23 files changed, 1040 insertions, 143 deletions

diff --git a/PLAN2.md b/PLAN2.md
new file mode 100644
index 0000000..ff518e9
--- /dev/null
+++ b/PLAN2.md
@@ -0,0 +1,28 @@
+# Per-Surface LLM Model Configuration Plan
+
+Goal: allow users to configure distinct LLM models for (1) code completion, (2) code actions, (3) in-editor chat, and (4) the `hexai` CLI while keeping defaults sensible and maintaining backward compatibility. The new options must remain hot-reloadable via the existing runtime config store.
+
+## Phase 1 – Configuration Design
+- [x] Audit current config structures (`internal/appconfig`) and identify the model/temperature fields each surface consumes.
+- [x] Propose TOML schema extensions (e.g., `[models] completion = "..."`) plus environment variable overrides.
+- [x] Define precedence rules and fallback behavior when only a global model is provided.
+- [x] Sketch migration approach (default legacy fields map to all surfaces).
+
+## Phase 2 – Loader & Runtime Store Updates
+- [x] Extend `appconfig` to parse per-surface model settings (and optional temperature overrides) with validation.
+- [x] Update `runtimeconfig.Store` diff/flatten logic to include the new fields and guarantee reload propagation works without restart.
+- [x] Ensure reload summaries list per-surface changes cleanly.
+- [x] Add unit tests covering config parsing, env overrides, and diff output, plus runtime reload coverage.
+
+## Phase 3 – Surface Wiring
+- [x] Completion: adjust LSP completion code to pick the configured completion model, falling back to provider defaults.
+- [x] Code actions: ensure code-action prompts and CLI action runner request the configured model.
+- [x] In-editor chat: pass chat-specific model to chat requests and CLI chat command handling.
+- [x] Hexai CLI: respect the CLI model when building `llm.Config` or request options.
+- [x] Provide logging to confirm which model each surface uses for easier debugging.
+
+## Phase 4 – Validation & Docs
+- [x] Add integration/unit tests covering each surface model selection path.
+- [x] Verify runtime reload switches models without restart (including diff output).
+- [x] Update docs (`docs/configuration.md`, examples) with new keys and environment variables.
+- [x] Announce in scratchpad or release notes placeholder for future update.
diff --git a/SCRATCHPAD.md b/SCRATCHPAD.md
index dba529c..c6b0f54 100644
--- a/SCRATCHPAD.md
+++ b/SCRATCHPAD.md
@@ -13,3 +13,4 @@ This document shows future items and items in progress. Already completed ones a
 * [/] Review documentation
 * [/] Manual review the code 
 * [ ] ASCIInema: Record and share terminal sessions for demos and bug reports
+* [ ] Release notes: highlight per-surface model overrides once bundled
diff --git a/config.toml.example b/config.toml.example
index 9ac6f51..e5a75f4 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -27,6 +27,21 @@ inline_close = ">"                  # single-character
 chat_suffix   = ">"                 # single-character
 chat_prefixes = ["?", "!", ":", ";"]  # single-character items
 
+[models]
+# Shorthand string form per surface
+# completion = "gpt-4o-mini"
+# chat = "gpt-4.1"
+
+[models.code_action]
+# model = "gpt-4o"
+# provider = "copilot"
+# temperature = 0.4
+
+[models.cli]
+# model = "gpt-4.1"
+# provider = "openai"
+# temperature = 0.6
+
 [provider]
 name = "openai"                      # openai | copilot | ollama
 
diff --git a/docs/configuration.md b/docs/configuration.md
index 6239a4c..6db7a27 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -21,6 +21,29 @@ Environment overrides
   - `HEXAI_OPENAI_MODEL`, `HEXAI_OPENAI_BASE_URL`, `HEXAI_OPENAI_TEMPERATURE`
   - `HEXAI_COPILOT_MODEL`, `HEXAI_COPILOT_BASE_URL`, `HEXAI_COPILOT_TEMPERATURE`
   - `HEXAI_OLLAMA_MODEL`, `HEXAI_OLLAMA_BASE_URL`, `HEXAI_OLLAMA_TEMPERATURE`
+  - Per-surface overrides: `HEXAI_MODEL_COMPLETION`, `HEXAI_MODEL_CODE_ACTION`, `HEXAI_MODEL_CHAT`, `HEXAI_MODEL_CLI`
+  - Per-surface temperatures: `HEXAI_TEMPERATURE_COMPLETION`, `HEXAI_TEMPERATURE_CODE_ACTION`, `HEXAI_TEMPERATURE_CHAT`, `HEXAI_TEMPERATURE_CLI`
+
+Per-surface models
+
+- Use the `[models]` table in `config.toml` to tailor individual entry points (completion, code actions, chat, CLI) without changing the global provider default.
+- Each key accepts either a string (shortcut) or a table with `model` / `temperature` fields, e.g.:
+
+  ```toml
+  [models]
+  completion = "gpt-4.1-mini"
+
+  [models.code_action]
+  model = "gpt-4o"
+  provider = "copilot"
+  temperature = 0.4
+
+  [models.cli]
+  model = "gpt-4.1"
+  provider = "openai"
+  ```
+
+- When a per-surface value is omitted, Hexai falls back to the provider’s configured default. Temperatures inherit from `coding_temperature` unless explicitly set, and OpenAI `gpt-5*` models automatically raise an unspecified coding temperature to `1.0` for exploratory behavior. Provider overrides support `"openai"`, `"copilot"`, or `"ollama"` and read the matching credential variables.
 
