diff --git a/src/openhuman/inference/embeddings/rpc.rs b/src/openhuman/inference/embeddings/rpc.rs
index e3513ee10a..3171df58db 100644
--- a/src/openhuman/inference/embeddings/rpc.rs
+++ b/src/openhuman/inference/embeddings/rpc.rs
@@ -1104,8 +1104,18 @@ mod tests {
         config.memory.embedding_provider = "cloud".to_string();
         // A managed session exists, so the ladder would resolve to cloud …
         std::fs::write(tmp.path().join("auth-profiles.json"), "{}").unwrap();
-        // … except the unified workload setting routes embeddings to Ollama.
+        // … except a local Ollama route wins. As of tinymemory v1.0.1 the
+        // effective-embedder ladder no longer treats the `embeddings_provider`
+        // string alone as authoritative for local routing — local Ollama is
+        // resolved from an explicit `memory_tree.embedding_endpoint` override or
+        // the unified `workload_local_model` setting. Drive the explicit
+        // endpoint rung here: it resolves deterministically without an installed
+        // embedding host, and still exercises the point of the test — that
+        // `provider` (the picker) stays `cloud` while `effective_provider`
+        // reports the local route that bills nothing (#5402).
         config.embeddings_provider = Some("ollama:all-minilm:latest".into());
+        config.memory_tree.embedding_endpoint = Some("http://localhost:11434".into());
+        config.memory_tree.embedding_model = Some("all-minilm".into());
 
         let out = get_settings(&config)
             .await
diff --git a/src/openhuman/inference/provider/openhuman_backend_model.rs b/src/openhuman/inference/provider/openhuman_backend_model.rs
index 18502f02e0..33b3d8d403 100644
--- a/src/openhuman/inference/provider/openhuman_backend_model.rs
+++ b/src/openhuman/inference/provider/openhuman_backend_model.rs
@@ -106,22 +106,44 @@ impl OpenHumanBackendModel {
     }
 
     fn resolve_bearer(&self) -> anyhow::Result<String> {
+        use crate::openhuman::security::credentials::session_support::{
+            classify_session_token, SessionTokenCheck,
+        };
+
         if crate::openhuman::cron::scheduler_gate::is_signed_out() {
             anyhow::bail!(
                 "SESSION_EXPIRED: backend session not active — sign in to resume LLM work"
             );
         }
         let auth = AuthService::new(&self.state_dir(), self.options.secrets_encrypt);
-        if let Some(token) = auth
-            .get_provider_bearer_token(
-                APP_SESSION_PROVIDER,
-                self.options.auth_profile_override.as_deref(),
-            )?
-            .filter(|token| !token.trim().is_empty())
-        {
-            return Ok(token);
+        let profile = auth.get_profile(
+            APP_SESSION_PROVIDER,
+            self.options.auth_profile_override.as_deref(),
+        )?;
+
+        // #5503: precheck the recorded JWT `exp` BEFORE building a request, the
+        // same way `require_live_session_token` guards the backend REST callers.
+        // Managed inference used to fire a doomed request on an expired-but-
+        // stored token and let the 401 come back — but an expired session can
+        // also surface upstream as a misleading "model unavailable", which is a
+        // core symptom of #5503 (all tiers "die" over a long session). Failing
+        // fast as `session_expired` routes the user to re-auth instead. Offline
+        // / local sessions (`is_local_session_token`) and `exp`-less tokens
+        // carry no recorded expiry, so `classify_session_token` returns `Live`
+        // for them — their behaviour is unchanged and the post-call 401 net
+        // still covers a server-side revocation.
