-		var toolCallIndex int = 0
+
 		if err := r.Completion(c.Request.Context(), llm.CompletionRequest{
 			Prompt:  prompt,
 			Images:  images,
@@ -1512,37 +1522,21 @@ func (s *Server) ChatHandler(c *gin.Context) {
 				res.LoadDuration = checkpointLoaded.Sub(checkpointStart)
 			}
 
-			// TODO: tool call checking and filtering should be moved outside of this callback once streaming
-			// however this was a simple change for now without reworking streaming logic of this (and other)
-			// handlers
-			if req.Stream != nil && !*req.Stream || len(req.Tools) == 0 {
-				ch <- res
-				return
-			}
-
-			// Streaming tool calls:
-			// If tools are recognized, use a flag to track the sending of a tool downstream
-			// This ensures that content is cleared from the message on the last chunk sent
-			sb.WriteString(r.Content)
-			if toolCalls, ok := m.parseToolCalls(sb.String()); ok {
-				res.Message.ToolCalls = toolCalls
-				for i := range toolCalls {
-					toolCalls[i].Function.Index = toolCallIndex
-					toolCallIndex++
+			if len(req.Tools) > 0 {
+				toolCalls, content := toolParser.Add(r.Content)
+				if len(content) > 0 {
+					res.Message.Content = content
+				} else if len(toolCalls) > 0 {
+					res.Message.ToolCalls = toolCalls
+					res.Message.Content = ""
+				} else {
+					if r.Done {
+						ch <- res
+					}
+					return
 				}
-				res.Message.Content = ""
-				sb.Reset()
-				ch <- res
-				return
-			}
-
-			if r.Done {
-				// Send any remaining content if no tool calls were detected
-				if toolCallIndex == 0 {
-					res.Message.Content = sb.String()
-				}
-				ch <- res
 			}
+			ch <- res
 		}); err != nil {
 			ch <- gin.H{"error": err.Error()}
 		}
@@ -1551,11 +1545,15 @@ func (s *Server) ChatHandler(c *gin.Context) {
 	if req.Stream != nil && !*req.Stream {
 		var resp api.ChatResponse
 		var sb strings.Builder
+		var toolCalls []api.ToolCall
 		for rr := range ch {
 			switch t := rr.(type) {
 			case api.ChatResponse:
 				sb.WriteString(t.Message.Content)
 				resp = t
+				if len(req.Tools) > 0 {
+					toolCalls = append(toolCalls, t.Message.ToolCalls...)
+				}
 			case gin.H:
 				msg, ok := t["error"].(string)
 				if !ok {
@@ -1571,12 +1569,8 @@ func (s *Server) ChatHandler(c *gin.Context) {
 		}
 
 		resp.Message.Content = sb.String()
-
-		if len(req.Tools) > 0 {
-			if toolCalls, ok := m.parseToolCalls(sb.String()); ok {
-				resp.Message.ToolCalls = toolCalls
-				resp.Message.Content = ""
-			}
+		if len(toolCalls) > 0 {
+			resp.Message.ToolCalls = toolCalls
 		}
 
 		c.JSON(http.StatusOK, resp)

tools/testdata/llama3.2.gotmpl

@@ -0,0 +1,44 @@
+<|start_header_id|>system<|end_header_id|>
+
+Cutting Knowledge Date: December 2023
+
+{{ if .System }}{{ .System }}
+{{- end }}
+{{- if .Tools }}When you receive a tool call response, use the output to format an answer to the orginal user question.
+
+You are a helpful assistant with tool calling capabilities.
+{{- end }}<|eot_id|>
+{{- range $i, $_ := .Messages }}
+{{- $last := eq (len (slice $.Messages $i)) 1 }}
+{{- if eq .Role "user" }}<|start_header_id|>user<|end_header_id|>
+{{- if and $.Tools $last }}
+
+Given the following functions, please respond with a JSON for a function call with its proper arguments that best answers the given prompt.
+
+Respond in the format {"name": function name, "parameters": dictionary of argument name and its value}. Do not use variables.
+
+{{ range $.Tools }}
+{{- . }}
+{{ end }}
+{{ .Content }}<|eot_id|>
+{{- else }}
+
+{{ .Content }}<|eot_id|>
+{{- end }}{{ if $last }}<|start_header_id|>assistant<|end_header_id|>
+
+{{ end }}
+{{- else if eq .Role "assistant" }}<|start_header_id|>assistant<|end_header_id|>
+{{- if .ToolCalls }}
+{{ range .ToolCalls }}
+{"name": "{{ .Function.Name }}", "parameters": {{ .Function.Arguments }}}{{ end }}
+{{- else }}
+
+{{ .Content }}
+{{- end }}{{ if not $last }}<|eot_id|>{{ end }}
+{{- else if eq .Role "tool" }}<|start_header_id|>ipython<|end_header_id|>
+
+{{ .Content }}<|eot_id|>{{ if $last }}<|start_header_id|>assistant<|end_header_id|>
+
+{{ end }}
+{{- end }}
+{{- end }}

tools/testdata/llama3.2.out

@@ -0,0 +1,24 @@
+<|start_header_id|>system<|end_header_id|>
+
+Cutting Knowledge Date: December 2023
+
+You are a knowledgeable assistant. You can answer questions and perform tasks.When you receive a tool call response, use the output to format an answer to the orginal user question.
+
+You are a helpful assistant with tool calling capabilities.<|eot_id|><|start_header_id|>user<|end_header_id|>
+
+What's the weather like today in Paris?<|eot_id|><|start_header_id|>assistant<|end_header_id|>
+
+{"name": "get_current_weather", "parameters": {"format":"celsius","location":"Paris, France"}}<|eot_id|><|start_header_id|>ipython<|end_header_id|>
+
+22<|eot_id|><|start_header_id|>assistant<|end_header_id|>
+
+The current temperature in Paris, France is 22 degrees Celsius.<|eot_id|><|start_header_id|>user<|end_header_id|>
+
+Given the following functions, please respond with a JSON for a function call with its proper arguments that best answers the given prompt.
+
+Respond in the format {"name": function name, "parameters": dictionary of argument name and its value}. Do not use variables.
+
+{"type":"function","function":{"name":"get_current_weather","description":"Get the current weather","parameters":{"type":"object","required":["location","format"],"properties":{"format":{"type":"string","description":"The temperature unit to use. Infer this from the user's location.","enum":["celsius","fahrenheit"]},"location":{"type":"string","description":"The city and state, e.g. San Francisco, CA"}}}}}
+
+What's the weather like today in San Francisco and Toronto?<|eot_id|><|start_header_id|>assistant<|end_header_id|>
+