 Runtime reloads
 
diff --git a/internal/appconfig/config.go b/internal/appconfig/config.go
index adf9b75..47abaaf 100644
--- a/internal/appconfig/config.go
+++ b/internal/appconfig/config.go
@@ -58,6 +58,20 @@ type App struct {
 	// Default temperature for Copilot requests (nil means use provider default)
 	CopilotTemperature *float64 `json:"copilot_temperature" toml:"copilot_temperature"`
 
+	// Per-surface model overrides (fall back to provider defaults when unset)
+	CompletionModel       string   `json:"completion_model" toml:"completion_model"`
+	CompletionTemperature *float64 `json:"completion_temperature" toml:"completion_temperature"`
+	CompletionProvider    string   `json:"completion_provider" toml:"completion_provider"`
+	CodeActionModel       string   `json:"code_action_model" toml:"code_action_model"`
+	CodeActionTemperature *float64 `json:"code_action_temperature" toml:"code_action_temperature"`
+	CodeActionProvider    string   `json:"code_action_provider" toml:"code_action_provider"`
+	ChatModel             string   `json:"chat_model" toml:"chat_model"`
+	ChatTemperature       *float64 `json:"chat_temperature" toml:"chat_temperature"`
+	ChatProvider          string   `json:"chat_provider" toml:"chat_provider"`
+	CLIModel              string   `json:"cli_model" toml:"cli_model"`
+	CLITemperature        *float64 `json:"cli_temperature" toml:"cli_temperature"`
+	CLIProvider           string   `json:"cli_provider" toml:"cli_provider"`
+
 	// Prompt templates (configured only via file; no env overrides)
 	// Completion/chat/code action/CLI prompt strings. See config.toml.example for placeholders.
 	// Completion
@@ -589,7 +603,7 @@ func loadFromFile(path string, logger *log.Logger) (*App, error) {
 		"copilot_model": {}, "copilot_base_url": {}, "copilot_temperature": {},
 	}
 	for k := range raw {
-		if _, isTable := map[string]struct{}{"general": {}, "logging": {}, "completion": {}, "triggers": {}, "inline": {}, "chat": {}, "provider": {}, "openai": {}, "copilot": {}, "ollama": {}, "prompts": {}}[k]; isTable {
+		if _, isTable := map[string]struct{}{"general": {}, "logging": {}, "completion": {}, "triggers": {}, "inline": {}, "chat": {}, "provider": {}, "models": {}, "openai": {}, "copilot": {}, "ollama": {}, "prompts": {}}[k]; isTable {
 			continue
 		}
 		if _, isLegacy := legacy[k]; isLegacy {
@@ -629,12 +643,170 @@ func loadFromFile(path string, logger *log.Logger) (*App, error) {
 			}
 		}
 	}
+	if m := parseSurfaceModels(raw, logger); m != nil {
+		tab.mergeSurfaceModels(m)
+	}
 	return &tab, nil
 }
 
