codex: rebase custom model aliases onto main

Author: friel-openai

codex-rs/core/src/codex_tests.rs

@@ -61,6 +61,7 @@ use opentelemetry::trace::TraceContextExt;
 use opentelemetry::trace::TraceId;
 use opentelemetry::trace::TracerProvider as _;
 use opentelemetry_sdk::trace::SdkTracerProvider;
+use std::collections::HashMap;
 use std::path::Path;
 use std::time::Duration;
 use tokio::time::sleep;
@@ -1892,6 +1893,7 @@ async fn session_new_fails_when_zsh_fork_enabled_without_zsh_path() {
         config.codex_home.clone(),
         auth_manager.clone(),
         None,
+        HashMap::new(),
         CollaborationModesConfig::default(),
     ));
     let model = ModelsManager::get_model_offline_for_tests(config.model.as_deref());
@@ -1978,6 +1980,7 @@ pub(crate) async fn make_session_and_context() -> (Session, TurnContext) {
         config.codex_home.clone(),
         auth_manager.clone(),
         None,
+        HashMap::new(),
         CollaborationModesConfig::default(),
     ));
     let agent_control = AgentControl::default();
@@ -2383,6 +2386,7 @@ pub(crate) async fn make_session_and_context_with_dynamic_tools_and_rx(
         config.codex_home.clone(),
         auth_manager.clone(),
         None,
+        HashMap::new(),
         CollaborationModesConfig::default(),
     ));
     let agent_control = AgentControl::default();

codex-rs/core/src/config/config_tests.rs

@@ -2647,6 +2647,7 @@ fn test_precedence_fixture_with_o3_profile() -> std::io::Result<()> {
             review_model: None,
             model_context_window: None,
             model_auto_compact_token_limit: None,
+            custom_models: HashMap::new(),
             service_tier: None,
             model_provider_id: "openai".to_string(),
             model_provider: fixture.openai_provider.clone(),
@@ -2776,6 +2777,7 @@ fn test_precedence_fixture_with_gpt3_profile() -> std::io::Result<()> {
         review_model: None,
         model_context_window: None,
         model_auto_compact_token_limit: None,
+        custom_models: HashMap::new(),
         service_tier: None,
         model_provider_id: "openai-custom".to_string(),
         model_provider: fixture.openai_custom_provider.clone(),
@@ -2903,6 +2905,7 @@ fn test_precedence_fixture_with_zdr_profile() -> std::io::Result<()> {
         review_model: None,
         model_context_window: None,
         model_auto_compact_token_limit: None,
+        custom_models: HashMap::new(),
         service_tier: None,
         model_provider_id: "openai".to_string(),
         model_provider: fixture.openai_provider.clone(),
@@ -3016,6 +3019,7 @@ fn test_precedence_fixture_with_gpt5_profile() -> std::io::Result<()> {
         review_model: None,
         model_context_window: None,
         model_auto_compact_token_limit: None,
+        custom_models: HashMap::new(),
         service_tier: None,
         model_provider_id: "openai".to_string(),
         model_provider: fixture.openai_provider.clone(),

codex-rs/core/src/config/mod.rs

@@ -150,6 +150,12 @@ pub(crate) fn test_config() -> Config {
     .expect("load default test config")
 }
 
+impl Config {
+    pub(crate) fn custom_model_alias(&self, alias: &str) -> Option<&CustomModelConfig> {
+        self.custom_models.get(alias)
+    }
+}
+
 /// Application configuration loaded from disk and merged with overrides.
 #[derive(Debug, Clone, PartialEq)]
 pub struct Permissions {
@@ -343,6 +349,9 @@ pub struct Config {
     /// Combined provider map (defaults merged with user-defined overrides).
     pub model_providers: HashMap<String, ModelProviderInfo>,
 
+    /// User-defined model aliases shown in the picker.
+    pub custom_models: HashMap<String, CustomModelConfig>,
+
     /// Maximum number of bytes to include from an AGENTS.md project doc file.
     pub project_doc_max_bytes: usize,
 
@@ -1117,6 +1126,10 @@ pub struct ConfigToml {
     #[serde(default)]
     pub model_providers: HashMap<String, ModelProviderInfo>,
 
+    /// User-defined model aliases that can override model context settings.
+    #[serde(default)]
+    pub custom_models: Vec<CustomModelToml>,
+
     /// Maximum number of bytes to include from an AGENTS.md project doc file.
     pub project_doc_max_bytes: Option<usize>,
 
@@ -1351,6 +1364,29 @@ pub struct RealtimeAudioToml {
     pub speaker: Option<String>,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct CustomModelConfig {
+    /// Provider-facing model slug used on API requests.
+    pub model: String,
+    /// Optional context window override applied when this alias is selected.
+    pub model_context_window: Option<i64>,
+    /// Optional auto-compaction token limit override applied when this alias is selected.
+    pub model_auto_compact_token_limit: Option<i64>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, Default, PartialEq, Eq, JsonSchema)]
+#[schemars(deny_unknown_fields)]
+pub struct CustomModelToml {
+    /// User-facing alias shown in the model picker.
+    pub name: String,
+    /// Provider-facing model slug used on API requests.
+    pub model: String,
+    /// Optional context window override applied when this alias is selected.
+    pub model_context_window: Option<i64>,
+    /// Optional auto-compaction token limit override applied when this alias is selected.
+    pub model_auto_compact_token_limit: Option<i64>,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, Default, PartialEq, JsonSchema)]
 #[schemars(deny_unknown_fields)]
 pub struct ToolsToml {
@@ -1842,6 +1878,24 @@ impl Config {
         for (key, provider) in cfg.model_providers.into_iter() {
             model_providers.entry(key).or_insert(provider);
         }
+        let mut custom_models = HashMap::new();
+        for custom in cfg.custom_models {
+            let alias = custom.name;
+            if custom_models.contains_key(&alias) {
+                return Err(std::io::Error::new(
+                    ErrorKind::InvalidInput,
+                    format!("duplicate custom model alias: {alias}"),
+                ));
+            }
+            custom_models.insert(
+                alias,
+                CustomModelConfig {
+                    model: custom.model,
+                    model_context_window: custom.model_context_window,
+                    model_auto_compact_token_limit: custom.model_auto_compact_token_limit,
+                },
+            );
+        }
 
         let model_provider_id = model_provider
             .or(config_profile.model_provider)
@@ -2157,6 +2211,7 @@ impl Config {
             mcp_oauth_callback_port: cfg.mcp_oauth_callback_port,
             mcp_oauth_callback_url: cfg.mcp_oauth_callback_url.clone(),
             model_providers,
+            custom_models,
             project_doc_max_bytes: cfg.project_doc_max_bytes.unwrap_or(PROJECT_DOC_MAX_BYTES),
             project_doc_fallback_filenames: cfg
                 .project_doc_fallback_filenames