tools/testdata/qwen2.5.gotmpl

@@ -0,0 +1,51 @@
+{{- if .Suffix }}<|fim_prefix|>{{ .Prompt }}<|fim_suffix|>{{ .Suffix }}<|fim_middle|>
+{{- else if .Messages }}
+{{- if or .System .Tools }}<|im_start|>system
+{{- if .System }}
+{{ .System }}
+{{- end }}
+{{- if .Tools }}
+
+# Tools
+
+You may call one or more functions to assist with the user query.
+
+You are provided with function signatures within <tools></tools> XML tags:
+<tools>
+{{- range .Tools }}
+{"type": "function", "function": {{ .Function }}}
+{{- end }}
+</tools>
+
+For each function call, return a json object with function name and arguments within <tool_call></tool_call> XML tags:
+<tool_call>
+{"name": <function-name>, "arguments": <args-json-object>}
+</tool_call>
+{{- end }}<|im_end|>
+{{ end }}
+{{- range $i, $_ := .Messages }}
+{{- $last := eq (len (slice $.Messages $i)) 1 -}}
+{{- if eq .Role "user" }}<|im_start|>user
+{{ .Content }}<|im_end|>
+{{ else if eq .Role "assistant" }}<|im_start|>assistant
+{{ if .Content }}{{ .Content }}
+{{- else if .ToolCalls }}<tool_call>
+{{ range .ToolCalls }}{"name": "{{ .Function.Name }}", "arguments": {{ .Function.Arguments }}}
+{{ end }}</tool_call>
+{{- end }}{{ if not $last }}<|im_end|>
+{{ end }}
+{{- else if eq .Role "tool" }}<|im_start|>user
+<tool_response>
+{{ .Content }}
+</tool_response><|im_end|>
+{{ end }}
+{{- if and (ne .Role "assistant") $last }}<|im_start|>assistant
+{{ end }}
+{{- end }}
+{{- else }}
+{{- if .System }}<|im_start|>system
+{{ .System }}<|im_end|>
+{{ end }}{{ if .Prompt }}<|im_start|>user
+{{ .Prompt }}<|im_end|>
+{{ end }}<|im_start|>assistant
+{{ end }}{{ .Response }}{{ if .Response }}<|im_end|>{{ end }}

tools/testdata/qwen2.5.out

@@ -0,0 +1,31 @@
+<|im_start|>system
+You are a knowledgeable assistant. You can answer questions and perform tasks.
+
+# Tools
+
+You may call one or more functions to assist with the user query.
+
+You are provided with function signatures within <tools></tools> XML tags:
+<tools>
+{"type": "function", "function": {"name":"get_current_weather","description":"Get the current weather","parameters":{"type":"object","required":["location","format"],"properties":{"format":{"type":"string","description":"The temperature unit to use. Infer this from the user's location.","enum":["celsius","fahrenheit"]},"location":{"type":"string","description":"The city and state, e.g. San Francisco, CA"}}}}}
+</tools>
+
+For each function call, return a json object with function name and arguments within <tool_call></tool_call> XML tags:
+<tool_call>
+{"name": <function-name>, "arguments": <args-json-object>}
+</tool_call><|im_end|>
+<|im_start|>user
+What's the weather like today in Paris?<|im_end|>
+<|im_start|>assistant
+<tool_call>
+{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Paris, France"}}
+</tool_call><|im_end|>
+<|im_start|>user
+<tool_response>
+22
+</tool_response><|im_end|>
+<|im_start|>assistant
+The current temperature in Paris, France is 22 degrees Celsius.<|im_end|>
+<|im_start|>user
+What's the weather like today in San Francisco and Toronto?<|im_end|>
+<|im_start|>assistant

tools/testdata/qwen3.gotmpl

@@ -0,0 +1,50 @@
+{{- if .Messages }}
+{{- if or .System .Tools }}<|im_start|>system
+{{- if .System }}
+{{ .System }}
+{{- end }}
+{{- if .Tools }}
+
+# Tools
+
+You may call one or more functions to assist with the user query.
+
+You are provided with function signatures within <tools></tools> XML tags:
+<tools>
+{{- range .Tools }}
+{"type": "function", "function": {{ .Function }}}
+{{- end }}
+</tools>
+
+For each function call, return a json object with function name and arguments within <tool_call></tool_call> XML tags:
+<tool_call>
+{"name": <function-name>, "arguments": <args-json-object>}
+</tool_call>
+{{- end }}<|im_end|>
+{{ end }}
+{{- range $i, $_ := .Messages }}
+{{- $last := eq (len (slice $.Messages $i)) 1 -}}
+{{- if eq .Role "user" }}<|im_start|>user
+{{ .Content }}<|im_end|>
+{{ else if eq .Role "assistant" }}<|im_start|>assistant
+{{ if .Content }}{{ .Content }}
+{{- else if .ToolCalls }}<tool_call>
+{{ range .ToolCalls }}{"name": "{{ .Function.Name }}", "arguments": {{ .Function.Arguments }}}
+{{ end }}</tool_call>
+{{- end }}{{ if not $last }}<|im_end|>
+{{ end }}
+{{- else if eq .Role "tool" }}<|im_start|>user
+<tool_response>
+{{ .Content }}
+</tool_response><|im_end|>
+{{ end }}
+{{- if and (ne .Role "assistant") $last }}<|im_start|>assistant
+{{ end }}
+{{- end }}
+{{- else }}
+{{- if .System }}<|im_start|>system
+{{ .System }}<|im_end|>
+{{ end }}{{ if .Prompt }}<|im_start|>user
+{{ .Prompt }}<|im_end|>
+{{ end }}<|im_start|>assistant
+{{ end }}{{ .Response }}{{ if .Response }}<|im_end|>{{ end }}

tools/testdata/qwen3.out

@@ -0,0 +1,31 @@
+<|im_start|>system
+You are a knowledgeable assistant. You can answer questions and perform tasks.
+
+# Tools
+
+You may call one or more functions to assist with the user query.
+
+You are provided with function signatures within <tools></tools> XML tags:
+<tools>
+{"type": "function", "function": {"name":"get_current_weather","description":"Get the current weather","parameters":{"type":"object","required":["location","format"],"properties":{"format":{"type":"string","description":"The temperature unit to use. Infer this from the user's location.","enum":["celsius","fahrenheit"]},"location":{"type":"string","description":"The city and state, e.g. San Francisco, CA"}}}}}
+</tools>
+
+For each function call, return a json object with function name and arguments within <tool_call></tool_call> XML tags:
+<tool_call>
+{"name": <function-name>, "arguments": <args-json-object>}
+</tool_call><|im_end|>
+<|im_start|>user
+What's the weather like today in Paris?<|im_end|>
+<|im_start|>assistant
+<tool_call>
+{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Paris, France"}}
+</tool_call><|im_end|>
+<|im_start|>user
+<tool_response>
+22
+</tool_response><|im_end|>
+<|im_start|>assistant
+The current temperature in Paris, France is 22 degrees Celsius.<|im_end|>
+<|im_start|>user
+What's the weather like today in San Francisco and Toronto?<|im_end|>
+<|im_start|>assistant

