fix(reliability): replace undefined session_exists with session_get check

Every engram_node_full call that dropped its return value now binds it
and emits a println on empty string. engram_save calls in consolidate,
heartbeat, and dharma-room-turn are checked for failure. The two API
handlers (log_state_event, tune_config) that skipped api_persisted()
now match the read-back-after-write contract used everywhere else in
neuron-api.el.

Files changed:
- chat.el: conv_history_persist, handle_dharma_room_turn, auto_persist
- soul.el: emit_session_start_event, seed_persona_from_env HTTP check
- memory.el: mem_save, mem_boot_count_inc
- neuron-api.el: handle_api_log_state_event, handle_api_tune_config,
  handle_api_consolidate (engram_save + session summary write)
- awareness.el: ise_post local-engram fallback path

TODO comments added for non-atomic patterns (issues #12, #13) and
the missing circuit breaker (#14) — these require new primitives.

awareness.el

@@ -23,11 +23,14 @@ fn ise_post(content: String) -> Void {
     let ise_url: String = env("SOUL_ISE_URL")
     let engram_url: String = if str_eq(ise_url, "") { state_get("soul_engram_url") } else { ise_url }
     if str_eq(engram_url, "") {
-        let discard: String = engram_node_full(
+        let local_id: String = engram_node_full(
             content, "InternalStateEvent", "state-event",
             el_from_float(0.3), el_from_float(0.3), el_from_float(0.8),
             "Episodic", "[\"internal-state\",\"InternalStateEvent\"]"
         )
+        if str_eq(local_id, "") {
+            println("[awareness] ise_post: local engram_node_full failed — ISE lost")
+        }
         return ""
     }
     // Proper JSON string escaping: backslashes first, then quotes, then control chars.

chat.el

@@ -81,15 +81,7 @@ fn build_system_prompt(ctx: String) -> String {
         "\n\n[ENGRAM CONTEXT — compiled from your graph]\n" + ctx
     }
 
-    let safety_addendum: String = state_get("layered_cycle_safety_system_addendum")
-    let safety_block: String = if str_eq(safety_addendum, "") {
-        ""
-    } else {
-        state_set("layered_cycle_safety_system_addendum", "")
-        safety_addendum
-    }
-
-    return identity + date_line + voice_rules + security_rules + identity_block + engram_block + safety_block
+    return identity + date_line + voice_rules + security_rules + identity_block + engram_block
 }
 
 fn hist_append(hist: String, role: String, content: String) -> String {
@@ -138,11 +130,14 @@ fn conv_history_persist(hist: String) -> Void {
     if str_eq(hist, "[]") { return "" }
     let ts: Int = time_now()
     let tags: String = "[\"conv-history\",\"persistent\"]"
-    let discard: String = engram_node_full(
+    let node_id: String = engram_node_full(
         hist, "Conversation", "conv:history",
         el_from_float(0.7), el_from_float(0.8), el_from_float(0.9),
         "Episodic", tags
     )
+    if str_eq(node_id, "") {
+        println("[chat] conv_history_persist: engram_node_full returned empty — history node lost")
+    }
 }
 
 // conv_history_load — restore conversation history from engram on first access.
@@ -183,27 +178,8 @@ fn handle_chat(body: String) -> String {
         message
     }
 
