diff --git a/lib/crates/fabro-model/src/catalog.rs b/lib/crates/fabro-model/src/catalog.rs
index 5877bd5f2..69790f96d 100644
--- a/lib/crates/fabro-model/src/catalog.rs
+++ b/lib/crates/fabro-model/src/catalog.rs
@@ -3144,6 +3144,42 @@ enabled = true
         assert_eq!(selected.model, "claude-fable-5");
     }
 
+    #[test]
+    fn every_legacy_builtin_identifier_targets_an_existing_offering() {
+        let catalog = Catalog::from_builtin_with_overrides(&minimal_settings(
+            r"
+[providers.bedrock]
+enabled = true
+
+[providers.bedrock-openai]
+enabled = true
+
+[providers.openrouter]
+enabled = true
+",
+        ))
+        .expect("all providers referenced by the legacy table should build");
+
+        for (legacy_id, provider_id, canonical_id) in LEGACY_BUILTIN_MODEL_IDENTIFIERS {
+            let provider = ProviderId::new(*provider_id);
+            let model = catalog
+                .resolve_on_provider(&provider, legacy_id)
+                .unwrap_or_else(|error| {
+                    panic!(
+                        "legacy identifier '{legacy_id}' should resolve on '{provider}': {error}"
+                    )
+                });
+
+            assert_eq!(model.provider, provider, "{legacy_id}");
+            assert_eq!(model.id, *canonical_id, "{legacy_id}");
+            assert_eq!(
+                legacy_builtin_model(legacy_id),
+                Some((provider, ModelId::new(*canonical_id))),
+                "{legacy_id}"
+            );
+        }
+    }
+
     #[test]
     fn builtin_openrouter_includes_glm_5_2_when_enabled() {
         let catalog = Catalog::from_builtin_with_overrides(&minimal_settings(
@@ -5118,6 +5154,61 @@ reasoning = false
         );
     }
 
+    #[test]
+    fn effective_agent_profile_is_scoped_by_provider_for_shared_model_id() {
+        let layer = minimal_settings(
+            r#"
+[providers.one]
+display_name = "One"
+adapter = "openai"
+agent_profile = "openai"
+
+[providers.one.models.shared]
+display_name = "Shared on One"
+family = "test"
+default = true
+
+[providers.one.models.shared.limits]
+context_window = 1000
+
+[providers.one.models.shared.features]
+tools = false
+vision = false
+reasoning = false
+
+[providers.two]
+display_name = "Two"
+adapter = "openai"
+agent_profile = "anthropic"
+
+[providers.two.models.shared]
+display_name = "Shared on Two"
+family = "test"
+default = true
+agent_profile = "gemini"
+
+[providers.two.models.shared.limits]
+context_window = 1000
+
+[providers.two.models.shared.features]
+tools = false
+vision = false
+reasoning = false
+"#,
+        );
+
+        let catalog = Catalog::from_settings(&layer).unwrap();
+
+        assert_eq!(
+            catalog.effective_agent_profile(&ProviderId::new("one"), Some("shared")),
+            Some(AgentProfileKind::OpenAi)
+        );
+        assert_eq!(
+            catalog.effective_agent_profile(&ProviderId::new("two"), Some("shared")),
+            Some(AgentProfileKind::Gemini)
+        );
+    }
+
     #[test]
     fn omitted_agent_profile_uses_adapter_default() {
         let layer = minimal_settings(
diff --git a/lib/crates/fabro-server/src/server/tests.rs b/lib/crates/fabro-server/src/server/tests.rs
index 9ecdabcae..7aafcec03 100644
--- a/lib/crates/fabro-server/src/server/tests.rs
+++ b/lib/crates/fabro-server/src/server/tests.rs
@@ -13785,7 +13785,7 @@ async fn get_aggregate_billing_saturates_total_cost_across_models() {
             agg.by_model.insert(
                 ModelRef {
                     provider: ProviderId::openai(),
-                    model_id: model_id.to_string(),
+                    model_id: model_id.into(),
                     speed:    None,
                 },
                 ModelBillingTotals {
diff --git a/lib/crates/fabro-types/src/run_event/session.rs b/lib/crates/fabro-types/src/run_event/session.rs
index 504d4f653..78321afa4 100644
--- a/lib/crates/fabro-types/src/run_event/session.rs
+++ b/lib/crates/fabro-types/src/run_event/session.rs
@@ -110,3 +110,22 @@ pub struct RunSessionTurnInterruptedProps {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub error:   Option<String>,
 }
+
+#[cfg(test)]
+mod tests {
+    use serde_json::json;
+
+    use super::RunSessionCreatedProps;
+
+    #[test]
+    fn session_created_deserializes_legacy_payload_without_provider() {
+        let props: RunSessionCreatedProps = serde_json::from_value(json!({
+            "title": "Legacy session",
+            "model": "gpt-5.4"
+        }))
+        .unwrap();
+
+        assert_eq!(props.model.as_deref(), Some("gpt-5.4"));
+        assert_eq!(props.provider, None);
+    }
+}
diff --git a/lib/crates/fabro-types/src/session.rs b/lib/crates/fabro-types/src/session.rs
index eaad05181..b825338d9 100644
--- a/lib/crates/fabro-types/src/session.rs
+++ b/lib/crates/fabro-types/src/session.rs
@@ -188,13 +188,33 @@ impl SessionMessage {
 