+        match classify_session_token(profile.as_ref(), chrono::Utc::now()) {
+            SessionTokenCheck::Live(token) => Ok(token),
+            SessionTokenCheck::Expired => {
+                maybe_publish_local_session_expiry();
+                anyhow::bail!(
+                    "SESSION_EXPIRED: backend session token expired locally — re-authentication required"
+                )
+            }
+            SessionTokenCheck::Absent => {
+                anyhow::bail!("No backend session: store a JWT via auth (app-session)")
+            }
         }
-        anyhow::bail!("No backend session: store a JWT via auth (app-session)")
     }
 
     fn base_url(&self) -> String {
@@ -381,6 +403,27 @@ fn with_thread_id(mut request: ModelRequest) -> ModelRequest {
     request
 }
 
+/// Publish a `SessionExpired` event when the local `exp` precheck in
+/// [`resolve_bearer`](OpenHumanBackendModel::resolve_bearer) rejects an expired
+/// managed session token before a request is ever sent — mirroring
+/// [`require_live_session_token`](crate::openhuman::security::credentials::session_support::require_live_session_token)'s
+/// pre-flight publish so the credentials subscriber clears state and the UI
+/// re-auths exactly as it would on a real backend 401. Deduped via the
+/// scheduler gate so N parallel managed turns in one tick don't emit N events.
+fn maybe_publish_local_session_expiry() {
+    if crate::openhuman::cron::scheduler_gate::is_signed_out() {
+        return;
+    }
+    log::warn!(
+        "[providers][openhuman-backend] managed session token expired locally — \
+         publishing SessionExpired before any inference request"
+    );
+    crate::core::bus::BUS.publish(crate::core::events::DomainEvent::SessionExpired {
+        source: "openhuman_backend_model.resolve_bearer".to_string(),
+        reason: "backend session token expired locally — re-authentication required".to_string(),
+    });
+}
+
 /// Publish a `SessionExpired` event when the backend rejects a crate-native
 /// model call with `401`/`403` Unauthorized — mirroring the check in
 /// [`CrateBackedProvider::invoke`](super::CrateBackedProvider) which the
@@ -402,6 +445,36 @@ fn maybe_publish_session_expired(err: &TinyAgentsError, operation: &str) {
     }
 }
 
+/// Log the raw upstream failure at the managed inference dispatch boundary
+/// (#5503, part d). The managed unavailability path used to surface the true
+/// backend cause only after the web-chat error classifier had already collapsed
+/// it to a user-facing bucket, so an operator investigating "all tiers died
+/// over hours" had no record of what the backend actually returned. This is the
+/// one place every managed `invoke`/`stream` failure passes through, so it's
+/// where the diagnostic belongs. Structured fields (`status`/`code`/`provider`/
+/// `retryable`) are low-cardinality; the message is secret-scrubbed and capped
+/// by [`sanitize_api_error`] before it's logged — no tokens, no full PII.
+fn log_managed_dispatch_error(err: &TinyAgentsError, operation: &str) {
+    match err {
+        TinyAgentsError::Provider(pe) => {
+            log::warn!(
+                "[providers][openhuman-backend] managed {operation} failed: status={:?} code={:?} provider={} retryable={} detail={}",
+                pe.status,
+                pe.code,
+                pe.provider,
+                pe.retryable,
+                crate::openhuman::inference::provider::ops::sanitize_api_error(&pe.message),
+            );
+        }
+        other => {
+            log::warn!(
+                "[providers][openhuman-backend] managed {operation} failed (non-provider error): {}",
+                crate::openhuman::inference::provider::ops::sanitize_api_error(&other.to_string()),
+            );
+        }
+    }
+}
+
 #[async_trait]
 impl ChatModel<()> for OpenHumanBackendModel {
     fn profile(&self) -> Option<&ModelProfile> {
@@ -413,6 +486,7 @@ impl ChatModel<()> for OpenHumanBackendModel {
         let response = match model.invoke(state, with_thread_id(request)).await {
             Ok(response) => response,
             Err(e) => {
+                log_managed_dispatch_error(&e, "invoke");
                 maybe_publish_session_expired(&e, "invoke");
                 return Err(e);
             }
@@ -432,6 +506,7 @@ impl ChatModel<()> for OpenHumanBackendModel {
         match model.stream(state, with_thread_id(request)).await {
             Ok(stream) => Ok(stream),
             Err(e) => {
+                log_managed_dispatch_error(&e, "stream");
                 maybe_publish_session_expired(&e, "stream");
                 Err(e)
             }
@@ -690,6 +765,27 @@ mod tests {
             .expect("seed app-session token");
     }
 
+    /// Seed an app-session profile whose recorded `exp` metadata is `expires_at`
+    /// (RFC3339) so the `resolve_bearer` local-expiry precheck (#5503, part e)
+    /// can be exercised without a live backend.
