fix(recall): address all remaining code review issues

Issue 1 (CRITICAL): Fix auto_persist brace structure. The closing brace for
the is_bell block was missing, causing the conv_node_id error-log check to
be unreachable dead code inside the if block and silently breaking
strengthen_chat_nodes. Add the missing } to close the is_bell block before
the conv_node_id guard.

Issue 2 (CRITICAL): Restore session_exists() call in handle_chat_agentic.
The behavioral regression replacing session_exists() with
!str_contains(session_get(...), '"error"') was reverted. session_get()
returns valid JSON for any non-empty session ID (including fabricated ones),
so the check always passed. session_exists() does a proper state-index and
engram search.

Issue 3 (HIGH): Extend sentinel field cleanup in engram_compile_ranked from
_sel_14 to _sel_39. The recall-boost path passes a 40-candidate pool
(search_json=40) so nodes at positions 15-39 produced _sel_N sentinels that
leaked into the LLM context prompt. Cleanup chain now covers all 40 indices.

Issue 4 (HIGH): Fix engram_is_continuation false positives. Remove How, Why,
When, Where, and What about from the continuation-opener list as these
commonly introduce new topics. Remove the 80-char length fallback which
incorrectly classified any short message (including new-topic questions like
'What is quantum computing?') as a continuation.

Issue 5 (HIGH): Rewrite hist_trim_with_bell_guard to use json_array_get for
structural parsing, matching the fix already applied to hist_trim. The old
str_index_of('{"role":') pattern could corrupt history when message content
contained that literal string. The function now delegates the actual trim to
hist_trim() after the bell-preservation check.

Issue 6 (NORMAL): Fix entity_count scoping in engram_extract_entities. Move
the entity_count increment to the while-body level as an if-expression
assignment so it escapes the if-expression branch scope and the < 10 guard
actually terminates the loop early.

Issue 7 (NORMAL): Fix mcp_call_seq race in call_mcp_bridge. Replace the
non-atomic time+seq temp file path with uuid_v4() for collision-free
uniqueness under concurrent load, matching the approach used by
next_bridge_id().

Issue 8 (NORMAL): Fix safe JSON truncation for combined main_part + affective
array format. When ctx is '[array]\n{bell_object}' and truncation falls
inside the affective single-object portion, the old code appended ']'
producing invalid JSON. Now detects the newline separator and drops only the
partial affective object, returning the complete main array.

Issue 9 (NORMAL): Handle 4th+ topics in engram_compile. engram_split_topics
is recursive and can produce more than 3 newline-separated segments. Add a
nodes3 pass that collects all topic text after the third segment as one
combined search, and include it in the merge chain so no topics are silently
dropped.

chat.el

@@ -119,7 +119,32 @@ fn engram_compile_ranked(nodes_json: String, max_nodes: Int) -> String {
     let c12: String = str_replace(c11, "\"_sel_12\":1,", "")
     let c13: String = str_replace(c12, "\"_sel_13\":1,", "")
     let c14: String = str_replace(c13, "\"_sel_14\":1,", "")
-    return c14
+    let c15: String = str_replace(c14, "\"_sel_15\":1,", "")
+    let c16: String = str_replace(c15, "\"_sel_16\":1,", "")
+    let c17: String = str_replace(c16, "\"_sel_17\":1,", "")
+    let c18: String = str_replace(c17, "\"_sel_18\":1,", "")
+    let c19: String = str_replace(c18, "\"_sel_19\":1,", "")
+    let c20: String = str_replace(c19, "\"_sel_20\":1,", "")
+    let c21: String = str_replace(c20, "\"_sel_21\":1,", "")
+    let c22: String = str_replace(c21, "\"_sel_22\":1,", "")
+    let c23: String = str_replace(c22, "\"_sel_23\":1,", "")
+    let c24: String = str_replace(c23, "\"_sel_24\":1,", "")
+    let c25: String = str_replace(c24, "\"_sel_25\":1,", "")
+    let c26: String = str_replace(c25, "\"_sel_26\":1,", "")
+    let c27: String = str_replace(c26, "\"_sel_27\":1,", "")
+    let c28: String = str_replace(c27, "\"_sel_28\":1,", "")
+    let c29: String = str_replace(c28, "\"_sel_29\":1,", "")
+    let c30: String = str_replace(c29, "\"_sel_30\":1,", "")
+    let c31: String = str_replace(c30, "\"_sel_31\":1,", "")
+    let c32: String = str_replace(c31, "\"_sel_32\":1,", "")
+    let c33: String = str_replace(c32, "\"_sel_33\":1,", "")
+    let c34: String = str_replace(c33, "\"_sel_34\":1,", "")
+    let c35: String = str_replace(c34, "\"_sel_35\":1,", "")
+    let c36: String = str_replace(c35, "\"_sel_36\":1,", "")
+    let c37: String = str_replace(c36, "\"_sel_37\":1,", "")
+    let c38: String = str_replace(c37, "\"_sel_38\":1,", "")
+    let c39: String = str_replace(c38, "\"_sel_39\":1,", "")
+    return c39
 }
 
