refactor(agent): replace XML api_call with native function calling

Migrate the Telegram bot agent from an XML tag hack (<api_call>) to
OpenAI-native function calling via CallWithRequestFull.

Key changes:
- mcp/interface.go: add parseMCPResponseFull to clientHooks interface
- mcp/client.go: route callWithRequestFull through hooks for overridability
- mcp/claude_client.go: override parseMCPResponseFull for Claude response
  format (tool_use blocks instead of choices[].message.tool_calls)
- telegram/agent/agent.go: rewrite Run() to use CallWithRequestFull;
  define api_request tool with JSON Schema; implement tool-call loop
  with role="tool" result messages; remove XML parsing entirely
- telegram/agent/apicall.go: remove parseAPICall (dead code)
- telegram/agent/prompt.go: simplify — remove XML format instructions,
  replace with concise api_request tool usage instructions
- telegram/agent/agent_test.go: rebuild all tests using LLMResponse
  objects; add TestNarrationStructurallyImpossible, TestOnChunkCalledWithFinalReply,
  TestToolCallIDPropagated; remove XML-specific tests

Architecture advantage: with native function calling, the LLM returns
EITHER ToolCalls OR Content — never both. Narration is now structurally
impossible at the protocol level, not just enforced by prompt rules.

All 11 agent tests pass. mcp package tests pass.
This commit is contained in:
tinkle-community
2026-03-08 17:10:07 +08:00
parent 5f47dd13db
commit 9fcf44af65
8 changed files with 472 additions and 320 deletions