+    fn seed_app_session_with_expiry(dir: &std::path::Path, expires_at: &str) {
+        use crate::openhuman::security::credentials::{
+            session_support::SESSION_EXPIRES_AT_META, AuthService, APP_SESSION_PROVIDER,
+            DEFAULT_AUTH_PROFILE_NAME,
+        };
+        let mut metadata = std::collections::HashMap::new();
+        metadata.insert(SESSION_EXPIRES_AT_META.to_string(), expires_at.to_string());
+        AuthService::new(dir, false)
+            .store_provider_token(
+                APP_SESSION_PROVIDER,
+                DEFAULT_AUTH_PROFILE_NAME,
+                "test.session.jwt",
+                metadata,
+                true,
+            )
+            .expect("seed app-session token with expiry");
+    }
+
     fn backend_pointed_at(addr: &str, dir: &std::path::Path) -> OpenHumanBackendModel {
         OpenHumanBackendModel::new(
             Some(&format!("http://{addr}")),
@@ -819,4 +915,64 @@ mod tests {
             "probe must return around the 5s timeout, not wait for the slow handler"
         );
     }
+
+    // ── resolve_bearer local-expiry precheck (#5503, part e) ───────────────
+
+    #[test]
+    fn resolve_bearer_fast_fails_session_expired_on_expired_token() {
+        // An app-session JWT whose recorded `exp` is in the past must fail the
+        // precheck as a `SESSION_EXPIRED` sentinel BEFORE any request is built —
+        // so the web-chat classifier routes it to `session_expired` (actionable
+        // re-auth) instead of a doomed request that can surface as a misleading
+        // "model unavailable" (#5503). No backend is stood up: a correct
+        // precheck never reaches the network.
+        let tmp = tempfile::TempDir::new().unwrap();
+        let past = (chrono::Utc::now() - chrono::Duration::hours(1)).to_rfc3339();
+        seed_app_session_with_expiry(tmp.path(), &past);
+        let backend = backend_pointed_at("127.0.0.1:9", tmp.path());
+
+        let err = backend
+            .resolve_bearer()
+            .expect_err("an expired managed JWT must fast-fail the precheck");
+        let msg = err.to_string();
+        assert!(
+            msg.contains("SESSION_EXPIRED"),
+            "must carry the SESSION_EXPIRED sentinel the classifier keys on: {msg}"
+        );
+        assert!(
+            crate::core::observability::is_session_expired_message(&msg),
+            "must classify as session-expiry, not model-unavailable: {msg}"
+        );
+    }
+
+    #[test]
+    fn resolve_bearer_returns_token_when_expiry_in_future() {
+        // A recorded `exp` comfortably in the future resolves normally — the
+        // precheck only rejects the past-expiry case.
+        let tmp = tempfile::TempDir::new().unwrap();
+        let future = (chrono::Utc::now() + chrono::Duration::hours(1)).to_rfc3339();
+        seed_app_session_with_expiry(tmp.path(), &future);
+        let backend = backend_pointed_at("127.0.0.1:9", tmp.path());
+
+        let token = backend
+            .resolve_bearer()
+            .expect("a live (future-exp) managed JWT must resolve");
+        assert_eq!(token, "test.session.jwt");
+    }
+
+    #[test]
+    fn resolve_bearer_returns_token_for_exp_less_offline_session() {
+        // Offline / local sessions record no `exp`, so the precheck falls
+        // through to presence-only and their behaviour is unchanged (the
+        // post-call 401 net still covers a server-side revocation). Guards the
+        // #5503 precheck against breaking the offline path.