+func parseSurfaceModels(raw map[string]any, logger *log.Logger) *App {
+	modelsRaw, ok := raw["models"]
+	if !ok {
+		return nil
+	}
+	table, ok := modelsRaw.(map[string]any)
+	if !ok {
+		if logger != nil {
+			logger.Printf("config: ignoring models section (expected table, got %T)", modelsRaw)
+		}
+		return nil
+	}
+	var out App
+	var any bool
+	if model, provider, temp, ok := decodeModelEntry(table["completion"], "models.completion", logger); ok {
+		if model != "" {
+			out.CompletionModel = model
+		}
+		if provider != "" {
+			out.CompletionProvider = provider
+		}
+		if temp != nil {
+			out.CompletionTemperature = temp
+		}
+		any = true
+	}
+	if model, provider, temp, ok := decodeModelEntry(table["code_action"], "models.code_action", logger); ok {
+		if model != "" {
+			out.CodeActionModel = model
+		}
+		if provider != "" {
+			out.CodeActionProvider = provider
+		}
+		if temp != nil {
+			out.CodeActionTemperature = temp
+		}
+		any = true
+	}
+	if model, provider, temp, ok := decodeModelEntry(table["chat"], "models.chat", logger); ok {
+		if model != "" {
+			out.ChatModel = model
+		}
+		if provider != "" {
+			out.ChatProvider = provider
+		}
+		if temp != nil {
+			out.ChatTemperature = temp
+		}
+		any = true
+	}
+	if model, provider, temp, ok := decodeModelEntry(table["cli"], "models.cli", logger); ok {
+		if model != "" {
+			out.CLIModel = model
+		}
+		if provider != "" {
+			out.CLIProvider = provider
+		}
+		if temp != nil {
+			out.CLITemperature = temp
+		}
+		any = true
+	}
+	if !any {
+		return nil
+	}
+	return &out
+}
+
+func decodeModelEntry(raw any, path string, logger *log.Logger) (string, string, *float64, bool) {
+	if raw == nil {
+		return "", "", nil, false
+	}
+	switch v := raw.(type) {
+	case string:
+		model := strings.TrimSpace(v)
+		if model == "" {
+			return "", "", nil, false
+		}
+		return model, "", nil, true
+	case map[string]any:
+		model := ""
+		provider := ""
+		if m, ok := v["model"]; ok {
+			s, ok := m.(string)
+			if !ok {
+				if logger != nil {
+					logger.Printf("config: %s.model must be a string", path)
+				}
+				return "", "", nil, false
+			}
+			model = strings.TrimSpace(s)
+		}
+		if pRaw, ok := v["provider"]; ok {
+			ps, ok := pRaw.(string)
+			if !ok {
+				if logger != nil {
+					logger.Printf("config: %s.provider must be a string", path)
+				}
+				return "", "", nil, false
+			}
+			provider = strings.TrimSpace(ps)
+		}
+		var tempPtr *float64
+		if tRaw, ok := v["temperature"]; ok {
+			parsed, ok := parseTemperatureValue(tRaw, path, logger)
+			if !ok {
+				return "", "", nil, false
+			}
+			tempPtr = parsed
+		}
+		if model == "" && tempPtr == nil && provider == "" {
+			return "", "", nil, false
+		}
+		return model, provider, tempPtr, true
+	default:
+		if logger != nil {
+			logger.Printf("config: %s must be a string or table, got %T", path, raw)
+		}
+		return "", "", nil, false
+	}
+}
+
+func parseTemperatureValue(raw any, path string, logger *log.Logger) (*float64, bool) {
+	switch v := raw.(type) {
+	case float64:
+		return floatPtr(v), true
+	case int64:
+		return floatPtr(float64(v)), true
+	case string:
+		s := strings.TrimSpace(v)
+		if s == "" {
+			return nil, true
+		}
+		f, err := strconv.ParseFloat(s, 64)
+		if err != nil {
+			if logger != nil {
+				logger.Printf("config: %s.temperature invalid: %v", path, err)
+			}
+			return nil, false
+		}
+		return floatPtr(f), true
+	default:
+		if logger != nil {
+			logger.Printf("config: %s.temperature must be numeric or string, got %T", path, raw)
+		}
+		return nil, false
+	}
+}
+
+func floatPtr(v float64) *float64 {
+	f := v
+	return &f
+}
+
 func (a *App) mergeWith(other *App) {
 	a.mergeBasics(other)
 	a.mergeProviderFields(other)
+	a.mergeSurfaceModels(other)
 	a.mergePrompts(other)
 }
 
@@ -687,6 +859,46 @@ func (a *App) mergeBasics(other *App) {
 	}
 }
 
+// mergeSurfaceModels copies per-surface model and temperature overrides.
+func (a *App) mergeSurfaceModels(other *App) {
+	if s := strings.TrimSpace(other.CompletionModel); s != "" {
+		a.CompletionModel = s
+	}
+	if other.CompletionTemperature != nil {
+		a.CompletionTemperature = other.CompletionTemperature
+	}
+	if s := strings.TrimSpace(other.CompletionProvider); s != "" {
+		a.CompletionProvider = s
+	}
+	if s := strings.TrimSpace(other.CodeActionModel); s != "" {
+		a.CodeActionModel = s
+	}
+	if other.CodeActionTemperature != nil {
+		a.CodeActionTemperature = other.CodeActionTemperature
+	}
+	if s := strings.TrimSpace(other.CodeActionProvider); s != "" {
+		a.CodeActionProvider = s
+	}
+	if s := strings.TrimSpace(other.ChatModel); s != "" {
+		a.ChatModel = s
+	}
+	if other.ChatTemperature != nil {
+		a.ChatTemperature = other.ChatTemperature
+	}
+	if s := strings.TrimSpace(other.ChatProvider); s != "" {
+		a.ChatProvider = s
+	}
+	if s := strings.TrimSpace(other.CLIModel); s != "" {
+		a.CLIModel = s
+	}
+	if other.CLITemperature != nil {
+		a.CLITemperature = other.CLITemperature
+	}
+	if s := strings.TrimSpace(other.CLIProvider); s != "" {
+		a.CLIProvider = s
+	}
+}
+
 // mergePrompts copies non-empty prompt templates from other.
 func (a *App) mergePrompts(other *App) {
 	// Completion
@@ -1050,6 +1262,56 @@ func loadFromEnv(logger *log.Logger) *App {
 		any = true
 	}
 