View File

@@ -12,8 +12,39 @@ import (
const maxIterations = 10
// apiRequestTool is the single tool exposed to the LLM.
// Native function calling means the LLM returns EITHER ToolCalls OR Content — never both.
// This makes narration structurally impossible: text cannot appear alongside a tool call.
var apiRequestTool = mcp.Tool{
Type: "function",
Function: mcp.FunctionDef{
Name: "api_request",
Description: "Call the NOFX trading system REST API",
Parameters: map[string]any{
"type": "object",
"properties": map[string]any{
"method": map[string]any{
"type": "string",
"enum": []string{"GET", "POST", "PUT", "DELETE"},
"description": "HTTP method",
},
"path": map[string]any{
"type": "string",
"description": "API path; include query params in path: /api/positions?trader_id=xxx",
},
"body": map[string]any{
"type": "object",
"description": "Request body; use {} for GET requests",
},
},
"required": []string{"method", "path", "body"},
},
},
}
// Agent is a stateful AI agent for one Telegram chat.
// It has a single tool (api_call) and an unbounded decision loop.
// It exposes a single "api_request" tool and runs a loop until the LLM
// returns a plain-text reply (no tool calls).
type Agent struct {
apiTool *apiCallTool
getLLM func() mcp.AIClient
@@ -34,17 +65,15 @@ func New(apiPort int, botToken, userID string, getLLM func() mcp.AIClient, syste
}
// GenerateBotToken creates a long-lived JWT for the bot's internal API calls.
// userID must match the actual registered user's ID so that bot-made changes
// are visible in the frontend (they share the same user namespace).
// userID must match the actual registered user's ID so bot-made changes
// are visible in the frontend (shared user namespace).
func GenerateBotToken(userID string) (string, error) {
return auth.GenerateJWT(userID, "bot@internal")
}
// buildAccountContext fetches the live account state (models, exchanges, strategies, traders,
// and per-trader account summary + statistics) via the local API and returns it as a formatted
// string for injection into the LLM context. This gives the LLM immediate awareness of what
// is already configured and the current financial state, so it never asks the user for
// information that already exists.
// and per-trader account summary + statistics) and returns it as a formatted string for
// injection into the LLM context at the start of each conversation.
func (a *Agent) buildAccountContext() string {
type q struct {
label string
@@ -91,137 +120,104 @@ func (a *Agent) buildAccountContext() string {
return sb.String()
}
// Run processes one user message through the agent loop.
// Loop: LLM decides -> if <api_call>: execute, append result, loop -> if no tag: return reply.
// Run processes one user message through the native function-calling agent loop.
//
// On the first message of a conversation, the current account state (models, exchanges,
// strategies, traders) is automatically fetched and injected so the LLM knows what is
// already configured without asking the user to repeat themselves.
// Architecture:
// - LLM receives the api_request tool definition alongside conversation history.
// - LLM response is EITHER ToolCalls (execute API) OR Content (final reply) — never both.
// This is enforced by the protocol: narration is structurally impossible.
// - Loop continues until the LLM returns a plain-text reply (no tool calls).
//
// onChunk is optional. When non-nil, each LLM call is streamed:
// - Chunks are forwarded to onChunk until an <api_call> tag appears in the accumulated text.
// - After an api_call iteration completes, onChunk("⏳") resets the display to a thinking indicator.
// - The final reply is streamed progressively via onChunk.
// On the first message of a conversation the live account state is fetched and injected.
// onChunk is optional; when set it is called once with the complete final reply text.
func (a *Agent) Run(userMessage string, onChunk func(string)) string {
llm := a.getLLM()
if llm == nil {
return "AI assistant unavailable. Please configure an AI model in the Web UI."
}
// Build turn messages: history context prefix + current user message.
// On the very first message (no history), prepend a live account state snapshot so the
// LLM immediately knows what models, exchanges, strategies, and traders are configured.
// Build initial user message: prepend account state on first turn, history on subsequent turns.
histCtx := a.memory.BuildContext()
var firstMsg string
var firstUserContent string
if histCtx == "" {
// First message in this conversation — fetch and inject account state.
accountCtx := a.buildAccountContext()
firstMsg = accountCtx + "\n[User Message]\n" + userMessage
firstUserContent = accountCtx + "\n[User Message]\n" + userMessage
} else {
firstMsg = histCtx + "\n---\nUser: " + userMessage
firstUserContent = histCtx + "\n---\nUser: " + userMessage
}
turnMsgs := []mcp.Message{mcp.NewUserMessage(firstMsg)}
var lastResp string
turnMsgs := []mcp.Message{mcp.NewUserMessage(firstUserContent)}
for i := 0; i < maxIterations; i++ {
req, err := mcp.NewRequestBuilder().
WithSystemPrompt(a.systemPrompt).
AddConversationHistory(turnMsgs).
AddTool(apiRequestTool).
WithToolChoice("auto").
Build()
if err != nil {
logger.Errorf("Agent: failed to build request: %v", err)
break
}
var resp string
if onChunk != nil {
// Stream this call; suppress chunks once an <api_call> tag appears.
// Also hold back the last (len("<api_call>")-1) chars of accumulated text to
// avoid showing partial opening tags (e.g. "<", "<ap") before we can detect them.
const tagLen = len("<api_call>") // 10
const safeOffset = tagLen - 1 // 9: max prefix of tag we might have received
var apiTagSeen bool
resp, err = llm.CallWithRequestStream(req, func(accumulated string) {
if apiTagSeen {
return
}
if idx := strings.Index(accumulated, "<api_call>"); idx >= 0 {
apiTagSeen = true
// Forward only the text that appeared before the tag.
if display := strings.TrimSpace(accumulated[:idx]); display != "" {
onChunk(display)
}
return
}
// Forward only the "safe" prefix — hold back the last safeOffset chars
// in case they are the beginning of an <api_call> tag.
if safe := len(accumulated) - safeOffset; safe > 0 {
onChunk(accumulated[:safe])
}
})
} else {
resp, err = llm.CallWithRequest(req)
}
resp, err := llm.CallWithRequestFull(req)
if err != nil {
logger.Errorf("Agent: LLM call failed (iteration %d): %v", i+1, err)
return "AI assistant temporarily unavailable. Please try again."
}
lastResp = resp
apiReq, textBefore := parseAPICall(resp)
if apiReq == nil {
// No api_call tag — LLM gave a final answer (already streamed if onChunk set).
reply := stripAPICallTag(strings.TrimSpace(resp))
// No tool calls → LLM returned a final text reply.
if len(resp.ToolCalls) == 0 {
reply := strings.TrimSpace(resp.Content)
if onChunk != nil {
onChunk(reply)
}
a.memory.Add("user", userMessage)
a.memory.Add("assistant", reply)
return reply
}
// api_call iteration — reset display to thinking indicator before executing.
// Tool call iteration — show thinking indicator.
if onChunk != nil {
onChunk("⏳")
}
logger.Infof("Agent: iter=%d %s %s", i+1, apiReq.Method, apiReq.Path)
result := a.apiTool.execute(apiReq)
// Append assistant message carrying the tool calls (no content field).
turnMsgs = append(turnMsgs, mcp.Message{
Role: "assistant",
ToolCalls: resp.ToolCalls,
})
if textBefore != "" {
turnMsgs = append(turnMsgs, mcp.NewAssistantMessage(textBefore))
}
turnMsgs = append(turnMsgs, mcp.NewUserMessage(
fmt.Sprintf("[API result: %s %s]\n%s", apiReq.Method, apiReq.Path, result),
))
}
// Safety: max iterations reached — ask LLM for a final summary (non-streaming).
logger.Warnf("Agent: max iterations (%d) reached", maxIterations)
turnMsgs = append(turnMsgs, mcp.NewUserMessage("Please summarize the results and give the user a final reply."))
if finalReq, err := mcp.NewRequestBuilder().
WithSystemPrompt(a.systemPrompt).
AddConversationHistory(turnMsgs).
Build(); err == nil {
if finalResp, err := llm.CallWithRequest(finalReq); err == nil {
lastResp = finalResp
// Execute each tool call and append the results as tool messages.
for _, tc := range resp.ToolCalls {
var apiReq apiRequest
if err := json.Unmarshal([]byte(tc.Function.Arguments), &apiReq); err != nil {
logger.Errorf("Agent: invalid tool args for call %s: %v", tc.ID, err)
turnMsgs = append(turnMsgs, mcp.Message{
Role: "tool",
ToolCallID: tc.ID,
Content: fmt.Sprintf(`{"error":"invalid arguments: %s"}`, err.Error()),
})
continue
}
logger.Infof("Agent: iter=%d tool=%s %s %s", i+1, tc.ID, apiReq.Method, apiReq.Path)
result := a.apiTool.execute(&apiReq)
turnMsgs = append(turnMsgs, mcp.Message{
Role: "tool",
ToolCallID: tc.ID,
Content: result,
})
}
}
reply := stripAPICallTag(strings.TrimSpace(lastResp))
// Safety: max iterations reached.
logger.Warnf("Agent: max iterations (%d) reached for message: %q", maxIterations, userMessage)
reply := "操作已完成,请检查您的账户查看最新状态。"
a.memory.Add("user", userMessage)
a.memory.Add("assistant", reply)
return reply
}
// stripAPICallTag removes any <api_call>...</api_call> fragment from s.
// Used as a defensive layer to ensure tags never leak to the user.
func stripAPICallTag(s string) string {
if idx := strings.Index(s, "<api_call>"); idx >= 0 {
return strings.TrimSpace(s[:idx])
}
return s
}
// ResetMemory clears conversation history (called on /start).
func (a *Agent) ResetMemory() {
a.memory.ResetFull()