+        let tmp = tempfile::TempDir::new().unwrap();
+        seed_app_session(tmp.path());
+        let backend = backend_pointed_at("127.0.0.1:9", tmp.path());
+
+        let token = backend
+            .resolve_bearer()
+            .expect("an exp-less offline session must resolve (presence-only)");
+        assert_eq!(token, "test.session.jwt");
+    }
 }
diff --git a/src/openhuman/web_chat/web_errors.rs b/src/openhuman/web_chat/web_errors.rs
index 5ab28db4a6..36daf15ebf 100644
--- a/src/openhuman/web_chat/web_errors.rs
+++ b/src/openhuman/web_chat/web_errors.rs
@@ -858,17 +858,46 @@ pub(crate) fn classify_inference_error(err: &str) -> ClassifiedError {
             || lower.contains("does not exist")
             || lower.contains("does not have access"))
     {
-        ClassifiedError {
-            error_type: "model_unavailable",
-            message: with_provider_detail(
-                "The selected model isn't available on your provider. Check your model settings.",
-                err,
-            ),
-            source: "config",
-            retryable: false,
-            retry_after_ms: None,
-            provider,
-            fallback_available: None,
+        // #5503: this arm previously flattened two distinct failures into one
+        // non-retryable "check your model settings" misconfiguration verdict.
+        // A TRANSIENT upstream outage ("the model is temporarily unavailable",
+        // "currently overloaded") is NOT a user misconfiguration — labelling it
+        // `config`/non-retryable tells the user to go fix settings that are
+        // fine, and hides the Retry button on a failure a retry would clear. So
+        // split on transience: a body carrying a temporary-outage marker routes
+        // to the retryable "temporarily unavailable" provider copy (the same
+        // class as the `500`/`503` arm above), while a genuine model rejection
+        // ("does not exist", "does not have access", "model unavailable on this
+        // endpoint" — a stale pin / wrong endpoint) keeps the non-retryable
+        // config copy. Genuine config-rejection bodies (`does not exist`,
+        // `model_not_found`, `/openai/v1/models`, …) are already claimed by the
+        // provider-config-rejection arm above and never reach here.
+        if is_transient_unavailability_text(&lower) {
+            ClassifiedError {
+                error_type: "provider_error",
+                message: with_provider_detail(
+                    "The AI provider is temporarily unavailable. Please try again later.",
+                    err,
+                ),
+                source: "provider",
+                retryable: true,
+                retry_after_ms: None,
+                provider,
+                fallback_available,
+            }
+        } else {
+            ClassifiedError {
+                error_type: "model_unavailable",
+                message: with_provider_detail(
+                    "The selected model isn't available on your provider. Check your model settings.",
+                    err,
+                ),
+                source: "config",
+                retryable: false,
+                retry_after_ms: None,
+                provider,
+                fallback_available: None,
+            }
         }
     } else if lower.contains("does not support vision") || lower.contains("capability=vision") {
         // A multimodal turn sent image markers to a text-only model
@@ -953,6 +982,22 @@ pub(crate) fn classify_inference_error(err: &str) -> ClassifiedError {
             provider,
             fallback_available,
         }
+    } else if is_transient_unavailability_text(&lower) {
+        // A transient upstream-outage marker that no more specific arm above
+        // claimed (e.g. a bare 5xx "overloaded" such as Anthropic's 529, or
+        // "please retry later") is a temporary provider outage — surface the
+        // retryable "temporarily unavailable" provider copy rather than the flat
+        // inference bucket, so the user gets an accurate, retryable error (#5503).