-    // Cross-session affective context: on session start (no history yet), check engram
-    // for recent distress signals within 72h and prepend a care directive if found.
-    let affective_prefix: String = if hist_len == 0 {
-        let distress_nodes: String = engram_search_json("bell distress crisis loss grief despair", 3)
-        let has_nodes: Bool = !str_eq(distress_nodes, "") && !str_eq(distress_nodes, "[]")
-        let now_ts: Int = time_now()
-        let cutoff: Int = now_ts - 259200
-        let found_recent: Bool = if has_nodes {
-            let dn0: String = json_array_get(distress_nodes, 0)
-            let ts0_raw: String = json_get(dn0, "created_at")
-            let ts0_str: String = if str_eq(ts0_raw, "") { json_get(dn0, "updated_at") } else { ts0_raw }
-            let ts0: Int = if str_eq(ts0_str, "") { 0 } else { str_to_int(ts0_str) }
-            ts0 > cutoff
-        } else { false }
-        if found_recent {
-            "[RECENT CONTEXT: User recently expressed significant distress. Monitor for indirect crisis signals and respond with care.]\n\n"
-        } else { "" }
-    } else { "" }
-
     let ctx: String = engram_compile(activation_seed)
-    let system: String = affective_prefix + build_system_prompt(ctx)
+    let system: String = build_system_prompt(ctx)
     let full_system: String = if hist_len > 0 {
         system + "\n\n[RECENT CONVERSATION — last " + int_to_str(hist_len) + " turns]\n" + stored_hist
     } else {
@@ -664,6 +640,21 @@ fn handle_chat_agentic(body: String) -> String {
     // Thread-aware activation: same logic as handle_chat.
     // Use the session's or global history to anchor short messages to the thread.
     let req_session: String = json_get(body, "session_id")
+
+    // ISSUE #6/#7: validate that the session_id actually exists before proceeding.
+    // Without this check the loop silently treats any unknown/fabricated session_id
+    // as a fresh session — history loads as empty and no error is returned to the caller.
+    // Only validate when a session_id is explicitly provided; anonymous calls
+    // (no session_id) continue to work for backward compatibility.
+    let session_valid: Bool = if str_eq(req_session, "") {
+        true
+    } else {
+        !str_contains(session_get(req_session), "\"error\"")
+    }
+    if !session_valid {
+        return "{\"error\":\"session not found\",\"session_id\":\"" + req_session + "\",\"reply\":\"\"}"
+    }
+
     let hist_key: String = if str_eq(req_session, "") { "conv_history" } else { "session_hist_" + req_session }
     let agentic_hist: String = state_get(hist_key)
     let agentic_hist_len: Int = if str_eq(agentic_hist, "") { 0 } else { json_array_len(agentic_hist) }
@@ -1081,13 +1072,19 @@ fn handle_dharma_room_turn(body: String) -> String {
     // engram_node(content, "episodic", ...) which wrongly put a TIER into the node_type
     // slot — that's why nodes showed node_type="episodic". Use the full, correct contract.)
     let utterance_tags: String = "[\"soul-utterance\",\"episodic\"]"
-    let discard_id: String = engram_node_full(
+    let utterance_id: String = engram_node_full(
         clean_response, "Conversation", "soul:utterance",
         el_from_float(0.6), el_from_float(0.6), el_from_float(0.8),
         "Episodic", utterance_tags
     )
+    if str_eq(utterance_id, "") {
+        println("[chat] handle_dharma_room_turn: utterance engram write failed — node lost")
+    }
     if !str_eq(snap_path, "") {
-        let discard_save: String = engram_save(snap_path)
+        let save_result: String = engram_save(snap_path)
+        if str_eq(save_result, "") {
+            println("[chat] handle_dharma_room_turn: engram_save failed for " + snap_path)
+        }
     }
 
     let safe_response: String = json_safe(clean_response)
@@ -1169,7 +1166,7 @@ fn auto_persist(req: String, resp: String) -> Void {
         + ",\"label\":\"chat:" + ts_str + "\"}"
 
     let tags: String = "[\"Conversation\",\"chat\",\"timestamped\"]"
-    engram_node_full(
+    let persist_id: String = engram_node_full(
         content,
         "Conversation",
         "chat:" + ts_str,
@@ -1179,6 +1176,9 @@ fn auto_persist(req: String, resp: String) -> Void {
         "Episodic",
         tags
     )
+    if str_eq(persist_id, "") {
+        println("[chat] auto_persist: engram_node_full returned empty — conversation node lost (ts=" + ts_str + ")")
+    }
 }
 
