diff --git a/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager+AccountRestoreExtension.swift b/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager+AccountRestoreExtension.swift
index 8b189534..557b2b38 100644
--- a/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager+AccountRestoreExtension.swift
+++ b/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager+AccountRestoreExtension.swift
@@ -983,6 +983,13 @@ extension SphinxOnionManager {
         restoredContactInfoTracker = []
     }
     
+    // NOTE: This timer is independent of the Rust CHUNK_TIMEOUT_SECS buffer timeout.
+    // Extending CHUNK_TIMEOUT_SECS in sphinx-ffi/src/chunk.rs alone does not extend how
+    // long this client waits — the timer below still fires at kMessageFetchTimeout (30s)
+    // and clears all fetch callbacks regardless of the server-side buffer tolerance.
+    // To fully benefit from a longer Rust chunk timeout, kMessageFetchTimeout must also
+    // be scaled accordingly — that is a separate client-side change and an explicit
+    // fast-follow candidate.
     func startMessageFetchTimeoutTimer() {
         DispatchQueue.main.async { [weak self] in
             guard let self = self else { return }
diff --git a/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager+HandleStateExtension.swift b/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager+HandleStateExtension.swift
index 00a2dcdb..77103cac 100644
--- a/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager+HandleStateExtension.swift
+++ b/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager+HandleStateExtension.swift
@@ -168,6 +168,25 @@ extension SphinxOnionManager {
         return getMessageTag(messages: rr.msgs, isSendingMessage: isSendingMessage)
     }
     
+    // MARK: - state_mp Persistence Requirement
+    //
+    // Any call that returns a RunReturn — including all fetch/chunk-bearing calls — MUST
+    // flow through handleRunReturn() (or at minimum updateStateMap()) before discarding
+    // the result. If it does not, the state_mp delta is silently dropped: any in-flight
+    // chunk buffer associated with that call will restart from scratch on the next
+    // fragment, with no error surfaced to the user.
+    //
+    // Fetch functions and their persistence status (as of 2026-07):
+    //   • fetch_msgs_batch         → exercised end-to-end via fetchMessageBlock
+    //                                (SphinxOnionManager+AccountRestoreExtension.swift)
+    //   • fetch_msgs_batch_per_contact → exercised end-to-end via fetchMessagePerContactBlock
+    //                                (SphinxOnionManager+AccountRestoreExtension.swift)
+    //   • fetchMsgs                → NO live call site in this app's business logic;
+    //                                persistence is only theoretically covered until a
+    //                                real caller is added and wired through handleRunReturn.
+    //   • fetchMsgsBatchOkkey      → NO live call site in this app's business logic;
+    //                                persistence is only theoretically covered until a
+    //                                real caller is added and wired through handleRunReturn.
     func updateStateMap(stateMap: Data?) {
         if let stateMap = stateMap {
             let _ = storeOnionState(inc: [UInt8](stateMap))
diff --git a/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager.swift b/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager.swift
index 7979e573..d3216ada 100644
--- a/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager.swift
+++ b/com.stakwork.sphinx.desktop/Crypter/SphinxOnionManager/SphinxOnionManager.swift
@@ -38,6 +38,15 @@ class SphinxOnionManager : NSObject, @unchecked Sendable {
     
     static let kMqttKeepAlive: UInt16 = 15
     static let kConnectionTimeoutInterval: TimeInterval = 15.0
+    // Client-side fetch watchdog — independent of Rust CHUNK_TIMEOUT_SECS
+    //
+    // This timeout drives startMessageFetchTimeoutTimer(), which calls clearFetchCallbacks()
+    // and abandons an in-flight fetch/restore after 30 seconds. It is entirely independent
+    // of the Rust-side CHUNK_TIMEOUT_SECS buffer timeout in sphinx-ffi/src/chunk.rs.
+    // Increasing CHUNK_TIMEOUT_SECS on the server/FFI side (e.g. to 300s) does NOT make
+    // this client wait longer — this watchdog will still fire at 30s and clear callbacks,
+    // preventing the app from benefiting from the extended Rust buffer tolerance.
+    // Scaling kMessageFetchTimeout to match is a separate, out-of-scope follow-up change.
     static let kMessageFetchTimeout: TimeInterval = 30.0
     
     var reconnectionTimer: Timer? = nil