+        ClassifiedError {
+            error_type: "provider_error",
+            message: "The AI provider is temporarily unavailable. Please try again later."
+                .to_string(),
+            source: "provider",
+            retryable: true,
+            retry_after_ms: None,
+            provider,
+            fallback_available,
+        }
     } else {
         ClassifiedError {
             error_type: "inference",
@@ -1079,6 +1124,35 @@ pub(crate) fn is_provider_request_rejected_text(lower: &str) -> bool {
         .any(|marker| lower.contains(marker))
 }
 
+/// Whether a model-availability error body describes a **transient** upstream
+/// outage rather than a user misconfiguration (#5503).
+///
+/// The `model_unavailable` arm matches on the bare word `unavailable`, which a
+/// provider emits for BOTH "you picked a model I don't host" (config, terminal)
+/// and "this model is temporarily down / overloaded right now" (transient,
+/// retryable). Only the second class carries one of these temporary-outage
+/// markers, so it's the safe discriminator: a terminal endpoint rejection like
+/// `"model unavailable on this endpoint"` (a 404 for a model that endpoint
+/// doesn't host) carries none of them and stays on the config verdict.
+///
+/// Deliberately does NOT key on the bare word `unavailable` — that's the very
+/// ambiguity being disambiguated. Caller passes the already-lowercased string.
+pub(crate) fn is_transient_unavailability_text(lower: &str) -> bool {
+    const TRANSIENT_MARKERS: &[&str] = &[
+        "temporarily",
+        "temporary",
+        "currently unavailable",
+        "currently overloaded",
+        "overloaded",
+        "try again later",
+        "try again in a",
+        "please retry",
+    ];
+    TRANSIENT_MARKERS
+        .iter()
+        .any(|marker| lower.contains(marker))
+}
+
 /// String-flat mirror of
 /// [`crate::openhuman::inference::provider::error_classify::is_non_retryable_rate_limit`].
 ///
diff --git a/src/openhuman/web_chat/web_tests.rs b/src/openhuman/web_chat/web_tests.rs
index 582361fb4b..0e43b0e9f1 100644
--- a/src/openhuman/web_chat/web_tests.rs
+++ b/src/openhuman/web_chat/web_tests.rs
@@ -342,6 +342,139 @@ fn classify_inference_error_chat_factory_empty_model_is_actionable_config() {
     );
 }
 
+// ── #5503: transient model-unavailable vs misconfiguration ─────
+
+#[test]
+fn classify_inference_error_transient_model_unavailable_is_retryable_not_config() {
+    // #5503: a BYO/direct-provider body that says the model is *temporarily*
+    // down (a transient upstream outage — the real symptom behind "all tiers
+    // die over a long session") must NOT be flattened into the non-retryable
+    // "check your model settings" misconfiguration copy. It routes to the
+    // retryable "temporarily unavailable" provider class instead, so the FE
+    // keeps the Retry button and doesn't send the user to fix settings that
+    // are fine. Each of these carries a temporary-outage marker.
+    for raw in [
+        r#"custom_openai API error (503 Service Unavailable): {"error":{"message":"The model is temporarily unavailable, please try again later."}}"#,
+        r#"cloud API error (529): {"error":{"message":"model is currently overloaded"}}"#,
+        r#"openrouter API error (503): {"error":{"message":"This model is temporarily unavailable. Please retry."}}"#,
+    ] {
+        let ClassifiedError {
+            error_type,
+            message,
+            retryable,
+            source,
+            ..