tools/tools.go

@@ -0,0 +1,271 @@
+package tools
+
+import (
+	"encoding/json"
+	"errors"
+	"log/slog"
+	"strings"
+	gotmpl "text/template"
+
+	"github.com/ollama/ollama/api"
+	"github.com/ollama/ollama/template"
+)
+
+var (
+	errInvalidToolCall = errors.New("invalid tool call format")
+	errAccumulateMore  = errors.New("need to accumulate more content")
+)
+
+type Parser struct {
+	parseLeadingJSON bool
+	prefix           string
+	prefixFound      bool
+	tmpl             gotmpl.Template
+	sb               strings.Builder
+	index            int
+	name             string
+	arguments        string
+	done             bool
+}
+
+// parseJSONToolCalls attempts to parse a JSON string into a slice of ToolCalls.
+//
+// Parameters:
+//   - s: The string to parse
+//   - name: The field name from template that identifies the tool call name
+//   - arguments: The field name from template that identifies the tool call arguments
+//
+// Returns:
+//   - []api.ToolCall: The parsed tool calls if successful
+//   - error: ErrAccumulateMore if braces unbalanced, ErrInvalidToolCall if invalid, or nil if successful
+func parseJSONToolCalls(s string, name, arguments string, prefix string) ([]api.ToolCall, error) {
+	// Check for balanced braces before attempting to parse
+	braceCount := 0
+	squareCount := 0
+	startIndex := -1
+	var rawToolCalls []string
+	s = strings.TrimSpace(s)
+
+	// Only track these if we don't have a prefix as it will be cut off from the prefix. Also track in the parseLeadingJSON case.
+	trackSquareBrackets := prefix == "" || !strings.HasSuffix(prefix, "[") || strings.HasPrefix(s, "[")
+	for i, c := range s {
+		switch c {
+		case '{':
+			braceCount++
+			if startIndex == -1 {
+				startIndex = i
+			}
+		case '}':
+			braceCount--
+			if braceCount == 0 {
+				rawToolCalls = append(rawToolCalls, s[startIndex:i+1])
+				startIndex = -1
+			}
+		case '[':
+			if trackSquareBrackets {
+				squareCount++
+			}
+		case ']':
+			if trackSquareBrackets {
+				squareCount--
+			}
+		}
+
+		// Negative means we have an extra closing brace/bracket
+		if braceCount < 0 || squareCount < 0 {
+			return nil, errInvalidToolCall
+		}
+	}
+
+	// If braces/brackets aren't balanced, need more input
+	if braceCount > 0 || squareCount > 0 {
+		return nil, errAccumulateMore
+	}
+
+	t := strings.TrimSpace(s)
+	if len(t) == 0 {
+		return nil, errAccumulateMore
+	}
+	// If the input is a single square bracket, it's not a valid tool call
+	if t[0] == '[' && len(t) == 1 {
+		return nil, errAccumulateMore
+	}
+
+	// Attempt full unmarshal of the JSON
+	var toolCalls []api.ToolCall
+	for _, rawToolCall := range rawToolCalls {
+		var resp map[string]any
+		if err := json.Unmarshal([]byte(rawToolCall), &resp); err != nil {
+			continue
+		}
+
+		// Collect nested objects that could contain tool calls
+		objs := collect(resp)
+		if len(objs) == 0 {
+			continue
+		}
+
+		// Extract tool calls from objects
+		for _, kv := range objs {
+			n, nok := kv[name].(string)
+			a, aok := kv[arguments].(map[string]any)
+			if nok && aok {
+				toolCalls = append(toolCalls, api.ToolCall{
+					Function: api.ToolCallFunction{
+						Name:      n,
+						Arguments: a,
+					},
+				})
+			} else {
+				slog.Debug("No valid tool call found in object.", "object", kv)
+			}
+		}
+	}
+
+	// Valid JSON, no tool calls found
+	if len(toolCalls) == 0 {
+		slog.Debug("No valid tool calls found in any raw tool calls.", "rawToolCalls", rawToolCalls)
+		return nil, errInvalidToolCall
+	}
+
+	return toolCalls, nil
+}
+
+// checkPrefix processes a string to find and handle a prefix pattern.
+//
+// Returns:
+//   - The processed string with prefix removed if found
+//   - error: ErrAccumulateMore if prefix is incomplete, or nil if successful
+func (p *Parser) checkPrefix(s string) (string, error) {
+	original := s
+	if strings.ContainsRune(s, '\n') {
+		s = strings.ReplaceAll(s, "\n", " ")
+	}
+
+	if s == "" || p.prefix == "" {
+		return s, nil
+	}
+
+	// Check for prefix at start of string
+	if cut, hasPrefix := strings.CutPrefix(s, p.prefix); hasPrefix {
+		// Found prefix at start - accumulate for potential tool
+		p.prefixFound = true
+		return cut, nil
+	}
+
+	// Check if prefix overlaps end of string
+	if idx := suffixOverlap(s, p.prefix); idx != -1 {
+		// Return everything except overlapping portion
+		p.sb.Reset()
+		p.sb.WriteString(s[idx:])
+		return original[:idx], errAccumulateMore
+	}
+
+	// Check if prefix appears in middle of string
+	if idx := strings.Index(s, p.prefix); idx != -1 {
+		// Save remainder starting at prefix for next pass
+		p.sb.Reset()
+		p.sb.WriteString(strings.TrimSpace(s[idx:]))
+		// Return everything before prefix
+		return original[:idx], errAccumulateMore
+	}
+
+	// No partial prefix found
+	return s, nil
+}
+
+// Add processes a string input to parse tool calls and content.
+// It handles prefix detection and JSON parsing to extract tool calls.
+//
+// Returns:
+//   - tools: Any parsed tool calls
+//   - content: Non-tool call content
+func (p *Parser) Add(s string) (tools []api.ToolCall, content string) {
+	if strings.TrimSpace(s) == "" {
+		return nil, s
+	}
+	if p.done {
+		if p.index == 0 {
+			// Return original string if no tool calls found at start
+			return nil, s
+		}
+		// Return empty if no tool calls found after start
+		return nil, ""
+	}
+	p.sb.WriteString(s)
+	s = p.sb.String()
+
+	// Check for prefix pattern in input
+	s, err := p.checkPrefix(s)
+	if err != nil {
+		// Need more input to complete prefix
+		return nil, s
+	}
+
+	// Exit if prefix exists in template, greedy parsing is off, and prefix not found
+	if !p.parseLeadingJSON && !p.prefixFound {
+		p.sb.Reset()
+		return nil, s
+	}
+
+	toolCalls, err := parseJSONToolCalls(s, p.name, p.arguments, p.prefix)
+	if err != nil {
+		if errors.Is(err, errAccumulateMore) {
+			return nil, ""
+		}
+		p.sb.Reset()
+		// Do not try parsing leading JSON if JSON not found
+		p.parseLeadingJSON = false
+		if p.prefix == "" {
+			p.done = true
+		}
+		if p.index != 0 && p.prefix == "" {
+			return nil, ""
+		}
+		if p.prefixFound {
+			// Drop tokens since prefix was found
+			return nil, ""
+		}
+		return nil, s
+	}
+
+	for _, tc := range toolCalls {
+		tc.Function.Index = p.index
+		p.index++
+	}
+
+	p.sb.Reset()
+	return toolCalls, ""
+}
+
+// NewParser creates a new tool call parser from a template. It extracts the tool call format,
+// prefix, and field names from the template to use for parsing tool calls from model output.
+//
+// Returns an error if the template does not contain valid tool call formatting.
+func NewParser(templateToProcess *gotmpl.Template) (*Parser, error) {
+	parsed, err := template.Parse(templateToProcess.Root.String())
+	if err != nil {
+		return nil, err
+	}
+
+	tt, err := toolTemplate(parsed)
+	if err != nil {
+		return nil, err
+	}
+
+	tp := toolPrefix(templateToProcess)
+
+	name, arguments, err := extractToolArgs(tt)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Parser{
+		tmpl:             *tt,
+		sb:               strings.Builder{},
+		prefix:           tp,
+		parseLeadingJSON: true,
+		name:             name,
+		arguments:        arguments,
+	}, nil
+}