+	// Per-surface overrides
+	if s := getenv("HEXAI_MODEL_COMPLETION"); s != "" {
+		out.CompletionModel = s
+		any = true
+	}
+	if f, ok := parseFloatPtr("HEXAI_TEMPERATURE_COMPLETION"); ok {
+		out.CompletionTemperature = f
+		any = true
+	}
+	if s := getenv("HEXAI_PROVIDER_COMPLETION"); s != "" {
+		out.CompletionProvider = s
+		any = true
+	}
+	if s := getenv("HEXAI_MODEL_CODE_ACTION"); s != "" {
+		out.CodeActionModel = s
+		any = true
+	}
+	if f, ok := parseFloatPtr("HEXAI_TEMPERATURE_CODE_ACTION"); ok {
+		out.CodeActionTemperature = f
+		any = true
+	}
+	if s := getenv("HEXAI_PROVIDER_CODE_ACTION"); s != "" {
+		out.CodeActionProvider = s
+		any = true
+	}
+	if s := getenv("HEXAI_MODEL_CHAT"); s != "" {
+		out.ChatModel = s
+		any = true
+	}
+	if f, ok := parseFloatPtr("HEXAI_TEMPERATURE_CHAT"); ok {
+		out.ChatTemperature = f
+		any = true
+	}
+	if s := getenv("HEXAI_PROVIDER_CHAT"); s != "" {
+		out.ChatProvider = s
+		any = true
+	}
+	if s := getenv("HEXAI_MODEL_CLI"); s != "" {
+		out.CLIModel = s
+		any = true
+	}
+	if f, ok := parseFloatPtr("HEXAI_TEMPERATURE_CLI"); ok {
+		out.CLITemperature = f
+		any = true
+	}
+	if s := getenv("HEXAI_PROVIDER_CLI"); s != "" {
+		out.CLIProvider = s
+		any = true
+	}
+
 	if !any {
 		return nil
 	}
diff --git a/internal/appconfig/config_env_model_test.go b/internal/appconfig/config_env_model_test.go
index 2db2bb5..f34416d 100644
--- a/internal/appconfig/config_env_model_test.go
+++ b/internal/appconfig/config_env_model_test.go
@@ -1,37 +1,65 @@
 package appconfig
 
 import (
-    "log"
-    "os"
-    "testing"
+	"log"
+	"os"
+	"testing"
 )
 
 // Test that HEXAI_MODEL applies to provider model fields and that
 // provider-specific envs take precedence when both are set.
 func TestEnv_GenericModelOverrideAndPrecedence(t *testing.T) {
-    t.Setenv("HEXAI_MODEL", "gpt-5-codex")
-    t.Setenv("HEXAI_PROVIDER", "openai")
-    // No provider-specific env set yet: HEXAI_MODEL should flow into OpenAIModel
-    cfg := Load(log.New(os.Stderr, "test ", 0))
-    if cfg.OpenAIModel != "gpt-5-codex" {
-        t.Fatalf("expected OpenAIModel=gpt-5-codex via HEXAI_MODEL, got %q", cfg.OpenAIModel)
-    }
+	t.Setenv("HEXAI_MODEL", "gpt-5-codex")
+	t.Setenv("HEXAI_PROVIDER", "openai")
+	// No provider-specific env set yet: HEXAI_MODEL should flow into OpenAIModel
+	cfg := Load(log.New(os.Stderr, "test ", 0))
+	if cfg.OpenAIModel != "gpt-5-codex" {
+		t.Fatalf("expected OpenAIModel=gpt-5-codex via HEXAI_MODEL, got %q", cfg.OpenAIModel)
+	}
 
-    // Now set a provider-specific model; it should win over HEXAI_MODEL
-    t.Setenv("HEXAI_OPENAI_MODEL", "gpt-5-thinking")
-    cfg2 := Load(log.New(os.Stderr, "test ", 0))
-    if cfg2.OpenAIModel != "gpt-5-thinking" {
-        t.Fatalf("expected OpenAIModel from HEXAI_OPENAI_MODEL to win, got %q", cfg2.OpenAIModel)
-    }
+	// Now set a provider-specific model; it should win over HEXAI_MODEL
+	t.Setenv("HEXAI_OPENAI_MODEL", "gpt-5-thinking")
+	cfg2 := Load(log.New(os.Stderr, "test ", 0))
+	if cfg2.OpenAIModel != "gpt-5-thinking" {
+		t.Fatalf("expected OpenAIModel from HEXAI_OPENAI_MODEL to win, got %q", cfg2.OpenAIModel)
+	}
 }
 