 #[cfg(test)]
 mod tests {
+    use chrono::Utc;
     use serde_json::json;
 
-    use super::SessionStatus;
+    use super::{SessionId, SessionRecord, SessionStatus};
+    use crate::fixtures;
 
     #[test]
     fn session_status_rejects_removed_terminal_states() {
         assert!(serde_json::from_value::<SessionStatus>(json!("closed")).is_err());
         assert!(serde_json::from_value::<SessionStatus>(json!("deleted")).is_err());
     }
+
+    #[test]
+    fn session_record_deserializes_legacy_json_without_provider() {
+        let mut value = serde_json::to_value(SessionRecord::new(
+            SessionId::new(),
+            fixtures::RUN_1,
+            Utc::now(),
+        ))
+        .unwrap();
+        value
+            .as_object_mut()
+            .expect("session record should serialize as an object")
+            .remove("provider");
+
+        let record: SessionRecord = serde_json::from_value(value).unwrap();
+
+        assert_eq!(record.provider, None);
+    }
 }
diff --git a/lib/crates/fabro-workflow/src/event/convert.rs b/lib/crates/fabro-workflow/src/event/convert.rs
index b2ba1d715..528371880 100644
--- a/lib/crates/fabro-workflow/src/event/convert.rs
+++ b/lib/crates/fabro-workflow/src/event/convert.rs
@@ -2184,7 +2184,7 @@ mod tests {
                 text:            "ok".to_string(),
                 model:           ModelRef {
                     provider: ProviderId::new("openrouter"),
-                    model_id: "openai/gpt-5.4".to_string(),
+                    model_id: "openai/gpt-5.4".into(),
                     speed:    None,
                 },
                 usage:           LlmTokenCounts {
diff --git a/lib/crates/fabro-workflow/src/handler/llm/api.rs b/lib/crates/fabro-workflow/src/handler/llm/api.rs
index 573542d9f..4e60dfbff 100644
--- a/lib/crates/fabro-workflow/src/handler/llm/api.rs
+++ b/lib/crates/fabro-workflow/src/handler/llm/api.rs
@@ -2624,6 +2624,33 @@ reasoning = false
         assert_eq!(provider.profile_kind, AgentProfileKind::Anthropic);
     }
 