 // engram_split_topics — split message into sub-queries on explicit conjunctions.
@@ -170,9 +195,11 @@ fn engram_extract_entities(message: String) -> String {
         let already_have: Bool = str_contains(entities, word)
         let should_add: Bool = is_capital && !is_stop && !already_have && word_len >= 3
         let entities = if should_add {
-            let entity_count = entity_count + 1
             if str_eq(entities, "") { word } else { entities + "\n" + word }
         } else { entities }
+        // Increment entity_count at the while-body level so the binding escapes the
+        // if-expression scope and the entity_count < 10 guard actually terminates early.
+        let entity_count = if should_add { entity_count + 1 } else { entity_count }
         let pos = if wend > pos { wend + 1 } else { pos + 1 }
     }
     return entities
@@ -201,10 +228,12 @@ fn engram_detect_recall_intent(message: String) -> Bool {
         || str_contains(message, "what happened with")
 }
 
-// engram_is_continuation — semantic continuation detection replacing the brittle 50-char
-// threshold. Returns true when message starts with a pronoun, continuation opener, or is
-// < 80 chars (raised from 50 to catch "Can you remind me what Prism's architecture
-// looks like?" at 57 chars which is clearly a continuation in an active thread).
+// engram_is_continuation — detect whether a message continues the active thread.
+// Returns true only when the message starts with a pronoun or an unambiguous
+// discourse continuation marker. Does NOT classify by message length: short messages
+// that introduce a new topic (e.g. "What is quantum computing?") are not continuations.
+// Does NOT classify interrogative starters (How, Why, When, Where, What about) as
+// continuations — these commonly open new topics and the false-positive cost is too high.
 fn engram_is_continuation(message: String, hist_len: Int) -> Bool {
     if hist_len <= 0 { return false }
     let has_pronoun: Bool = str_starts_with(message, "It ")
@@ -216,6 +245,7 @@ fn engram_is_continuation(message: String, hist_len: Int) -> Bool {
         || str_starts_with(message, "She ") || str_starts_with(message, "she ")
         || str_starts_with(message, "We ") || str_starts_with(message, "we ")
     if has_pronoun { return true }
+    // Only unambiguous discourse connectors that cannot open a new topic on their own.
     let is_cont_opener: Bool = str_starts_with(message, "Go on")
         || str_starts_with(message, "go on")
         || str_starts_with(message, "Continue") || str_starts_with(message, "continue")
@@ -224,12 +254,7 @@ fn engram_is_continuation(message: String, hist_len: Int) -> Bool {
         || str_starts_with(message, "Ok") || str_starts_with(message, "ok")
         || str_starts_with(message, "And ") || str_starts_with(message, "and ")
         || str_starts_with(message, "But ") || str_starts_with(message, "but ")
-        || str_starts_with(message, "What about") || str_starts_with(message, "what about")
-        || str_starts_with(message, "Why ") || str_starts_with(message, "why ")
-        || str_starts_with(message, "How ") || str_starts_with(message, "how ")
-        || str_starts_with(message, "When ") || str_starts_with(message, "when ")
     if is_cont_opener { return true }
-    if str_len(message) < 80 { return true }
     return false
 }
 
@@ -306,6 +331,26 @@ fn engram_compile(intent: String) -> String {
         }
     } else { "" }
 