 // Test that HEXAI_MODEL_FORCE overrides provider-specific envs (used by CLI --model).
 func TestEnv_ModelForce_OverridesProviderSpecific(t *testing.T) {
-    t.Setenv("HEXAI_OPENAI_MODEL", "gpt-5-main")
-    t.Setenv("HEXAI_MODEL_FORCE", "gpt-5-codex")
-    t.Setenv("HEXAI_PROVIDER", "openai")
-    cfg := Load(log.New(os.Stderr, "test ", 0))
-    if cfg.OpenAIModel != "gpt-5-codex" {
-        t.Fatalf("expected OpenAIModel forced to gpt-5-codex, got %q", cfg.OpenAIModel)
-    }
+	t.Setenv("HEXAI_OPENAI_MODEL", "gpt-5-main")
+	t.Setenv("HEXAI_MODEL_FORCE", "gpt-5-codex")
+	t.Setenv("HEXAI_PROVIDER", "openai")
+	cfg := Load(log.New(os.Stderr, "test ", 0))
+	if cfg.OpenAIModel != "gpt-5-codex" {
+		t.Fatalf("expected OpenAIModel forced to gpt-5-codex, got %q", cfg.OpenAIModel)
+	}
+}
+
+func TestEnv_SurfaceModelOverrides(t *testing.T) {
+	t.Setenv("HEXAI_MODEL_COMPLETION", "gpt-c")
+	t.Setenv("HEXAI_TEMPERATURE_COMPLETION", "0.44")
+	t.Setenv("HEXAI_PROVIDER_COMPLETION", "copilot")
+	t.Setenv("HEXAI_MODEL_CLI", "gpt-cli")
+	t.Setenv("HEXAI_TEMPERATURE_CLI", "0.22")
+	t.Setenv("HEXAI_PROVIDER_CLI", "ollama")
+	cfg := Load(log.New(os.Stderr, "test ", 0))
+	if cfg.CompletionModel != "gpt-c" {
+		t.Fatalf("expected completion model override, got %q", cfg.CompletionModel)
+	}
+	if cfg.CompletionTemperature == nil || *cfg.CompletionTemperature != 0.44 {
+		t.Fatalf("expected completion temperature override, got %v", cfg.CompletionTemperature)
+	}
+	if cfg.CompletionProvider != "copilot" {
+		t.Fatalf("expected completion provider override, got %q", cfg.CompletionProvider)
+	}
+	if cfg.CLIModel != "gpt-cli" {
+		t.Fatalf("expected cli model override, got %q", cfg.CLIModel)
+	}
+	if cfg.CLITemperature == nil || *cfg.CLITemperature != 0.22 {
+		t.Fatalf("expected cli temperature override, got %v", cfg.CLITemperature)
+	}
+	if cfg.CLIProvider != "ollama" {
+		t.Fatalf("expected cli provider override, got %q", cfg.CLIProvider)
+	}
 }
diff --git a/internal/appconfig/config_test.go b/internal/appconfig/config_test.go
index b03137e..ea68305 100644
--- a/internal/appconfig/config_test.go
+++ b/internal/appconfig/config_test.go
@@ -88,6 +88,24 @@ completion_throttle_ms = 300
 [triggers]
 trigger_characters = [".", ":"]
 
+[models.completion]
+model = "gpt-file-complete"
+provider = "openai"
+
+[models.code_action]
+model = "gpt-file-action"
+temperature = 0.45
+provider = "copilot"
+
+[models.chat]
+model = "gpt-file-chat"
+provider = "openai"
+
+[models.cli]
+model = "gpt-file-cli"
+temperature = 0.15
+provider = "ollama"
+
 [provider]
 name = "openai"
 
@@ -107,6 +125,10 @@ model = "ghost"
 temperature = 0.0
 `)
 
+	if _, err := loadFromFile(cfgPath, newLogger()); err != nil {
+		t.Fatalf("loadFromFile: %v", err)
+	}
+
 	// Env overrides take precedence
 	withEnv(t, "HEXAI_MAX_TOKENS", "321")
 	withEnv(t, "HEXAI_CONTEXT_MODE", "always-full")
@@ -128,6 +150,18 @@ temperature = 0.0
 	withEnv(t, "HEXAI_COPILOT_BASE_URL", "http://copilot-override")
 	withEnv(t, "HEXAI_COPILOT_MODEL", "ghost-override")
 	withEnv(t, "HEXAI_COPILOT_TEMPERATURE", "0.3")
+	withEnv(t, "HEXAI_MODEL_COMPLETION", "env-completion")
+	withEnv(t, "HEXAI_TEMPERATURE_COMPLETION", "0.33")
+	withEnv(t, "HEXAI_PROVIDER_COMPLETION", "copilot")
+	withEnv(t, "HEXAI_MODEL_CODE_ACTION", "env-action")
+	withEnv(t, "HEXAI_TEMPERATURE_CODE_ACTION", "0.55")
+	withEnv(t, "HEXAI_PROVIDER_CODE_ACTION", "openai")
+	withEnv(t, "HEXAI_MODEL_CHAT", "env-chat")
+	withEnv(t, "HEXAI_TEMPERATURE_CHAT", "0.66")
+	withEnv(t, "HEXAI_PROVIDER_CHAT", "copilot")
+	withEnv(t, "HEXAI_MODEL_CLI", "env-cli")
+	withEnv(t, "HEXAI_TEMPERATURE_CLI", "0.77")
+	withEnv(t, "HEXAI_PROVIDER_CLI", "ollama")
 