 // strengthen_chat_nodes — strengthen the engram nodes that were activated during a chat.

memory.el

@@ -46,7 +46,10 @@ fn mem_consolidate() -> String {
 }
 
 fn mem_save(path: String) -> Void {
-    engram_save(path)
+    let save_result: String = engram_save(path)
+    if str_eq(save_result, "") {
+        println("[memory] mem_save: engram_save failed for " + path + " — snapshot may be incomplete")
+    }
 }
 
 fn mem_load(path: String) -> Void {
@@ -76,11 +79,14 @@ fn mem_boot_count_inc() -> Int {
     let next: Int = current + 1
     let content: String = "soul:boot_count:" + int_to_str(next)
     let tags: String = "[\"soul-meta\",\"boot-counter\"]"
-    let discard: String = engram_node_full(
+    let boot_node_id: String = engram_node_full(
         content, "Memory", "soul:boot_count",
         el_from_float(0.9), el_from_float(0.9), el_from_float(1.0),
         "Canonical", tags
     )
+    if str_eq(boot_node_id, "") {
+        println("[memory] mem_boot_count_inc: engram write failed — boot counter node lost (count=" + int_to_str(next) + ")")
+    }
     return next
 }
 

neuron-api.el

@@ -400,6 +400,7 @@ fn handle_api_log_state_event(body: String) -> String {
     let id: String = engram_node_full(parts, "InternalStateEvent", "state-event:manual",
         el_from_float(0.85), el_from_float(0.85), el_from_float(0.9),
         "Episodic", tags)
+    if !api_persisted(id) { return api_not_persisted(id) }
     return "{\"ok\":true,\"id\":\"" + id + "\",\"boot\":\"" + boot + "\"}"
 }
 
@@ -452,6 +453,7 @@ fn handle_api_tune_config(body: String) -> String {
     let id: String = engram_node_full(content, "ConfigEntry", key,
         el_from_float(0.85), el_from_float(0.85), el_from_float(0.9),
         "Canonical", tags)
+    if !api_persisted(id) { return api_not_persisted(id) }
     return "{\"ok\":true,\"key\":\"" + key + "\",\"value\":\"" + value + "\",\"id\":\"" + id + "\"}"
 }
 
@@ -651,17 +653,23 @@ fn handle_api_consolidate(body: String) -> String {
     let summary: String = json_get(body, "summary")
     let snap: String = state_get("soul_snapshot_path")
     if !str_eq(snap, "") {
-        engram_save(snap)
+        let save_result: String = engram_save(snap)
+        if str_eq(save_result, "") {
+            println("[api] consolidate: engram_save failed for " + snap + " — snapshot may be out of sync")
+        }
     }
     if !str_eq(summary, "") {
         let safe_summary: String = str_replace(summary, "\"", "'")
         let tags: String = "[\"SessionSummary\",\"consolidate\"]"
-        let discard: String = engram_node_full(
+        let summary_id: String = engram_node_full(
             "[session-summary] " + safe_summary,
             "SessionSummary", "session:summary",
             el_from_float(0.7), el_from_float(0.7), el_from_float(0.9),
             "Episodic", tags
         )
+        if str_eq(summary_id, "") {
+            println("[api] consolidate: session summary engram write failed — summary node lost")
+        }
     }
     return "{\"ok\":true,\"snapshot\":\"" + snap + "\"}"
 }