+    // Fourth+ topic segments: engram_split_topics is recursive and can produce 4+ lines.
+    // Rather than hardcoding each topic index, collect everything after the third topic
+    // as a single combined search query so no segments are silently dropped.
+    // This handles inputs like "a and b and c and d" (4 topics).
+    let nodes3: String = if has_multi_topic {
+        let nl0: Int = str_index_of(topics, "\n")
+        let rest1: String = str_slice(topics, nl0 + 1, str_len(topics))
+        let nl1: Int = str_index_of(rest1, "\n")
+        if nl1 < 0 { "" } else {
+            let rest2: String = str_slice(rest1, nl1 + 1, str_len(rest1))
+            let nl2: Int = str_index_of(rest2, "\n")
+            if nl2 < 0 { "" } else {
+                // Remainder after the third segment — may span one or more topics.
+                // Search with the remaining text as-is; engram_compile_multi handles it.
+                let rest3: String = str_slice(rest2, nl2 + 1, str_len(rest2))
+                if str_eq(rest3, "") { "" } else { engram_compile_multi(rest3) }
+            }
+        }
+    } else { "" }
+
     // Issue 2 cont.: entity 0 dedicated search (15 candidates, ranked 6).
     let entity_nodes0: String = if has_entities {
         let nl_e0: Int = str_index_of(entity_list, "\n")
@@ -342,6 +387,7 @@ fn engram_compile(intent: String) -> String {
     // Merge all pools, deduplicating at each step.
     let merged: String = engram_nodes_merge(nodes0, nodes1)
     let merged: String = engram_nodes_merge(merged, nodes2)
+    let merged: String = engram_nodes_merge(merged, nodes3)
     let merged: String = engram_nodes_merge(merged, entity_nodes0)
     let merged: String = engram_nodes_merge(merged, entity_nodes1)
     let merged: String = engram_nodes_merge(merged, recall_boost)
@@ -388,8 +434,16 @@ fn engram_compile(intent: String) -> String {
 
     if str_eq(ctx, "") { return "" }
 
-    // Issue 7 fix: safe JSON truncation — find last closing brace before budget cap.
+    // Safe JSON truncation — find last closing brace before budget cap.
     // Budget raised from 6000 to 8000 for the larger multi-topic pool.
+    //
+    // Issue 8 fix: ctx may be main_part (JSON array) + "\n" + affective_part (single JSON
+    // object). When truncation cuts into the affective_part, appending "]" would produce
+    // "[array_content]{partial_bell_node}]" — not valid JSON. Guard: only append "]" when
+    // the truncation point falls strictly within the main array portion (before the "\n"
+    // separator). If the cut falls in the affective part, drop the partial object entirely
+    // and return only the complete main array. If there is no separator (ctx is a plain
+    // array with no affective part), the original append-"]" behaviour applies.
     let budget: Int = 8000
     if str_len(ctx) <= budget { return ctx }
     let search_end: Int = budget - 1
@@ -403,7 +457,18 @@ fn engram_compile(intent: String) -> String {
     }
     if found_pos < 0 { return str_slice(ctx, 0, budget) }
     let truncated: String = str_slice(ctx, 0, found_pos + 1)
-    if str_starts_with(ctx, "[") { return truncated + "]" }
+    if str_starts_with(ctx, "[") {
+        // Determine whether this ctx has a separate affective object appended after the array.
+        // The format is: main_array + "\n" + bell_object. Find the array boundary.
+        let nl_pos: Int = str_index_of(ctx, "\n")
+        let has_affective_sep: Bool = nl_pos > 0 && nl_pos < str_len(ctx) - 1
+        if has_affective_sep && found_pos > nl_pos {
+            // Truncation fell inside the affective_part — drop it and return just the main array.
+            return str_slice(ctx, 0, nl_pos)
+        }
+        // Truncation is within the main array — close it properly.
+        return truncated + "]"
+    }
     return truncated
 }
 fn json_safe(s: String) -> String {
@@ -505,23 +570,19 @@ fn hist_trim(hist: String) -> String {
 // a bell event. If it did, write a preservation node to engram so the distress exchange
 // survives the 20-turn window. The LLM window drops it; engram retains it permanently
 // and engram_compile will surface it again via the affective context path.
+//
+// Fix: use json_array_get for structural parsing (immune to {"role": appearing in
+// message content) — same fix applied to hist_trim. The old str_index_of("{\"role\":")
+// pattern could corrupt history when any message contained that literal string.
 fn hist_trim_with_bell_guard(hist: String) -> String {
-    // Extract the first turn (should be a user message) to inspect it.
-    let inner: String = str_slice(hist, 1, str_len(hist) - 1)
-    let marker: String = "{\"role\":"
-    let i1: Int = str_index_of(inner, marker)
-    // i1 is the start of the first entry within inner.
-    // Find where the second entry begins to delimit the first entry's JSON.
-    let tail1: String = str_slice(inner, i1 + 1, str_len(inner))
-    let i2: Int = str_index_of(tail1, marker)
-    // The first entry spans from i1 to (i1 + 1 + i2 - 1) within inner.
-    let first_entry_raw: String = if i2 > 0 {
-        str_slice(inner, i1, i1 + 1 + i2 - 1)
-    } else {
-        str_slice(inner, i1, str_len(inner))
-    }
-    let first_role: String = json_get(first_entry_raw, "role")
-    let first_content: String = json_get(first_entry_raw, "content")
+    let total: Int = json_array_len(hist)
+    // Safety: never trim below 2 entries.
+    if total <= 2 { return hist }
+
+    // Extract the first entry structurally — immune to content containing {"role":
+    let first_entry: String = json_array_get(hist, 0)
+    let first_role: String = json_get(first_entry, "role")
+    let first_content: String = json_get(first_entry, "content")
 
