fix(agent): honor ACP iteration limits

Author: cnjack

internal/agent/agent.go

@@ -14,7 +14,35 @@ import (
 	"github.com/cnjack/jcode/internal/toolpolicy"
 )
 
-const maxIterations = 1000
+const defaultMaxIterations = 1000
+
+type agentOptions struct {
+	maxIterations int
+}
+
+// AgentOption configures one ChatModelAgent without changing the defaults used by
+// existing transports.
+type AgentOption func(*agentOptions)
+
+// WithMaxIterations bounds the model/tool loop for the constructed agent.
+// Non-positive values retain the default for backward compatibility.
+func WithMaxIterations(limit int) AgentOption {
+	return func(options *agentOptions) {
+		if limit > 0 {
+			options.maxIterations = limit
+		}
+	}
+}
+
+func resolveAgentOptions(options ...AgentOption) agentOptions {
+	resolved := agentOptions{maxIterations: defaultMaxIterations}
+	for _, apply := range options {
+		if apply != nil {
+			apply(&resolved)
+		}
+	}
+	return resolved
+}
 
 type ApprovalFunc func(ctx context.Context, toolName, toolArgs string) (bool, error)
 
@@ -47,10 +75,12 @@ func NewAgent(
 	approvalFunc ApprovalFunc,
 	middlewares []adk.ChatModelAgentMiddleware,
 	handlers []adk.ChatModelAgentMiddleware,
+	options ...AgentOption,
 ) (*adk.ChatModelAgent, error) {
 	return newAgent(
 		ctx, chatmodel, tools, nil, toolDisclosureGroups{},
 		instruction, approvalFunc, middlewares, handlers,
+		options...,
 	)
 }
 
@@ -64,7 +94,9 @@ func newAgent(
 	approvalFunc ApprovalFunc,
 	middlewares []adk.ChatModelAgentMiddleware,
 	handlers []adk.ChatModelAgentMiddleware,
+	options ...AgentOption,
 ) (*adk.ChatModelAgent, error) {
+	resolvedOptions := resolveAgentOptions(options...)
 	// Handler order is outermost → innermost: tracing middlewares first, then the
 	// tool-search middleware, then the caller's state-rewriting handlers, and
 	// finally the hook + approval + safe-tool-error stack. Tool search must inspect
@@ -138,7 +170,7 @@ func newAgent(
 				Tools: append([]tool.BaseTool(nil), directTools...),
 			},
 		},
-		MaxIterations: maxIterations,
+		MaxIterations: resolvedOptions.maxIterations,
 		Handlers:      enhanced,
 		ModelRetryConfig: &adk.ModelRetryConfig{
 			MaxRetries:  5,

internal/agent/agent_options_test.go

@@ -0,0 +1,23 @@
+package agent
+
+import "testing"
+
+func TestResolveAgentOptionsMaxIterations(t *testing.T) {
+	tests := []struct {
+		name    string
+		options []AgentOption
+		want    int
+	}{
+		{name: "default", want: defaultMaxIterations},
+		{name: "explicit limit", options: []AgentOption{WithMaxIterations(40)}, want: 40},
+		{name: "non-positive limit keeps default", options: []AgentOption{WithMaxIterations(0)}, want: defaultMaxIterations},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := resolveAgentOptions(tt.options...).maxIterations; got != tt.want {
+				t.Fatalf("max iterations = %d, want %d", got, tt.want)
+			}
+		})
+	}
+}

internal/agent/toolsearch_agent.go

@@ -33,6 +33,7 @@ func NewAgentWithToolPlan(
 	approvalFunc ApprovalFunc,
 	middlewares []adk.ChatModelAgentMiddleware,
 	handlers []adk.ChatModelAgentMiddleware,
+	options ...AgentOption,
 ) (*adk.ChatModelAgent, error) {
 	direct, deferred, disclosureGroups, err := executableToolsFromPlan(ctx, plan)
 	if err != nil {
@@ -44,6 +45,7 @@ func NewAgentWithToolPlan(
 	return newAgent(
 		ctx, chatmodel, direct, deferred, disclosureGroups,
 		instruction, approvalFunc, middlewares, handlers,
+		options...,
 	)
 }
 

internal/command/acp.go

@@ -824,6 +824,7 @@ func (a *acpAgent) buildAgentSession(
 			return agent.NewAgent(
 				agentCtx, chatModel, staticTools, sysPrompt,
 				approvalState.RequestApproval, nil, handlers,
+				agent.WithMaxIterations(cfg.MaxIterations),
 			)
 		}
 		toolMode := agent.ToolModeNormal
@@ -839,6 +840,7 @@ func (a *acpAgent) buildAgentSession(
 		return agent.NewAgentWithToolPlan(
 			agentCtx, chatModel, toolPlan, sysPrompt,
 			approvalState.RequestApproval, nil, handlers,
+			agent.WithMaxIterations(cfg.MaxIterations),
 		)
 	}
 	newSessionAgent := func(