tools/tools_test.go

@@ -0,0 +1,644 @@
+package tools
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+
+	"github.com/ollama/ollama/api"
+	"github.com/ollama/ollama/template"
+)
+
+func readFile(t *testing.T, base, name string) *bytes.Buffer {
+	t.Helper()
+
+	bts, err := os.ReadFile(filepath.Join(base, name))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return bytes.NewBuffer(bts)
+}
+
+func TestParseJSONToolCalls(t *testing.T) {
+	tests := []struct {
+		name          string
+		input         string
+		nameField     string
+		argsField     string
+		wantToolCalls []api.ToolCall
+		wantErr       error
+		prefix        string
+	}{
+		{
+			name:      "valid single tool call",
+			input:     `{"name": "test_tool", "arguments": {"arg1": "value1"}}`,
+			nameField: "name",
+			argsField: "arguments",
+			wantToolCalls: []api.ToolCall{
+				{
+					Function: api.ToolCallFunction{
+						Name: "test_tool",
+						Arguments: map[string]any{
+							"arg1": "value1",
+						},
+					},
+				},
+			},
+			wantErr: nil,
+			prefix:  "",
+		},
+		{
+			name:          "incomplete JSON",
+			input:         `{"name": "test_tool", "arguments": {"arg1": `,
+			nameField:     "name",
+			argsField:     "arguments",
+			wantToolCalls: nil,
+			wantErr:       errAccumulateMore,
+			prefix:        "",
+		},
+		{
+			name:          "invalid JSON",
+			input:         `not json at all`,
+			nameField:     "name",
+			argsField:     "arguments",
+			wantToolCalls: nil,
+			wantErr:       errInvalidToolCall,
+			prefix:        "",
+		},
+		{
+			name:          "missing required fields",
+			input:         `{"other": "field"}`,
+			nameField:     "name",
+			argsField:     "arguments",
+			wantToolCalls: nil,
+			wantErr:       errInvalidToolCall,
+			prefix:        "",
+		},
+		{
+			name: "multiple tool calls in array",
+			input: `[
+				{"name": "tool1", "arguments": {"arg1": 1}},
+				{"name": "tool2", "arguments": {"arg2": "value"}}
+			]`,
+			nameField: "name",
+			argsField: "arguments",
+			wantToolCalls: []api.ToolCall{
+				{
+					Function: api.ToolCallFunction{
+						Name: "tool1",
+						Arguments: map[string]any{
+							"arg1": float64(1),
+						},
+					},
+				},
+				{
+					Function: api.ToolCallFunction{
+						Name: "tool2",
+						Arguments: map[string]any{
+							"arg2": "value",
+						},
+					},
+				},
+			},
+			wantErr: nil,
+			prefix:  "",
+		},
+		{
+			name: "multiple tool calls without array",
+			input: `
+				{"name": "tool1", "arguments": {"arg1": 1}},
+				{"name": "tool2", "arguments": {"arg2": "value"}}
+			`,
+			nameField: "name",
+			argsField: "arguments",
+			wantToolCalls: []api.ToolCall{
+				{
+					Function: api.ToolCallFunction{
+						Name: "tool1",
+						Arguments: map[string]any{
+							"arg1": float64(1),
+						},
+					},
+				},
+				{
+					Function: api.ToolCallFunction{
+						Name: "tool2",
+						Arguments: map[string]any{
+							"arg2": "value",
+						},
+					},
+				},
+			},
+			wantErr: nil,
+			prefix:  "",
+		},
+		{
+			name: "multiple tool calls with text after",
+			input: `
+				{"name": "tool1", "arguments": {"arg1": 1}} text
+				{"name": "tool2", "arguments": {"arg2": "value"}} text
+			`,
+			nameField: "name",
+			argsField: "arguments",
+			wantToolCalls: []api.ToolCall{
+				{
+					Function: api.ToolCallFunction{
+						Name: "tool1",
+						Arguments: map[string]any{
+							"arg1": float64(1),
+						},
+					},
+				},
+				{
+					Function: api.ToolCallFunction{
+						Name: "tool2",
+						Arguments: map[string]any{
+							"arg2": "value",
+						},
+					},
+				},
+			},
+			wantErr: nil,
+			prefix:  "",
+		},
+		{
+			name: "second tool call in array",
+			input: `
+				, {"name": "tool2", "arguments": {"arg2": "value"}}
+			`,
+			nameField: "name",
+			argsField: "arguments",
+			wantToolCalls: []api.ToolCall{
+				{
+					Function: api.ToolCallFunction{
+						Name: "tool2",
+						Arguments: map[string]any{
+							"arg2": "value",
+						},
+					},
+				},
+			},
+			wantErr: nil,
+			prefix:  "",
+		},
+		// a bad JSON would not return any tool calls or content as it would always accumulate more
+		{
+			name:          "unbalanced square brackets",
+			input:         `[{"name": "tool1", "arguments": {"arg1": [1, 2}]`,
+			nameField:     "name",
+			argsField:     "arguments",
+			wantToolCalls: nil,
+			wantErr:       errAccumulateMore,
+			prefix:        "",
+		},
+		{
+			name:          "incomplete square brackets",
+			input:         `[{"name": "tool1", "arguments": {"arg1": [1, 2, 3`,
+			nameField:     "name",
+			argsField:     "arguments",
+			wantToolCalls: nil,
+			wantErr:       errAccumulateMore,
+			prefix:        "",
+		},
+		{
+			name:      "nested arrays in arguments",
+			input:     `{"name": "tool1", "arguments": {"arg1": [1, 2, ["nested", "array"]]}}`,
+			nameField: "name",
+			argsField: "arguments",
+			wantToolCalls: []api.ToolCall{
+				{
+					Function: api.ToolCallFunction{
+						Name: "tool1",
+						Arguments: map[string]any{
+							"arg1": []any{float64(1), float64(2), []any{"nested", "array"}},
+						},
+					},
+				},
+			},
+			wantErr: nil,
+			prefix:  "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotCalls, err := parseJSONToolCalls(tt.input, tt.nameField, tt.argsField, tt.prefix)
+
+			if err != tt.wantErr {
+				t.Errorf("parseJSONToolCalls() error = %v, want %v", err, tt.wantErr)
+			}
+
+			if len(gotCalls) != 0 && tt.wantErr != nil {
+				t.Errorf("parseJSONToolCalls() valid = %v, want %v", len(gotCalls) == 0, tt.wantErr == nil)
+			}
+
+			if diff := cmp.Diff(gotCalls, tt.wantToolCalls); diff != "" {
+				t.Errorf("parseJSONToolCalls() tool calls mismatch (-got +want):\n%s", diff)
+			}
+		})
+	}
+}
+
+func TestParseToolCalls(t *testing.T) {
+	p := filepath.Join("testdata")
+	t1 := api.ToolCall{
+		Function: api.ToolCallFunction{
+			Name: "get_current_weather",
+			Arguments: api.ToolCallFunctionArguments{
+				"format":   "fahrenheit",
+				"location": "San Francisco, CA",
+			},
+		},
+	}
+	t2 := api.ToolCall{
+		Function: api.ToolCallFunction{
+			Name: "get_current_weather",
+			Arguments: api.ToolCallFunctionArguments{
+				"format":   "celsius",
+				"location": "Toronto, Canada",
+			},
+		},
+	}
+
+	cases := []struct {
+		name             string
+		model            string
+		output           string
+		expectedToolCall []api.ToolCall
+		expectedTokens   string
+	}{
+		{
+			name:             "mistral malformed json with tool calls prefix",
+			model:            "mistral",
+			output:           `[TOOL_CALLS]  [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_curren}]`,
+			expectedToolCall: []api.ToolCall{t1},
+			expectedTokens:   "",
+		},
+		{
+			name:             "mistral multiple tool calls without prefix",
+			model:            "mistral",
+			output:           `[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}} ]`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:  "mistral tool calls with text between no prefix",
+			model: "mistral",
+			output: `[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}] 
+			model outputs more tokens here and then [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   `model outputs more tokens here and then [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+		},
+		{
+			name:             "mistral valid json with tool calls prefix",
+			model:            "mistral",