+    #[test]
+    fn api_backend_preserves_default_provider_for_legacy_model_identifier() {
+        let settings: LlmCatalogSettings = toml::from_str(
+            r"
+[providers.openrouter]
+enabled = true
+",
+        )
+        .unwrap();
+        let catalog = Arc::new(Catalog::from_builtin_with_overrides(&settings).unwrap());
+        let backend = AgentApiBackend::new_with_catalog(
+            "openai/gpt-5.4".to_string(),
+            ProviderId::from("openrouter"),
+            Vec::new(),
+            Arc::new(EnvCredentialSource::new()),
+            SteeringHub::for_tests(),
+            catalog,
+        );
+
+        let provider = backend
+            .resolve_provider_context("openai/gpt-5.4", None)
+            .unwrap();
+
+        assert_eq!(provider.provider_id, ProviderId::from("openrouter"));
+        assert_eq!(provider.profile_kind, AgentProfileKind::OpenAi);
+    }
+
     #[test]
     fn run_model_controls_apply_when_node_omits_controls() {
         let backend = AgentApiBackend::new_from_env(
diff --git a/lib/crates/fabro-workflow/src/handler/llm/routing.rs b/lib/crates/fabro-workflow/src/handler/llm/routing.rs
index 0bb05b216..b7d499b8c 100644
--- a/lib/crates/fabro-workflow/src/handler/llm/routing.rs
+++ b/lib/crates/fabro-workflow/src/handler/llm/routing.rs
@@ -58,6 +58,11 @@ pub(crate) fn resolve_provider_context(
             })?
             .id
             .clone()
+    } else if catalog
+        .get_on_provider(default_provider_id, model)
+        .is_some()
+    {
+        default_provider_id.clone()
     } else {
         match catalog.select(model, None, &catalog.all_provider_ids()) {
             Ok(model) => model.provider.clone(),
diff --git a/lib/crates/fabro-workflow/src/operations/create.rs b/lib/crates/fabro-workflow/src/operations/create.rs
index 488bb5c74..144cf5976 100644
--- a/lib/crates/fabro-workflow/src/operations/create.rs
+++ b/lib/crates/fabro-workflow/src/operations/create.rs
@@ -1462,11 +1462,11 @@ reasoning = false
     }
 
     #[tokio::test]
-    async fn create_materializes_shared_alias_for_ready_provider_snapshot_and_pin() {
-        const ALIAS_DOT: &str = r#"digraph Test {
+    async fn create_materializes_portable_selectors_for_ready_provider_snapshot_and_pin() {
+        const MODEL_DOT: &str = r#"digraph Test {
             graph [goal="Test"]
             start [shape=Mdiamond]
-            work [prompt="Do work", model="gpt-56-sol"]
+            work [prompt="Do work", model="MODEL_SELECTOR"]
             exit [shape=Msquare]
             start -> work -> exit
         }"#;
@@ -1490,65 +1490,94 @@ reasoning = false
             ),
         ];
 