 	logger := newLogger()
 	cfg := Load(logger)
@@ -158,11 +192,35 @@ temperature = 0.0
 	if cfg.CopilotBaseURL != "http://copilot-override" || cfg.CopilotModel != "ghost-override" || cfg.CopilotTemperature == nil || *cfg.CopilotTemperature != 0.3 {
 		t.Fatalf("copilot overrides not applied: %+v", cfg)
 	}
+	if cfg.CompletionModel != "env-completion" || cfg.CompletionTemperature == nil || *cfg.CompletionTemperature != 0.33 {
+		t.Fatalf("completion overrides not applied: model=%q temp=%v", cfg.CompletionModel, cfg.CompletionTemperature)
+	}
+	if cfg.CompletionProvider != "copilot" {
+		t.Fatalf("completion provider override not applied: %q", cfg.CompletionProvider)
+	}
+	if cfg.CodeActionModel != "env-action" || cfg.CodeActionTemperature == nil || *cfg.CodeActionTemperature != 0.55 {
+		t.Fatalf("code action overrides not applied: model=%q temp=%v", cfg.CodeActionModel, cfg.CodeActionTemperature)
+	}
+	if cfg.CodeActionProvider != "openai" {
+		t.Fatalf("code action provider override not applied: %q", cfg.CodeActionProvider)
+	}
+	if cfg.ChatModel != "env-chat" || cfg.ChatTemperature == nil || *cfg.ChatTemperature != 0.66 {
+		t.Fatalf("chat overrides not applied: model=%q temp=%v", cfg.ChatModel, cfg.ChatTemperature)
+	}
+	if cfg.ChatProvider != "copilot" {
+		t.Fatalf("chat provider override not applied: %q", cfg.ChatProvider)
+	}
+	if cfg.CLIModel != "env-cli" || cfg.CLITemperature == nil || *cfg.CLITemperature != 0.77 {
+		t.Fatalf("cli overrides not applied: model=%q temp=%v", cfg.CLIModel, cfg.CLITemperature)
+	}
+	if cfg.CLIProvider != "ollama" {
+		t.Fatalf("cli provider override not applied: %q", cfg.CLIProvider)
+	}
 
 	// Ensure file values would have applied absent env
 	// Spot-check: reset env and reload
 	for _, k := range []string{
-		"HEXAI_MAX_TOKENS", "HEXAI_CONTEXT_MODE", "HEXAI_CONTEXT_WINDOW_LINES", "HEXAI_MAX_CONTEXT_TOKENS", "HEXAI_LOG_PREVIEW_LIMIT", "HEXAI_CODING_TEMPERATURE", "HEXAI_MANUAL_INVOKE_MIN_PREFIX", "HEXAI_COMPLETION_DEBOUNCE_MS", "HEXAI_COMPLETION_THROTTLE_MS", "HEXAI_TRIGGER_CHARACTERS", "HEXAI_PROVIDER", "HEXAI_OPENAI_BASE_URL", "HEXAI_OPENAI_MODEL", "HEXAI_OPENAI_TEMPERATURE", "HEXAI_OLLAMA_BASE_URL", "HEXAI_OLLAMA_MODEL", "HEXAI_OLLAMA_TEMPERATURE", "HEXAI_COPILOT_BASE_URL", "HEXAI_COPILOT_MODEL", "HEXAI_COPILOT_TEMPERATURE",
+		"HEXAI_MAX_TOKENS", "HEXAI_CONTEXT_MODE", "HEXAI_CONTEXT_WINDOW_LINES", "HEXAI_MAX_CONTEXT_TOKENS", "HEXAI_LOG_PREVIEW_LIMIT", "HEXAI_CODING_TEMPERATURE", "HEXAI_MANUAL_INVOKE_MIN_PREFIX", "HEXAI_COMPLETION_DEBOUNCE_MS", "HEXAI_COMPLETION_THROTTLE_MS", "HEXAI_TRIGGER_CHARACTERS", "HEXAI_PROVIDER", "HEXAI_OPENAI_BASE_URL", "HEXAI_OPENAI_MODEL", "HEXAI_OPENAI_TEMPERATURE", "HEXAI_OLLAMA_BASE_URL", "HEXAI_OLLAMA_MODEL", "HEXAI_OLLAMA_TEMPERATURE", "HEXAI_COPILOT_BASE_URL", "HEXAI_COPILOT_MODEL", "HEXAI_COPILOT_TEMPERATURE", "HEXAI_MODEL_COMPLETION", "HEXAI_TEMPERATURE_COMPLETION", "HEXAI_MODEL_CODE_ACTION", "HEXAI_TEMPERATURE_CODE_ACTION", "HEXAI_MODEL_CHAT", "HEXAI_TEMPERATURE_CHAT", "HEXAI_MODEL_CLI", "HEXAI_TEMPERATURE_CLI", "HEXAI_PROVIDER_COMPLETION", "HEXAI_PROVIDER_CODE_ACTION", "HEXAI_PROVIDER_CHAT", "HEXAI_PROVIDER_CLI",
 	} {
 		t.Setenv(k, "")
 	}
@@ -176,6 +234,30 @@ temperature = 0.0
 	if cfg2.OpenAIBaseURL != "https://api.example" || cfg2.OpenAIModel != "gpt-x" || cfg2.OpenAITemperature == nil || *cfg2.OpenAITemperature != 0.0 {
 		t.Fatalf("file merge (openai) not applied: %+v", cfg2)
 	}
+	if cfg2.CompletionModel != "gpt-file-complete" || cfg2.CompletionTemperature != nil {
+		t.Fatalf("file merge (completion) not applied: %+v", cfg2)
+	}
+	if cfg2.CompletionProvider != "openai" {
+		t.Fatalf("file merge (completion provider) not applied: %q", cfg2.CompletionProvider)
+	}
+	if cfg2.CodeActionModel != "gpt-file-action" || cfg2.CodeActionTemperature == nil || *cfg2.CodeActionTemperature != 0.45 {
+		t.Fatalf("file merge (code action) not applied: %+v", cfg2)
+	}
+	if cfg2.CodeActionProvider != "copilot" {
+		t.Fatalf("file merge (code action provider) not applied: %q", cfg2.CodeActionProvider)
+	}
+	if cfg2.ChatModel != "gpt-file-chat" || cfg2.ChatTemperature != nil {
+		t.Fatalf("file merge (chat) not applied: %+v", cfg2)
+	}
+	if cfg2.ChatProvider != "openai" {
+		t.Fatalf("file merge (chat provider) not applied: %q", cfg2.ChatProvider)
+	}
+	if cfg2.CLIModel != "gpt-file-cli" || cfg2.CLITemperature == nil || *cfg2.CLITemperature != 0.15 {
+		t.Fatalf("file merge (cli) not applied: %+v", cfg2)
+	}
+	if cfg2.CLIProvider != "ollama" {
+		t.Fatalf("file merge (cli provider) not applied: %q", cfg2.CLIProvider)
+	}
 }
 