+			output:           `[TOOL_CALLS]  [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:  "mistral multiple tool calls with text between and prefix",
+			model: "mistral",
+			output: `[TOOL_CALLS]  [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]
+			model outputs more tokens here and then [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{t1, t2, t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "mistral incomplete json with tool calls prefix",
+			model:            "mistral",
+			output:           `[TOOL_CALLS]  [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, `,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   "",
+		},
+		{
+			name:  "mistral invalid tool call with explanatory text no prefix",
+			model: "mistral",
+			output: `I'm not aware of that information. However, I can suggest searching for the weather using the "get_current_weather" function:
+
+		[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `I'm not aware of that information. However, I can suggest searching for the weather using the "get_current_weather" function: [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+		},
+		{
+			name:             "mistral tool calls without prefix",
+			model:            "mistral",
+			output:           `[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:  "command r plus tool calls with json block format",
+			model: "command-r-plus",
+			output: "Action: ```json" + `
+		[
+		    {
+		        "tool_name": "get_current_weather",
+		        "parameters": {
+		            "format": "fahrenheit",
+		            "location": "San Francisco, CA"
+		        }
+		    },
+		    {
+		        "tool_name": "get_current_weather",
+		        "parameters": {
+		            "format": "celsius",
+		            "location": "Toronto, Canada"
+		        }
+		    }
+		]
+		` + "```",
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "firefunction tool calls with functools prefix",
+			model:            "firefunction",
+			output:           ` functools[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:  "llama3 groq single tool call with xml tags",
+			model: "llama3-groq-tool-use",
+			output: `<tool_call>
+		{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}
+		</tool_call>`,
+			expectedToolCall: []api.ToolCall{t1},
+			expectedTokens:   "",
+		},
+		{
+			name:             "xlam tool calls with wrapper object",
+			model:            "xlam",
+			output:           `{"tool_calls": [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}},{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]}`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "qwen2.5 single tool call with prefix",
+			model:            "qwen2.5",
+			output:           `<tool_call>{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}</tool_call>`,
+			expectedToolCall: []api.ToolCall{t1},
+			expectedTokens:   "",
+		},
+		{
+			name:             "qwen2.5 multiple tool calls with and without prefix",
+			model:            "qwen2.5",
+			output:           `{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} <tool_call>{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}</tool_call> <tool_call>{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}</tool_call>`,
+			expectedToolCall: []api.ToolCall{t1, t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "qwen2.5 plain text response no tool calls",
+			model:            "qwen2.5",
+			output:           "The weather in San Francisco, CA is 70°F and in Toronto, Canada is 20°C.",
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   "The weather in San Francisco, CA is 70°F and in Toronto, Canada is 20°C.",
+		},
+		{
+			name:             "qwen2.5 tool calls with trailing text",
+			model:            "qwen2.5",
+			output:           `[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}, {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}] some tokens after call`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "some tokens after call",
+		},
+		{
+			name:             "qwen2.5 tool calls with initial text",
+			model:            "qwen2.5",
+			output:           `some tokens before call [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}, {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `some tokens before call [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}, {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+		},
+		{
+			name:             "qwen2.5 tool calls with prefix and trailing text",
+			model:            "qwen2.5",
+			output:           `<tool_call> [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}, {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}] </tool_call> some tokens after call`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "qwen2.5 tool calls with prefix and initial text",
+			model:            "qwen2.5",
+			output:           `some tokens before call <tool_call> [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}, {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}] </tool_call>`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "some tokens before call",
+		},
+		{
+			name:             "qwen2.5 tool calls without and with prefix",
+			model:            "qwen2.5",
+			output:           `{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} <tool_call>{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}</tool_call>`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "qwen2.5 tool calls without and with prefix and text between",
+			model:            "qwen2.5",
+			output:           `{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} some tokens between <tool_call>{"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}</tool_call> some tokens after call`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "some tokens between",
+		},
+		{
+			name:             "qwen2.5 tool calls without prefix and invalid tool call with other tokens",
+			model:            "qwen2.5",
+			output:           `hi [{"options": "foo"}]`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `hi [{"options": "foo"}]`,
+		},
+		{
+			name:             "qwen2.5 tool calls with prefix and invalid tool call",
+			model:            "qwen2.5",
+			output:           `<tool_call> [{"options": "foo"}] </tool_call> `,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   ``,
+		},
+		{
+			name:             "qwen3 tool call with think prefix and tool prefix (sent as a single token)",
+			model:            "qwen3",
+			output:           `<think>Okay, let me think what tool we should use...</think><tool_call>{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}</tool_call>`,
+			expectedToolCall: []api.ToolCall{t1},
+			expectedTokens:   "<think>Okay, let me think what tool we should use...</think>",
+		},
+		{
+			name:             "qwen3 tool call with think prefix, tool prefix, and whitespace (sent as separate tokens)",
+			model:            "qwen3",
+			output:           `<think>Okay, let me think what tool we should use...</think> <tool_call>{ "name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </tool_call>`,
+			expectedToolCall: []api.ToolCall{t1},
+			expectedTokens:   "<think>Okay, let me think what tool we should use...</think>",
+		},
+		{
+			name:             "qwen3 empty think prefix without tool prefix and invalid tool call",
+			model:            "qwen3",
+			output:           `<think></think> {"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </tool_call>`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `<think></think> {"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </tool_call>`,