-        for (ready, explicit_provider, expected_provider) in cases {
-            let dir = tempfile::tempdir().unwrap();
-            let mut settings = test_default_settings();
-            settings.run.model.name = Some("gpt-56-sol".to_string());
-            settings.run.model.provider = explicit_provider.map(str::to_string);
-            let store = memory_store();
-            let created = create(
-                store.as_ref(),
-                CreateRunInput {
-                    workflow: WorkflowInput::DotSource {
-                        source:   ALIAS_DOT.to_string(),
-                        base_dir: None,
+        for selector in ["gpt-56-sol", "openai/gpt-5.6-sol"] {
+            for (ready, explicit_provider, expected_provider) in &cases {
+                let dir = tempfile::tempdir().unwrap();
+                let mut settings = test_default_settings();
+                settings.run.model.name = Some(selector.to_string());
+                settings.run.model.provider = explicit_provider.map(str::to_string);
+                let store = memory_store();
+                let created = create(
+                    store.as_ref(),
+                    CreateRunInput {
+                        workflow: WorkflowInput::DotSource {
+                            source:   MODEL_DOT.replace("MODEL_SELECTOR", selector),
+                            base_dir: None,
+                        },
+                        settings,
+                        vars: HashMap::new(),
+                        cwd: dir.path().to_path_buf(),
+                        workflow_slug: None,
+                        workflow_path: None,
+                        workflow_bundle: None,
+                        submitted_manifest_bytes: None,
+                        run_id: None,
+                        title: None,
+                        automation: None,
+                        git: None,
+                        fork_source_ref: None,
+                        parent_id: None,
+                        provenance: test_support::test_run_provenance(),
+                        configured_providers: ready.clone(),
+                        web_url: None,
                     },
-                    settings,
-                    vars: HashMap::new(),
-                    cwd: dir.path().to_path_buf(),
-                    workflow_slug: None,
-                    workflow_path: None,
-                    workflow_bundle: None,
-                    submitted_manifest_bytes: None,
-                    run_id: None,
-                    title: None,
-                    automation: None,
-                    git: None,
-                    fork_source_ref: None,
-                    parent_id: None,
-                    provenance: test_support::test_run_provenance(),
-                    configured_providers: ready,
-                    web_url: None,
-                },
-                dir.path().join("storage"),
-                Arc::clone(&catalog),
-            )
-            .await
-            .unwrap();
-            let run_spec = created.persisted.run_spec();
+                    dir.path().join("storage"),
+                    Arc::clone(&catalog),
+                )
+                .await
+                .unwrap();
+                let run_spec = created.persisted.run_spec();
 
-            assert_eq!(
-                run_spec.settings.run.model.name.as_deref(),
-                Some("gpt-5.6-sol")
-            );
-            assert_eq!(
-                run_spec.settings.run.model.provider.as_deref(),
-                Some(expected_provider.as_str())
-            );
-            assert_eq!(
-                run_spec.graph.nodes["work"]
-                    .attrs
-                    .get("model")
-                    .and_then(AttrValue::as_str),
-                Some("gpt-5.6-sol")
-            );
-            assert_eq!(
-                run_spec.graph.nodes["work"]
-                    .attrs
-                    .get("provider")
-                    .and_then(AttrValue::as_str),
-                Some(expected_provider.as_str())
-            );
+                assert_eq!(
+                    run_spec.settings.run.model.name.as_deref(),
+                    Some("gpt-5.6-sol"),
+                    "{selector}"
+                );
+                assert_eq!(
+                    run_spec.settings.run.model.provider.as_deref(),
+                    Some(expected_provider.as_str()),
+                    "{selector}"
+                );
+                assert_eq!(
+                    run_spec.graph.nodes["work"]
+                        .attrs
+                        .get("model")
+                        .and_then(AttrValue::as_str),
+                    Some("gpt-5.6-sol"),
+                    "{selector}"
+                );
+                assert_eq!(
+                    run_spec.graph.nodes["work"]
+                        .attrs
+                        .get("provider")
+                        .and_then(AttrValue::as_str),
+                    Some(expected_provider.as_str()),
+                    "{selector}"
+                );
+
+                let run_store = store.open_run(&created.run_id).await.unwrap();
+                let run_store = run_store.into();
+                let reloaded = Persisted::load_from_store(&run_store, &created.run_dir)
+                    .await
+                    .unwrap();
+                assert_eq!(
+                    reloaded.run_spec().settings.run.model.provider.as_deref(),
+                    Some(expected_provider.as_str()),
+                    "{selector}"
+                );
+                assert_eq!(
+                    reloaded.run_spec().graph.nodes["work"]
+                        .attrs
+                        .get("provider")
+                        .and_then(AttrValue::as_str),
+                    Some(expected_provider.as_str()),
+                    "{selector}"
+                );
+                assert!(
+                    reloaded.source().contains(selector),
+                    "persisted source should preserve the user's selector '{selector}'"
+                );
+            }
         }
     }