From 45959cb79d0b7940c6bbb449b8f28e7cf6068ff0 Mon Sep 17 00:00:00 2001
From: Levi Neely <141506390+lneely@users.noreply.github.com>
Date: Sun, 17 May 2026 00:19:55 +0200
Subject: [PATCH] agent: apply config backend/model when switching agents via
 /agent

---
 pkg/agent/commands.go | 13 +++++++++++++
 pkg/agent/core.go     | 10 ++++++++++
 2 files changed, 23 insertions(+)

diff --git a/pkg/agent/commands.go b/pkg/agent/commands.go
index 45f5558..f16ee47 100644
--- a/pkg/agent/commands.go
+++ b/pkg/agent/commands.go
@@ -207,6 +207,19 @@ func (s *agent) handleCommand(ctx context.Context, input string, handler EventHa
 			}
 			d := s.newDispatcher()
 			env := BuildAgentEnv(cfg, d, s.cwd)
+			if env.Backend != "" {
+				newBe, err := s.newBackend(env.Backend)
+				if err != nil {
+					handler(infoEvent(fmt.Sprintf("error: backend %q: %v", env.Backend, err)))
+					return
+				}
+				if env.Model != "" {
+					newBe.SetModel(env.Model)
+				}
+				s.cfg.Backend = newBe
+			} else if env.Model != "" {
+				s.cfg.Backend.SetModel(env.Model)
+			}
 			s.dispatcher = env.dispatcher
 			s.hooks = env.Hooks
 			s.cfg.preamble = env.preamble
diff --git a/pkg/agent/core.go b/pkg/agent/core.go
index 000ffc3..340c60d 100644
--- a/pkg/agent/core.go
+++ b/pkg/agent/core.go
@@ -38,6 +38,8 @@ type AgentEnv struct {
 	preamble     string
 	genParams    backend.GenerationParams
 	maxSteps     int
+	Backend      string // from config; empty means no override
+	Model        string // from config; empty means no override
 	Messages     []string
 }
 
@@ -136,6 +138,12 @@ func BuildAgentEnv(cfg *config.Config, d tools.Dispatcher, cwd string) AgentEnv
 		}
 	}
 
+	var backendName, modelName string
+	if cfg != nil {
+		backendName = cfg.Backend
+		modelName = cfg.Model
+	}
+
 	return AgentEnv{
 		dispatcher:   d,
 		tools:        allTools,
@@ -145,6 +153,8 @@ func BuildAgentEnv(cfg *config.Config, d tools.Dispatcher, cwd string) AgentEnv
 		preamble:     preamble,
 		genParams:    genParams,
 		maxSteps:     maxSteps,
+		Backend:      backendName,
+		Model:        modelName,
 		Messages:     messages,
 	}
 }