+        } = classify_inference_error(raw);
+        assert_eq!(
+            error_type, "provider_error",
+            "transient model outage must classify as provider_error, not model_unavailable: {raw}"
+        );
+        assert!(
+            retryable,
+            "transient model outage must stay retryable (keep Retry): {raw}"
+        );
+        assert_eq!(
+            source, "provider",
+            "transient outage is a provider fault: {raw}"
+        );
+        assert!(
+            message.contains("temporarily unavailable"),
+            "must use the temporarily-unavailable copy: {message}"
+        );
+        assert!(
+            !message.to_lowercase().contains("check your model settings"),
+            "must NOT tell the user their configuration is wrong: {message}"
+        );
+    }
+}
+
+#[test]
+fn classify_inference_error_genuine_model_rejection_stays_nonretryable_config() {
+    // Guard the other direction: a genuine model rejection with NO
+    // temporary-outage marker (wrong endpoint, no access) keeps the
+    // non-retryable `model_unavailable` + "check your model settings" config
+    // verdict. This is the half of the #5503 split that must not regress the
+    // pre-existing behaviour.
+    for raw in [
+        // Endpoint doesn't host this model (a terminal 404, not a transient dip).
+        r#"custom_openai API error (404 Not Found): {"error":{"message":"model unavailable on this endpoint"}}"#,
+        // No access to the requested model — bare "not found", no outage marker.
+        r#"custom_openai API error (404 Not Found): {"error":{"message":"the requested model was not found for this account"}}"#,
+    ] {
+        let ClassifiedError {
+            error_type,
+            message,
+            retryable,
+            source,
+            ..
+        } = classify_inference_error(raw);
+        assert_eq!(
+            error_type, "model_unavailable",
+            "genuine model rejection must stay model_unavailable: {raw}"
+        );
+        assert!(
+            !retryable,
+            "genuine model rejection is non-retryable (hide Retry): {raw}"
+        );
+        assert_eq!(
+            source, "config",
+            "genuine model rejection is user config: {raw}"
+        );
+        assert!(
+            message.contains("Check your model settings"),
+            "must keep the actionable config copy: {message}"
+        );
+    }
+}
+
+#[test]
+fn classify_inference_error_transient_model_unavailable_without_5xx_status_uses_split_arm() {
+    // #5503 coverage guard for the split's *own* true branch. The two fixtures
+    // in `..._is_retryable_not_config` above each carry a `503`/`529` status, so
+    // they are already claimed by the generic 5xx arm and never reach the
+    // model-unavailable split. A transient outage reported with NO 5xx status —
+    // a bare provider body that only says the model is temporarily unavailable /
+    // currently unavailable — can be rescued from the non-retryable "check your
+    // model settings" verdict *only* by the split arm itself. So this exercises
+    // the branch the other fixtures miss: each body carries the "model" +
+    // "unavailable" trigger (so it enters the model arm, not the 5xx arm) plus a
+    // temporary-outage marker (so it takes the retryable TRUE branch). On the
+    // pre-#5503 flattened code these classified as non-retryable
+    // `model_unavailable`; the split makes them retryable `provider_error`.
+    for raw in [
+        r#"custom_openai API error: {"error":{"message":"The model is temporarily unavailable, please try again later."}}"#,
+        r#"openrouter API error: {"error":{"message":"This model is currently unavailable; please retry shortly."}}"#,
+    ] {
+        let ClassifiedError {
+            error_type,
+            message,
+            retryable,
+            source,
+            ..
+        } = classify_inference_error(raw);
+        assert_eq!(
+            error_type, "provider_error",
+            "no-status transient outage must reach the split arm as provider_error, not model_unavailable: {raw}"
+        );
+        assert!(
+            retryable,
+            "no-status transient outage must stay retryable (keep Retry): {raw}"
+        );
+        assert_eq!(
+            source, "provider",
+            "transient outage is a provider fault: {raw}"
+        );
+        assert!(
+            message.contains("temporarily unavailable"),
+            "must use the temporarily-unavailable copy: {message}"
+        );
+        assert!(
+            !message.to_lowercase().contains("check your model settings"),
+            "must NOT tell the user their configuration is wrong: {message}"
+        );
+    }
+}
+
 // ── #2364: rate-limit classification + retry-after surfacing ────
 
 #[test]