 func TestGetConfigPath_XDG(t *testing.T) {
diff --git a/internal/hexaiaction/prompts.go b/internal/hexaiaction/prompts.go
index 207302e..47dadbf 100644
--- a/internal/hexaiaction/prompts.go
+++ b/internal/hexaiaction/prompts.go
@@ -25,6 +25,11 @@ type chatDoer interface {
 
 type providerNamer interface{ Name() string }
 
+type requestArgs struct {
+	model   string
+	options []llm.RequestOption
+}
+
 func providerOf(c any) string {
 	if n, ok := c.(providerNamer); ok {
 		return n.Name()
@@ -32,6 +37,42 @@ func providerOf(c any) string {
 	return "llm"
 }
 
+func canonicalProvider(name string) string {
+	p := strings.ToLower(strings.TrimSpace(name))
+	if p == "" {
+		return "openai"
+	}
+	return p
+}
+
+func defaultModelForProvider(cfg appconfig.App, provider string) string {
+	switch provider {
+	case "ollama":
+		return cfg.OllamaModel
+	case "copilot":
+		return cfg.CopilotModel
+	default:
+		return cfg.OpenAIModel
+	}
+}
+
+func selectActionTemperature(cfg appconfig.App, provider, model string) (float64, bool) {
+	if cfg.CodeActionTemperature != nil {
+		return *cfg.CodeActionTemperature, true
+	}
+	if cfg.CodingTemperature != nil {
+		temp := *cfg.CodingTemperature
+		if provider == "openai" && strings.HasPrefix(strings.ToLower(model), "gpt-5") && temp == 0.2 {
+			temp = 1.0
+		}
+		return temp, true
+	}
+	if provider == "openai" && strings.HasPrefix(strings.ToLower(model), "gpt-5") {
+		return 1.0, true
+	}
+	return 0, false
+}
+
 func runRewrite(ctx context.Context, cfg appconfig.App, client chatDoer, instruction, selection string) (string, error) {
 	sys := cfg.PromptCodeActionRewriteSystem
 	user := Render(cfg.PromptCodeActionRewriteUser, map[string]string{"instruction": instruction, "selection": selection})
@@ -118,9 +159,9 @@ func runOnce(ctx context.Context, client chatDoer, sys, user string) (string, er
 	return out, nil
 }
 