+		},
+		{
+			name:             "qwen3 empty think prefix with tool prefix and valid tool call",
+			model:            "qwen3",
+			output:           `<think></think><tool_call>{ "name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}}  </tool_call>`,
+			expectedToolCall: []api.ToolCall{t1},
+			expectedTokens:   `<think></think>`,
+		},
+		{
+			name:             "qwen3 invalid tool call with fake tool prefix (single rune suffix match)",
+			model:            "qwen3",
+			output:           `<think></think>< fakeout {"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </tool_call>`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `<think></think>< fakeout {"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </tool_call>`,
+		},
+		{
+			name:             "qwen3 invalid tool call with partial tool prefix (multiple rune suffix match)",
+			model:            "qwen3",
+			output:           `<think></think><tool_c fakeout {"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </tool_call>`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `<think></think><tool_c fakeout {"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </tool_call>`,
+		},
+		{
+			name:             "qwen3 invalid tool call with malformed tool prefix",
+			model:            "qwen3",
+			output:           `<think></think><tool_cfakeout {"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </tool_call>`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `<think></think><tool_cfakeout {"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} </tool_call>`,
+		},
+		{
+			name:             "model with prefix in template, no prefix in output",
+			model:            "qwen2.5",
+			output:           `[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "model with prefix in template, prefix in output",
+			model:            "qwen2.5",
+			output:           `<tool_call>[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]</tool_call>`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "model without prefix in template, no prefix in output",
+			model:            "llama3.2",
+			output:           `[{"name": "get_current_weather", "parameters": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "parameters": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "model without prefix in template, no prefix in output, single tool call",
+			model:            "llama3.2",
+			output:           `{"name": "get_current_weather", "parameters": {"format":"fahrenheit","location":"San Francisco, CA"}}`,
+			expectedToolCall: []api.ToolCall{t1},
+			expectedTokens:   "",
+		},
+		{
+			name:             "model without prefix in template, prefix in output",
+			model:            "llama3.2",
+			output:           `<tool_call> [{"name": "get_current_weather", "parameters": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "parameters": {"format":"celsius","location":"Toronto, Canada"}}]</tool_call>`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `<tool_call> [{"name": "get_current_weather", "parameters": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "parameters": {"format":"celsius","location":"Toronto, Canada"}}]</tool_call>`,
+		},
+		{
+			name:             "model with prefix in template, no prefix in output, tokens before",
+			model:            "qwen2.5",
+			output:           `some tokens before [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `some tokens before [{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]`,
+		},
+		{
+			name:             "model with prefix in template, prefix in output, tokens after",
+			model:            "qwen2.5",
+			output:           `<tool_call>[{"name": "get_current_weather", "arguments": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "arguments": {"format":"celsius","location":"Toronto, Canada"}}]</tool_call> some tokens after`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "model without prefix in template, no prefix in output, tokens after",
+			model:            "llama3.2",
+			output:           `[{"name": "get_current_weather", "parameters": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "parameters": {"format":"celsius","location":"Toronto, Canada"}}]</tool_call> some tokens after`,
+			expectedToolCall: []api.ToolCall{t1, t2},
+			expectedTokens:   "",
+		},
+		{
+			name:             "model without prefix in template, no prefix in output, tokens before",
+			model:            "llama3.2",
+			output:           `some tokens before [{"name": "get_current_weather", "parameters": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "parameters": {"format":"celsius","location":"Toronto, Canada"}}]`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `some tokens before [{"name": "get_current_weather", "parameters": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "parameters": {"format":"celsius","location":"Toronto, Canada"}}]`,
+		},
+		{
+			name:             "model without prefix in template, prefix in output, tokens after",
+			model:            "llama3.2",
+			output:           `<tool_call> [{"name": "get_current_weather", "parameters": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "parameters": {"format":"celsius","location":"Toronto, Canada"}}]</tool_call> some tokens after`,
+			expectedToolCall: []api.ToolCall{},
+			expectedTokens:   `<tool_call> [{"name": "get_current_weather", "parameters": {"format":"fahrenheit","location":"San Francisco, CA"}} {"name": "get_current_weather", "parameters": {"format":"celsius","location":"Toronto, Canada"}}]</tool_call> some tokens after`,
+		},
+	}
+
+	var tools []api.Tool
+	if err := json.Unmarshal(readFile(t, p, "tools.json").Bytes(), &tools); err != nil {
+		t.Fatal(err)
+	}
+
+	var messages []api.Message
+	if err := json.Unmarshal(readFile(t, p, "messages.json").Bytes(), &messages); err != nil {
+		t.Fatal(err)
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			tmpl, err := template.Parse(readFile(t, p, fmt.Sprintf("%s.gotmpl", tt.model)).String())
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			t.Run("template", func(t *testing.T) {
+				actual := &bytes.Buffer{} // Create new buffer for each test
+				if err := tmpl.Execute(actual, template.Values{Tools: tools, Messages: messages}); err != nil {
+					t.Fatal(err)
+				}
+
+				if diff := cmp.Diff(actual.String(), readFile(t, p, fmt.Sprintf("%s.out", tt.model)).String()); diff != "" {
+					t.Errorf("mismatch (-got +want):\n%s", diff)
+				}
+			})
+
+			t.Run("parse", func(t *testing.T) {
+				tp, err := NewParser(tmpl.Template)
+				if err != nil {
+					t.Fatal(err)
+				}
+				got := []api.ToolCall{}
+				var gotTokens strings.Builder
+
+				tokens := strings.Fields(tt.output)
+				for _, tok := range tokens {
+					s := " " + tok
+
+					toolCalls, content := tp.Add(s)
+					if len(content) > 0 {
+						gotTokens.WriteString(content)
+					} else if len(toolCalls) > 0 {
+						got = append(got, toolCalls...)
+					}
+				}
+
+				// Compare tool calls if we expect any
+				if diff := cmp.Diff(got, tt.expectedToolCall); diff != "" {
+					t.Errorf("tool calls mismatch (-got +want):\n%s", diff)
+				}
+
+				// Compare tokens if we expect any
+				stripped := strings.TrimSpace(gotTokens.String())
+				if diff := cmp.Diff(stripped, tt.expectedTokens); diff != "" {
+					t.Log("actualTokens", stripped, "expectedTokens", tt.expectedTokens)
+					t.Errorf("tokens mismatch (-got +want):\n%s", diff)
+				}
+			})
+		})
+	}
+}

