Support configuring effort alongside model

internal/codex/session.go

@@ -28,6 +28,7 @@ import (
 type Options struct {
 	Cwd        string
 	Model      string
+	Effort     string
 	Resume     string
 	ForkFrom   string
 	ForkAt     string
@@ -81,10 +82,12 @@ type Session struct {
 	pendingMu sync.Mutex
 	pending   map[int64]chan rpcResult
 
-	stateMu  sync.Mutex
-	threadID string
-	turnID   string
-	model    string
+	stateMu   sync.Mutex
+	threadID  string
+	turnID    string
+	model     string
+	effort    string
+	effortSet bool
 
 	servers  map[string]*mcp.Server
 	reminder string
@@ -113,6 +116,9 @@ func Start(ctx context.Context, opts Options) (*Session, error) {
 
 func (s *Session) serveHooks(opts Options) (map[string]any, error) {
 	config := map[string]any{}
+	if opts.Effort != "" {
+		config["model_reasoning_effort"] = opts.Effort
+	}
 	if len(opts.StdioMCP) > 0 {
 		config["mcp_servers"] = stdioConfig(opts.StdioMCP)
 	}
@@ -354,12 +360,44 @@ func (s *Session) ID() string {
 	return s.threadID
 }
 
-func (s *Session) SetModel(model string) {
+func (s *Session) SetModel(model, effort string) {
 	s.stateMu.Lock()
 	s.model = model
+	s.effort = effort
+	s.effortSet = true
 	s.stateMu.Unlock()
 }
 
+func (s *Session) defaultEffort(ctx context.Context, model string) (string, error) {
+	cursor := ""
+	for {
+		resp := struct {
+			Data []struct {
+				Model                  string `json:"model"`
+				DefaultReasoningEffort string `json:"defaultReasoningEffort"`
+			} `json:"data"`
+			NextCursor string `json:"nextCursor"`
+		}{}
+		params := map[string]any{"includeHidden": true}
+		if cursor != "" {
+			params["cursor"] = cursor
+		}
+		err := s.Call(ctx, "model/list", params, &resp)
+		if err != nil {
+			return "", fmt.Errorf("list models: %w", err)
+		}
+		for _, m := range resp.Data {
+			if m.Model == model {
+				return m.DefaultReasoningEffort, nil
+			}
+		}
+		if resp.NextCursor == "" {
+			return "", fmt.Errorf("codex lists no model %s to read its default effort from", model)
+		}
+		cursor = resp.NextCursor
+	}
+}
+
 func (s *Session) Send(ctx context.Context, text string, images ...agentinput.Image) (Turn, error) {
 	input := []UserInput{}
 	for _, img := range images {
@@ -373,9 +411,19 @@ func (s *Session) Send(ctx context.Context, text string, images ...agentinput.Im
 	}
 
 	s.stateMu.Lock()
-	params := TurnStartParams{ThreadID: s.threadID, Input: input, Model: s.model}
+	params := TurnStartParams{ThreadID: s.threadID, Input: input, Model: s.model, Effort: ReasoningEffort(s.effort)}
+	reset := s.effortSet && s.effort == ""
 	s.model = ""
+	s.effort = ""
+	s.effortSet = false
 	s.stateMu.Unlock()
+	if reset {
+		effort, err := s.defaultEffort(ctx, params.Model)
+		if err != nil {
+			return Turn{}, err
+		}
+		params.Effort = ReasoningEffort(effort)
+	}
 	if s.reminder != "" {
 		params.AdditionalContext = map[string]AdditionalContextEntry{
 			"byre": {Kind: AdditionalContextKindApplication, Value: s.reminder},