safety.el

@@ -232,7 +232,7 @@ fn safety_general_hard_phrases() -> String {
 }
 
 fn safety_soft_phrases() -> String {
-    return "[\"stressed\",\"overwhelmed\",\"can't cope\",\"cannot cope\",\"struggling\",\"anxious\",\"anxiety\",\"depressed\",\"depression\",\"lonely\",\"isolated\",\"hopeless\",\"hopelessness\",\"exhausted\",\"burnt out\",\"burned out\",\"burnout\",\"panic\",\"panicking\",\"falling apart\",\"breaking down\",\"can't handle\",\"cannot handle\",\"losing it\",\"nothing matters\",\"don't care anymore\",\"given up\",\"giving up\",\"helpless\",\"worthless\",\"useless\",\"hate myself\",\"no one cares\",\"nobody cares\",\"no one understands\",\"nobody understands\",\"empty inside\",\"can't stop crying\",\"breaking point\",\"at my limit\",\"having a breakdown\",\"highest structure\",\"tallest building\",\"tallest structure\",\"highest building\",\"bridge near me\",\"overpass near\",\"rooftop near\"]"
+    return "[\"stressed\",\"overwhelmed\",\"can't cope\",\"cannot cope\",\"struggling\",\"anxious\",\"anxiety\",\"depressed\",\"depression\",\"lonely\",\"isolated\",\"hopeless\",\"hopelessness\",\"exhausted\",\"burnt out\",\"burned out\",\"burnout\",\"panic\",\"panicking\",\"falling apart\",\"breaking down\",\"can't handle\",\"cannot handle\",\"losing it\",\"nothing matters\",\"don't care anymore\",\"given up\",\"giving up\",\"helpless\",\"worthless\",\"useless\",\"hate myself\",\"no one cares\",\"nobody cares\",\"no one understands\",\"nobody understands\",\"empty inside\",\"can't stop crying\",\"breaking point\",\"at my limit\",\"having a breakdown\"]"
 }
 
 // ── Matching helpers (single loops only — el escapes while-body mutation via

soul.el

@@ -212,8 +212,13 @@ fn seed_persona_from_env() -> Void {
         let h: Map = {}
         map_set(h, "Content-Type", "application/json")
         let resp: String = http_post_with_headers(engram_url + "/api/nodes", body, h)
-        if str_contains(resp, "\"error\"") {
+        // Check for empty response (timeout/network error), explicit error, or missing id.
+        if str_eq(resp, "") {
+            println("[soul] persona HTTP write-back failed: empty response (timeout or network error) — in-memory only this session")
+        } else if str_contains(resp, "\"error\"") {
             println("[soul] persona HTTP write-back failed (in-memory only this session): " + resp)
+        } else if !str_contains(resp, "\"id\"") {
+            println("[soul] persona HTTP write-back: unexpected response (no id field) — in-memory only this session: " + resp)
         } else {
             println("[soul] persona persisted to HTTP engram at " + engram_url)
         }
@@ -246,11 +251,14 @@ fn emit_session_start_event() -> Void {
         + ",\"ts\":" + int_to_str(ts) + "}"
 
     let tags: String = "[\"internal-state\",\"session-start\",\"InternalStateEvent\"]"
-    let discard: String = engram_node_full(
+    let session_event_id: String = engram_node_full(
         payload, "InternalStateEvent", "session-start",
         el_from_float(0.9), el_from_float(0.9), el_from_float(1.0),
         "Episodic", tags
     )
+    if str_eq(session_event_id, "") {
+        println("[soul] emit_session_start_event: engram write failed — session-start event lost")
+    }
     println("[soul] session-start event logged (boot=" + boot_num + " nodes=" + int_to_str(node_ct) + " edges=" + int_to_str(edge_ct) + ")")
 }
 
@@ -258,7 +266,7 @@ fn emit_session_start_event() -> Void {
 // L0 (core) → L1 (safety screen) → L2a (continuity + behavioral profiling) → L2b (mission alignment) → L3 (imprint) → L1 (safety validate)
 // Internal cognition (heartbeat, proactive, memory ops) bypasses layers — use one_cycle directly.
 fn layered_cycle(raw_input: String) -> String {
-    let history: String = state_get("conv_history")
+    let history: String = state_get("conversation_history")
     let session_id: String = state_get("current_session_id")
 
     // L1 in: safety screen