tools/tools_utils.go

@@ -0,0 +1,227 @@
+package tools
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"log/slog"
+	"slices"
+	"strings"
+	gotmpl "text/template"
+	"text/template/parse"
+
+	"github.com/ollama/ollama/api"
+	"github.com/ollama/ollama/template"
+)
+
+// extractToolCallsFormat traverses a template AST to find text that follows a ".ToolCalls" condition.
+// It walks the template nodes looking for if-statements containing ".ToolCalls" and extracts any
+// immediate text nodes that follow. This is used to identify tool call prefixes and formatting.
+//
+// Returns:
+//   - string: The extracted text following the first ".ToolCalls" condition found
+//   - bool: Whether a ".ToolCalls" condition was found in the template
+func extractToolCallsFormat(tmpl *gotmpl.Template) (string, bool) {
+	if tmpl == nil || tmpl.Tree == nil {
+		slog.Debug("template or tree is nil")
+		return "", false
+	}
+
+	var result string
+	var found bool
+
+	var walk func(nodes []parse.Node)
+	walk = func(nodes []parse.Node) {
+		for _, node := range nodes {
+			if found {
+				return
+			}
+
+			switch n := node.(type) {
+			case *parse.IfNode:
+				if isToolCallsNode(n) {
+					// Collect immediate TextNode(s) at start of IfNode's list
+					var sb strings.Builder
+					for _, innerNode := range n.List.Nodes {
+						if tn, ok := innerNode.(*parse.TextNode); ok {
+							sb.Write(tn.Text)
+						} else {
+							// Stop at first non-text node
+							break
+						}
+					}
+					result = sb.String()
+					found = true
+					return
+				}
+				// Recurse into child nodes
+				walk(n.List.Nodes)
+				if n.ElseList != nil {
+					walk(n.ElseList.Nodes)
+				}
+			case *parse.ListNode:
+				walk(n.Nodes)
+			case *parse.RangeNode:
+				walk(n.List.Nodes)
+				if n.ElseList != nil {
+					walk(n.ElseList.Nodes)
+				}
+			case *parse.WithNode:
+				walk(n.List.Nodes)
+				if n.ElseList != nil {
+					walk(n.ElseList.Nodes)
+				}
+			default:
+				// Continue to next node
+				continue
+			}
+		}
+	}
+
+	walk(tmpl.Tree.Root.Nodes)
+	return result, found
+}
+
+// isToolCallsNode detects if a node's condition includes ".ToolCalls"
+func isToolCallsNode(n *parse.IfNode) bool {
+	for _, cmd := range n.Pipe.Cmds {
+		for _, arg := range cmd.Args {
+			if field, ok := arg.(*parse.FieldNode); ok {
+				if slices.Contains(field.Ident, "ToolCalls") {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
+func toolPrefix(tmpl *gotmpl.Template) string {
+	tokenText, ok := extractToolCallsFormat(tmpl)
+	if !ok {
+		return ""
+	}
+	tokenText = strings.TrimSpace(tokenText)
+	tokenText = strings.ReplaceAll(tokenText, "\r", "")
+	tokenText = strings.ReplaceAll(tokenText, "\n", " ")
+
+	return tokenText
+}
+
+// toolTemplate creates a subtree from the node that ranges over .ToolCalls
+//
+// Returns:
+//   - *gotmpl.Template: The subtree containing the .ToolCalls range
+//   - error: Error if parsing failed
+func toolTemplate(t *template.Template) (*gotmpl.Template, error) {
+	tmpl := t.Subtree(func(n parse.Node) bool {
+		if t, ok := n.(*parse.RangeNode); ok {
+			return slices.Contains(template.Identifiers(t.Pipe), "ToolCalls")
+		}
+
+		return false
+	})
+
+	if tmpl == nil {
+		return nil, errors.New("failed to find tool template")
+	}
+
+	return tmpl, nil
+}
+
+// suffixOverlap returns the index in s where the longest suffix overlap with prefix begins
+//
+// Returns:
+//   - int: The starting index in s where the suffix overlap begins
+func suffixOverlap(s, prefix string) int {
+	max := min(len(prefix), len(s))
+	for i := max; i > 0; i-- {
+		if strings.HasSuffix(s, prefix[:i]) {
+			return len(s) - i
+		}
+	}
+	return -1
+}
+
+// extractToolArgs executes a template with a known tool call format to extract the name and arguments
+//
+// Returns:
+//   - string: The name of the tool call
+//   - string: The arguments of the tool call
+//   - error: Error if parsing failed
+func extractToolArgs(tmpl *gotmpl.Template) (name, arguments string, err error) {
+	var b bytes.Buffer
+	if err := tmpl.Execute(&b, map[string][]api.ToolCall{
+		"ToolCalls": {
+			{
+				Function: api.ToolCallFunction{
+					Name: "@@name@@",
+					Arguments: api.ToolCallFunctionArguments{
+						"@@argument@@": 1,
+					},
+				},
+			},
+		},
+	}); err != nil {
+		return "", "", err
+	}
+
+	var obj any
+	err = json.Unmarshal(b.Bytes(), &obj)
+	if err != nil {
+		return "", "", err
+	}
+
+	var objs []map[string]any
+	switch v := obj.(type) {
+	case map[string]any:
+		objs = []map[string]any{v}
+	case []map[string]any:
+		objs = v
+	case []any:
+		objs = collect(v)
+	}
+	if len(objs) == 0 {
+		return "", "", errors.New("no template objects found")
+	}
+
+	// find the keys that correspond to the name and arguments fields
+	for k, v := range objs[0] {
+		switch v.(type) {
+		case string:
+			name = k
+		case map[string]any:
+			arguments = k
+		}
+	}
+
+	if name == "" || arguments == "" {
+		slog.Debug("missing required fields in tool call template", "name", name, "arguments", arguments)
+		return "", "", errors.New("missing required fields in tool call template")
+	}
+
+	return name, arguments, nil
+}
+
+// collect recursively traverses an object to collect all nested maps
+//
+// Returns:
+//   - []map[string]any: A slice of all nested maps found in the object
+func collect(obj any) []map[string]any {
+	var all []map[string]any
+	switch o := obj.(type) {
+	case map[string]any:
+		all = append(all, o)
+		for _, v := range o {
+			all = append(all, collect(v)...)
+		}
+	case []any:
+		for _, v := range o {
+			all = append(all, collect(v)...)
+		}
+	default:
+		return nil
+	}
+
+	return all
+}