-func runOnceWithOpts(ctx context.Context, client chatDoer, sys, user string, opts []llm.RequestOption) (string, error) {
+func runOnceWithOpts(ctx context.Context, client chatDoer, sys, user string, req requestArgs) (string, error) {
 	msgs := []llm.Message{{Role: "system", Content: sys}, {Role: "user", Content: user}}
-	txt, err := client.Chat(ctx, msgs, opts...)
+	txt, err := client.Chat(ctx, msgs, req.options...)
 	if err != nil {
 		return "", err
 	}
@@ -131,7 +172,11 @@ func runOnceWithOpts(ctx context.Context, client chatDoer, sys, user string, opt
 		sent += len(m.Content)
 	}
 	recv := len(out)
-	_ = stats.Update(ctx, providerOf(client), client.DefaultModel(), sent, recv)
+	model := strings.TrimSpace(req.model)
+	if model == "" {
+		model = client.DefaultModel()
+	}
+	_ = stats.Update(ctx, providerOf(client), model, sent, recv)
 	if snap, err := stats.TakeSnapshot(); err == nil {
 		minsWin := snap.Window.Minutes()
 		if minsWin <= 0 {
@@ -139,30 +184,39 @@ func runOnceWithOpts(ctx context.Context, client chatDoer, sys, user string, opt
 		}
 		scopeReqs := int64(0)
 		if pe, ok := snap.Providers[providerOf(client)]; ok {
-			if mc, ok2 := pe.Models[client.DefaultModel()]; ok2 {
+			if mc, ok2 := pe.Models[model]; ok2 {
 				scopeReqs = mc.Reqs
 			}
 		}
 		scopeRPM := float64(scopeReqs) / minsWin
-		_ = tmux.SetStatus(tmux.FormatGlobalStatusColored(snap.Global.Reqs, snap.RPM, snap.Global.Sent, snap.Global.Recv, providerOf(client), client.DefaultModel(), scopeRPM, scopeReqs, snap.Window))
+		_ = tmux.SetStatus(tmux.FormatGlobalStatusColored(snap.Global.Reqs, snap.RPM, snap.Global.Sent, snap.Global.Recv, providerOf(client), model, scopeRPM, scopeReqs, snap.Window))
 	}
 	return out, nil
 }
 
 // reqOptsFrom builds LLM request options similar to LSP behavior.
-func reqOptsFrom(cfg appconfig.App) []llm.RequestOption {
-	opts := []llm.RequestOption{llm.WithMaxTokens(cfg.MaxTokens)}
-	// Apply temperature, with special-case for gpt-5 (default temp must be 1.0)
-	if cfg.CodingTemperature != nil {
-		temp := *cfg.CodingTemperature
-		prov := strings.ToLower(strings.TrimSpace(cfg.Provider))
-		model := strings.ToLower(strings.TrimSpace(cfg.OpenAIModel))
-		if prov == "openai" && strings.HasPrefix(model, "gpt-5") {
-			temp = 1.0
-		}
+func reqOptsFrom(cfg appconfig.App) requestArgs {
+	opts := make([]llm.RequestOption, 0, 3)
+	if cfg.MaxTokens > 0 {
+		opts = append(opts, llm.WithMaxTokens(cfg.MaxTokens))
+	}
+	provider := canonicalProvider(cfg.Provider)
+	if strings.TrimSpace(cfg.CodeActionProvider) != "" {
+		provider = canonicalProvider(cfg.CodeActionProvider)
+	}
+	override := strings.TrimSpace(cfg.CodeActionModel)
+	fallback := strings.TrimSpace(defaultModelForProvider(cfg, provider))
+	effective := override
+	if effective == "" {
+		effective = fallback
+	}
+	if override != "" {
+		opts = append(opts, llm.WithModel(override))
+	}
+	if temp, ok := selectActionTemperature(cfg, provider, effective); ok {
 		opts = append(opts, llm.WithTemperature(temp))
 	}
-	return opts
+	return requestArgs{model: effective, options: opts}
 }
 
 // Timeout helpers to mirror LSP behavior.
diff --git a/internal/hexaiaction/prompts_more_test.go b/internal/hexaiaction/prompts_more_test.go
index 9f5d6cb..97d3979 100644
--- a/internal/hexaiaction/prompts_more_test.go
+++ b/internal/hexaiaction/prompts_more_test.go
@@ -5,6 +5,7 @@ import (
 	"strings"
 	"testing"
 
+	"codeberg.org/snonux/hexai/internal/appconfig"
 	"codeberg.org/snonux/hexai/internal/llm"
 )
 
@@ -15,6 +16,11 @@ func (d simpleDoer) Chat(_ context.Context, _ []llm.Message, _ ...llm.RequestOpt
 }
 func (d simpleDoer) DefaultModel() string { return "m" }
 
+func ptrFloat(v float64) *float64 {
+	x := v
+	return &x
+}
+
 func TestRunOnce_StripsFences(t *testing.T) {
 	got, err := runOnce(context.Background(), simpleDoer{"```\nok\n```"}, "SYS", "USER")
 	if err != nil {
@@ -24,3 +30,30 @@ func TestRunOnce_StripsFences(t *testing.T) {
 		t.Fatalf("got %q", got)
 	}
 }
+
+func TestReqOptsFrom_Override(t *testing.T) {
+	cfg := appconfig.App{MaxTokens: 123, CodeActionModel: "override", CodeActionTemperature: ptrFloat(0.6), Provider: "openai", CodeActionProvider: "copilot", CopilotModel: "gpt-4o"}
+	req := reqOptsFrom(cfg)
+	if req.model != "override" {
+		t.Fatalf("expected override model, got %q", req.model)
+	}
+	var opts llm.Options
+	for _, o := range req.options {
+		o(&opts)
+	}
+	if opts.MaxTokens != 123 || opts.Model != "override" || opts.Temperature != 0.6 {
+		t.Fatalf("unexpected options: %+v", opts)
+	}
+}
+
+func TestReqOptsFrom_Gpt5Temp(t *testing.T) {
+	cfg := appconfig.App{Provider: "openai",