Changeset 0.7.2 (#40)

server/providers/provider.go

@@ -2,6 +2,7 @@ package providers
 
 import (
 	"context"
+	"encoding/json"
 )
 
 // ── Provider Interface ──────────────────────
@@ -37,8 +38,39 @@ type ProviderConfig struct {
 
 // Message represents a chat message in the conversation.
 type Message struct {
-	Role    string `json:"role"`    // user, assistant, system
+	Role    string `json:"role"`    // user, assistant, system, tool
 	Content string `json:"content"`
+
+	// Tool calling fields (assistant → tool_calls, tool → tool_call_id)
+	ToolCalls  []ToolCall `json:"tool_calls,omitempty"`   // set when assistant requests tools
+	ToolCallID string     `json:"tool_call_id,omitempty"` // set for role="tool" result messages
+	Name       string     `json:"name,omitempty"`         // tool name for role="tool"
+}
+
+// ToolCall represents a function call requested by the LLM.
+type ToolCall struct {
+	ID       string       `json:"id"`
+	Type     string       `json:"type"` // "function"
+	Function FunctionCall `json:"function"`
+}
+
+// FunctionCall is the function name and JSON arguments.
+type FunctionCall struct {
+	Name      string `json:"name"`
+	Arguments string `json:"arguments"`
+}
+
+// ToolDef describes a tool available to the LLM.
+type ToolDef struct {
+	Type     string       `json:"type"` // "function"
+	Function FunctionDef  `json:"function"`
+}
+
+// FunctionDef is the schema for a tool function.
+type FunctionDef struct {
+	Name        string          `json:"name"`
+	Description string          `json:"description"`
+	Parameters  json.RawMessage `json:"parameters"`
 }
 
 // CompletionRequest is the normalized request sent to any provider.
@@ -49,15 +81,17 @@ type CompletionRequest struct {
 	Temperature *float64  `json:"temperature,omitempty"`
 	TopP        *float64  `json:"top_p,omitempty"`
 	Stream      bool      `json:"stream,omitempty"`
+	Tools       []ToolDef `json:"tools,omitempty"` // available tools for function calling
 }
 
 // CompletionResponse is the normalized non-streaming response.
 type CompletionResponse struct {
-	Content      string `json:"content"`
-	Model        string `json:"model"`
-	FinishReason string `json:"finish_reason"`
-	InputTokens  int    `json:"input_tokens"`
-	OutputTokens int    `json:"output_tokens"`
+	Content      string     `json:"content"`
+	Model        string     `json:"model"`
+	FinishReason string     `json:"finish_reason"`
+	InputTokens  int        `json:"input_tokens"`
+	OutputTokens int        `json:"output_tokens"`
+	ToolCalls    []ToolCall `json:"tool_calls,omitempty"` // set when finish_reason is "tool_calls"
 }
 
 // StreamEvent is a single chunk from a streaming response.
@@ -69,8 +103,13 @@ type StreamEvent struct {
 	Done bool `json:"done,omitempty"`
 
 	// FinishReason is set on the final event.
+	// "stop" = normal, "tool_calls" = LLM wants to call tools.
 	FinishReason string `json:"finish_reason,omitempty"`
 
+	// ToolCalls accumulates tool call data during streaming.
+	// Fully populated on the final event when FinishReason is "tool_calls".
+	ToolCalls []ToolCall `json:"tool_calls,omitempty"`
+
 	// Model echoes back the model used.
 	Model string `json:"model,omitempty"`