tools/tools_utils_test.go

@@ -0,0 +1,464 @@
+package tools
+
+import (
+	"testing"
+	gotmpl "text/template"
+
+	"github.com/ollama/ollama/template"
+)
+
+func TestExtractToolCallsFormat(t *testing.T) {
+	cases := []struct {
+		name     string
+		template string
+		want     string
+		found    bool
+	}{
+		{
+			name:     "nil template",
+			template: "",
+			want:     "",
+			found:    false,
+		},
+		{
+			name:     "basic tool call with text",
+			template: "{{if .ToolCalls}}Hello world{{end}}",
+			want:     "Hello world",
+			found:    true,
+		},
+		{
+			name:     "tool call with json format",
+			template: "{{if .ToolCalls}}```json\n{{end}}",
+			want:     "```json\n",
+			found:    true,
+		},
+		{
+			name:     "tool call in range",
+			template: "{{range .ToolCalls}}tool: {{.}}{{end}}",
+			want:     "",
+			found:    false,
+		},
+		{
+			name:     "tool call with multiple text nodes",
+			template: "{{if .ToolCalls}}First text{{if .Something}}inner{{end}}Second text{{end}}",
+			want:     "First text",
+			found:    true,
+		},
+		{
+			name:     "nested if without tool calls",
+			template: "{{if .Something}}{{if .OtherThing}}text{{end}}{{end}}",
+			want:     "",
+			found:    false,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			tmpl, err := gotmpl.New("test").Parse(tc.template)
+			if err != nil && tc.template != "" {
+				t.Fatalf("failed to parse template: %v", err)
+			}
+
+			got, found := extractToolCallsFormat(tmpl)
+			if got != tc.want {
+				t.Errorf("got text %q, want %q", got, tc.want)
+			}
+			if found != tc.found {
+				t.Errorf("got found %v, want %v", found, tc.found)
+			}
+		})
+	}
+}
+
+func TestToolPrefix(t *testing.T) {
+	cases := []struct {
+		name     string
+		template string
+		want     string
+	}{
+		{
+			name:     "basic tool call with action prefix",
+			template: "{{if .ToolCalls}}Action: ```json{{end}}",
+			want:     "Action: ```json",
+		},
+		{
+			name:     "incomplete functools bracket",
+			template: "{{if .ToolCalls}}functools[{{end}}",
+			want:     "functools[",
+		},
+		{
+			name:     "tool call with angle brackets",
+			template: "{{if .ToolCalls}}Hello, world! <tool_call>{{end}}",
+			want:     "Hello, world! <tool_call>",
+		},
+		{
+			name:     "multiple tool call formats",
+			template: "{{if .ToolCalls}}[tool_call] <tool_call>{{end}}",
+			want:     "[tool_call] <tool_call>",
+		},
+		{
+			name:     "single angle bracket tool call",
+			template: "{{if .ToolCalls}}<tool_call>{{end}}",
+			want:     "<tool_call>",
+		},
+		{
+			name:     "incomplete angle bracket after tool call",
+			template: "{{if .ToolCalls}}[tool_call] <{{end}}",
+			want:     "[tool_call] <",
+		},
+		{
+			name:     "angle bracket prefix with tool call",
+			template: "{{if .ToolCalls}}> <tool_call>{{end}}",
+			want:     "> <tool_call>",
+		},
+		{
+			name:     "uppercase tool call with incomplete bracket",
+			template: "{{if .ToolCalls}}[TOOL_CALL] [{{end}}",
+			want:     "[TOOL_CALL] [",
+		},
+		{
+			name:     "uppercase tool call with adjacent bracket",
+			template: "{{if .ToolCalls}}[TOOL_CALL][{{end}}",
+			want:     "[TOOL_CALL][",
+		},
+		{
+			name:     "tool call with pipe delimiters",
+			template: "{{if .ToolCalls}}<|tool_call|>{{end}}",
+			want:     "<|tool_call|>",
+		},
+		{
+			name:     "tool with no prefix",
+			template: "{{if .ToolCalls}}{{end}}",
+			want:     "",
+		},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			tmpl, err := gotmpl.New("test").Parse(tt.template)
+			if err != nil {
+				t.Fatalf("failed to parse template: %v", err)
+			}
+			got := toolPrefix(tmpl)
+			if got != tt.want {
+				t.Errorf("ToolToken(%q) = %q; want %q", tt.template, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestToolTemplate(t *testing.T) {
+	cases := []struct {
+		name     string
+		template string
+		want     bool
+	}{
+		{
+			name:     "basic tool call range",
+			template: "{{range .ToolCalls}}test{{end}}",
+			want:     true,
+		},
+		{
+			name:     "no tool calls",
+			template: "{{range .Other}}test{{end}}",
+			want:     false,
+		},
+		{
+			name:     "nested tool calls",
+			template: "{{range .Outer}}{{range .ToolCalls}}test{{end}}{{end}}",
+			want:     true,
+		},
+		{
+			name:     "empty template",
+			template: "",
+			want:     false,
+		},
+		{
+			name:     "tool calls in if statement",
+			template: "{{if .ToolCalls}}test{{end}}",
+			want:     false,
+		},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			tmpl, err := gotmpl.New("test").Parse(tt.template)
+			if err != nil {
+				t.Fatalf("failed to parse template: %v", err)
+			}
+
+			parsed, err := template.Parse(tmpl.Root.String())
+			if err != nil {
+				t.Fatalf("failed to parse template: %v", err)
+			}
+
+			_, err = toolTemplate(parsed)
+			if err != nil && tt.want {
+				t.Errorf("toolTemplate() = %v; want %v", err, tt.want)
+			}
+		})
+	}
+}
+
+func TestSuffixOverlap(t *testing.T) {
+	cases := []struct {
+		name string
+		s    string
+		d    string
+		want int
+	}{
+		{
+			name: "no overlap",
+			s:    "hello world",
+			d:    "<tool_call>",
+			want: -1,
+		},
+		{
+			name: "full overlap",
+			s:    "<tool_call>",
+			d:    "<tool_call>",
+			want: 0,
+		},
+		{
+			name: "partial overlap",
+			s:    "text <tool_call>",
+			d:    "<tool_call>",
+			want: 5,
+		},
+		{
+			name: "delimiter longer than string",
+			s:    "<tool>",
+			d:    "<tool_call>",
+			want: -1,
+		},
+		{
+			name: "empty string",
+			s:    "",
+			d:    "<tool_call>",
+			want: -1,
+		},
+		{
+			name: "empty delimiter",
+			s:    "<tool_call>",
+			d:    "",
+			want: -1,
+		},
+		{
+			name: "single char overlap",
+			s:    "test<",
+			d:    "<tool_call>",
+			want: 4,
+		},
+		{
+			name: "partial tool call",
+			s:    "hello <tool_",
+			d:    "<tool_call>",
+			want: 6,
+		},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			got := suffixOverlap(tt.s, tt.d)
+			if got != tt.want {
+				t.Errorf("suffixOverlap(%q, %q) = %d; want %d", tt.s, tt.d, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestExtractToolArgs(t *testing.T) {
+	cases := []struct {
+		name     string
+		template string
+		want     string
+		ok       bool
+	}{
+		{
+			name:     "basic tool call with text after",
+			template: `{{if .ToolCalls}}tool response{{end}}`,
+			want:     "tool response",
+			ok:       true,
+		},
+		{
+			name:     "tool call with mixed content after",
+			template: `{{if .ToolCalls}}<tool_call>{{.Something}}{{end}}`,
+			want:     "<tool_call>",
+			ok:       true,
+		},
+		{
+			name:     "tool call with no text after",
+			template: `{{if .ToolCalls}}{{.Something}}{{end}}`,
+			want:     "",
+			ok:       true,
+		},
+		{
+			name:     "nested tool call",
+			template: `{{if .Something}}{{if .ToolCalls}}[TOOL_CALL]{{end}}{{end}}`,
+			want:     "[TOOL_CALL]",
+			ok:       true,
+		},
+		{
+			name:     "no tool calls",
+			template: `{{if .Something}}no tools here{{end}}`,
+			want:     "",
+			ok:       false,
+		},
+		{
+			name:     "empty template",
+			template: ``,
+			want:     "",
+			ok:       false,
+		},
+		{
+			name:     "multiple tool calls sections",
+			template: `{{if .ToolCalls}}first{{end}}{{if .ToolCalls}}second{{end}}`,
+			want:     "first",
+			ok:       true,
+		},
+		{
+			name:     "range over tool calls",
+			template: `{{if .ToolCalls}}{{range .ToolCalls}}tool{{end}}{{end}}`,
+			want:     "",
+			ok:       true,
+		},
+		{
+			name:     "tool calls with pipe delimiters",
+			template: `{{if .ToolCalls}}<|tool|>{{end}}`,
+			want:     "<|tool|>",
+			ok:       true,
+		},
+		{
+			name:     "tool calls with nested template",
+			template: `{{if .ToolCalls}}{{template "tool" .}}{{end}}`,
+			want:     "",
+			ok:       true,
+		},
+		{
+			name:     "tool calls with whitespace variations",
+			template: `{{if .ToolCalls}}  tool  {{end}}`,
+			want:     "  tool  ",
+			ok:       true,
+		},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			tmpl, err := gotmpl.New("test").Parse(tt.template)
+			if err != nil {
+				t.Fatalf("failed to parse template: %v", err)
+			}
+
+			got, ok := extractToolCallsFormat(tmpl)
+			if got != tt.want {
+				t.Errorf("TextAfterToolCalls() got = %q, want %q", got, tt.want)
+			}
+			if ok != tt.ok {
+				t.Errorf("TextAfterToolCalls() ok = %v, want %v", ok, tt.ok)
+			}
+		})
+	}
+}
+
+func TestCollect(t *testing.T) {
+	cases := []struct {
+		name string
+		obj  any
+		want []map[string]any
+	}{
+		{
+			name: "simple map",
+			obj: map[string]any{
+				"key": "value",
+			},
+			want: []map[string]any{
+				{"key": "value"},
+			},
+		},
+		{
+			name: "nested map",
+			obj: map[string]any{
+				"outer": map[string]any{
+					"inner": "value",
+				},
+			},
+			want: []map[string]any{
+				{"outer": map[string]any{"inner": "value"}},
+				{"inner": "value"},
+			},
+		},
+		{
+			name: "array of maps",
+			obj: []any{
+				map[string]any{"key1": "val1"},
+				map[string]any{"key2": "val2"},
+			},
+			want: []map[string]any{
+				{"key1": "val1"},
+				{"key2": "val2"},
+			},
+		},
+		{
+			name: "deeply nested",
+			obj: map[string]any{
+				"l1": map[string]any{
+					"l2": map[string]any{
+						"l3": "value",
+					},
+				},
+			},
+			want: []map[string]any{
+				{"l1": map[string]any{"l2": map[string]any{"l3": "value"}}},
+				{"l2": map[string]any{"l3": "value"}},
+				{"l3": "value"},
+			},
+		},
+		{
+			name: "non-map value",
+			obj:  "string",
+			want: nil,
+		},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			got := collect(tt.obj)
+			if len(got) != len(tt.want) {
+				t.Errorf("collect() got %d maps, want %d", len(got), len(tt.want))
+				return
+			}
+
+			// Compare each map in the result
+			for i := range tt.want {
+				if !mapsEqual(got[i], tt.want[i]) {
+					t.Errorf("collect() map[%d] = %v, want %v", i, got[i], tt.want[i])
+				}
+			}
+		})
+	}
+}
+
+// mapsEqual compares two maps for deep equality
+func mapsEqual(m1, m2 map[string]any) bool {
+	if len(m1) != len(m2) {
+		return false
+	}
+	for k, v1 := range m1 {
+		v2, ok := m2[k]
+		if !ok {
+			return false
+		}
+		switch val1 := v1.(type) {
+		case map[string]any:
+			val2, ok := v2.(map[string]any)
+			if !ok || !mapsEqual(val1, val2) {
+				return false
+			}
+		default:
+			if v1 != v2 {
+				return false
+			}
+		}
+	}
+	return true
+}