     // Only inspect user turns — assistant content doesn't carry bell signals.
     let bell_level: String = if str_eq(first_role, "user") {
@@ -554,13 +615,9 @@ fn hist_trim_with_bell_guard(hist: String) -> String {
         )
     }
 
-    // Now perform the standard trim (drop oldest 2 entries = 1 user + 1 assistant pair).
-    let tail2: String = str_slice(tail1, i2 + 1, str_len(tail1))
-    let i3: Int = str_index_of(tail2, marker)
-    if i3 >= 0 {
-        return "[" + str_slice(tail2, i3, str_len(tail2)) + "]"
-    }
-    return hist
+    // Now perform the standard trim: drop entries 0 and 1 (oldest user+assistant pair).
+    // Reuse hist_trim's structural approach — rebuild from entry 2 onward.
+    return hist_trim(hist)
 }
 
 // clean_llm_response — strips GPT-2 BPE byte-to-unicode artifacts that vLLM
@@ -1022,15 +1079,11 @@ fn agentic_tools_all() -> String {
 fn call_mcp_bridge(tool_name: String, tool_input: String) -> String {
     let eff_input: String = if str_eq(tool_input, "") { "{}" } else { tool_input }
     let body: String = "{\"name\":\"" + tool_name + "\",\"input\":" + eff_input + "}"
-    // Issue #12: previously used a fixed path /tmp/neuron-mcp-call.json.
-    // Under concurrent load (64 worker threads), two simultaneous MCP tool calls
-    // race on this file — one call sends the other's input to the bridge.
-    // Fix: monotonic sequence counter makes the path unique per call.
-    let mcp_seq_s: String = state_get("mcp_call_seq")
-    let mcp_seq_n: Int = if str_eq(mcp_seq_s, "") { 0 } else { str_to_int(mcp_seq_s) }
-    let mcp_seq_next: Int = mcp_seq_n + 1
-    state_set("mcp_call_seq", int_to_str(mcp_seq_next))
-    let tmp: String = "/tmp/neuron-mcp-call-" + int_to_str(time_now()) + "-" + int_to_str(mcp_seq_next) + ".json"
+    // Issue #12: previously used a fixed path /tmp/neuron-mcp-call.json, then a
+    // time+seq path that still raced (time_now() is 1s granularity; non-atomic seq RMW).
+    // Fix: uuid_v4() provides collision-free uniqueness regardless of concurrency —
+    // same approach used by next_bridge_id(). No state read/write needed.
+    let tmp: String = "/tmp/neuron-mcp-call-" + uuid_v4() + ".json"
     fs_write(tmp, body)
     return exec_capture("curl -s --max-time 30 -X POST http://127.0.0.1:7771/mcp/call -H 'Content-Type: application/json' -d @" + tmp)
 }
@@ -1374,7 +1427,7 @@ fn handle_chat_agentic(body: String) -> String {
     let session_valid: Bool = if str_eq(req_session, "") {
         true
     } else {
-        !str_contains(session_get(req_session), "\"error\"")
+        session_exists(req_session)
     }
     if !session_valid {
         return "{\"error\":\"session not found\",\"session_id\":\"" + req_session + "\",\"reply\":\"\"}"
@@ -2014,6 +2067,7 @@ fn auto_persist(req: String, resp: String) -> Void {
             "session_bell_signal:" + sess_id
         }
         state_set(signal_key, safe_summary)
+    }
     if str_eq(conv_node_id, "") {
         println("[chat] auto_persist: engram_node_full returned empty — conversation node lost (ts=" + ts_str + ")")
     }