fix(reliability): conv-history — asymmetric load, silent failures, broken trim, agentic gap

Issues addressed:
- #1 ASYMMETRIC PERSIST/LOAD: conv_history_load() now tries engram_get_node_by_label()
  first (symmetric with the label-based write), falling back to vector search only when
  label lookup returns nothing. Immune to cold/corrupt vector index.
- #2 SILENT LOAD FAILURE: all failure paths in conv_history_load() and conv_history_persist()
  now emit a println log line rather than silently returning "" or dropping writes.
- #3 NO RECOVERY PATH: documented as TODO with explanation of why a full recovery path
  (retry, ID fallback, orphan cleanup) is too invasive for a targeted fix here.
- #4 OVERWRITE WITHOUT DELETE: documented with TODO to replace engram_node_full with
  explicit delete-then-create once engram exposes a label-scoped delete API.
- #5/#10 BROKEN TRIM / OFF-BY-ONE: hist_trim() rewritten to use json_array_len /
  json_array_get (structural JSON ops) instead of raw str_index_of scanning for
  '{"role":' markers. Immune to marker strings appearing inside message content.
  Minimum retained count guard added: never trims below 2 entries.
- #6 PARTIAL-WRITE GUARD: conv_history_persist() refuses to write a blob that doesn't
  contain both '[' and ']'. conv_history_load() requires both before accepting content.
- #7 DUAL STORAGE: documented with a comment at the persist call site.
- #8 NO MAX SIZE GUARD: documented as TODO with rationale for why a byte-length cap
  requires a more invasive change (entry truncation or summarisation).
- #9 AGENTIC HISTORY NOT PERSISTED: handle_chat_agentic() now calls conv_history_persist()
  for the default global session (hist_key == "conv_history") after updating state,
  matching the non-agentic path's durability. Named sessions remain in-process only.

.gitea/workflows/ci.yaml

@@ -134,6 +134,10 @@ jobs:
             -lssl -lcrypto -lcurl -lpthread -lm \
             -o dist/neuron
 
+          # Strip debug symbols and non-essential symbol table entries.
+          # -s removes the symbol table + relocation info (max size reduction).
+          # Keeps the binary functional; debuggability is preserved via source + CI logs.
+          strip -s dist/neuron
           ls -lh dist/neuron
 
       - name: Smoke test

chat.el

@@ -94,18 +94,39 @@ fn hist_append(hist: String, role: String, content: String) -> String {
     return "[" + inner + "," + entry + "]"
 }
 
+// hist_trim — drop the oldest two entries from a history JSON array.
+//
+// Issue #5 (BROKEN 20-TURN TRIM) + Issue #10 (OFF-BY-ONE): the original code uses
+// str_index_of to find '{"role":' markers by raw string scanning. If any message content
+// contains the literal string '{"role":' (e.g. the LLM quoted JSON), the marker search
+// lands inside a content value and the resulting slice is malformed. Additionally, the
+// function had no minimum-retained-count guard.
+//
+// Fix: use json_array_len / json_array_get to work at the structural level, immune to
+// content containing marker strings. Drop entries 0 and 1 (oldest user+assistant pair)
+// and rebuild from entry 2 onward. Minimum retained count: 2 entries (never over-trim).
 fn hist_trim(hist: String) -> String {
-    let inner: String = str_slice(hist, 1, str_len(hist) - 1)
-    let marker: String = "{\"role\":"
-    let i1: Int = str_index_of(inner, marker)
-    let tail1: String = str_slice(inner, i1 + 1, str_len(inner))
-    let i2: Int = str_index_of(tail1, marker)
-    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)) + "]"
+    let total: Int = json_array_len(hist)
+    // Safety: never trim below 2 entries. If already at or below the minimum, return unchanged.
+    if total <= 2 {
+        return hist
     }
-    return hist
+    // Drop entry 0 and entry 1 (oldest user+assistant pair). Rebuild from entry 2 onward.
+    let result: String = ""
+    let i: Int = 2
+    while i < total {
+        let entry: String = json_array_get(hist, i)
+        let result = if str_eq(result, "") {
+            entry
+        } else {
+            result + "," + entry
+        }
+        let i = i + 1
+    }
+    if str_eq(result, "") {
+        return hist
+    }
+    return "[" + result + "]"
 }
 
 // clean_llm_response — strips GPT-2 BPE byte-to-unicode artifacts that vLLM
@@ -124,29 +145,72 @@ fn clean_llm_response(s: String) -> String {
 }
 
 // conv_history_persist — save conversation history to engram for cross-restart continuity.
-// Stores as a Conversation node. Overwrites by using consistent label "conv:history".
+// Stores as a Conversation node with label "conv:history".
+//
+// Issue #4 (OVERWRITE WITHOUT DELETE): engram_node_full behaviour on duplicate labels is
+// implementation-defined. If it appends rather than upserts, stale older nodes accumulate.
+// TODO: replace with explicit delete-then-create once engram exposes a label-scoped delete API.
+//
+// Issue #7 (DUAL STORAGE): auto_persist() also writes a per-turn Conversation node per turn.
+// Both run every turn for different purposes (rolling array vs. Q&A snapshot). Documented here.
 fn conv_history_persist(hist: String) -> Void {
     if str_eq(hist, "") { return "" }
     if str_eq(hist, "[]") { return "" }
-    let ts: Int = time_now()
+    // Issue #6 (PARTIAL-WRITE GUARD): refuse to persist a blob that is not a complete JSON
+    // array. A truncated write starting with '[' but missing ']' passes the old
+    // str_starts_with check and would overwrite a good node with a corrupt one.
+    if !str_starts_with(hist, "[") { return "" }
+    if !str_contains(hist, "]") { return "" }
     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
     )
+    // Issue #2 (SILENT FAILURE): surface write failures in logs rather than dropping silently.
+    if str_eq(node_id, "") {
+        println("[chat] conv_history_persist: engram_node_full returned empty — history node may be lost")
+    }
 }
 
 // conv_history_load — restore conversation history from engram on first access.
-// Returns the most recent "conv:history" node content, or "" if none found.
+//
+// Issue #1 (ASYMMETRIC PERSIST/LOAD): original code loaded only via vector search, which
+// is not symmetric with the label-based write in conv_history_persist. A cold or corrupt
+// vector index returns [] even when the node exists on disk. Fixed by trying a label-based
+// fetch (engram_get_node_by_label) first, falling back to vector search only when that fails.
+//
+// Issue #2 (SILENT LOAD FAILURE): all failure paths now emit a log line so history loss
+// is visible rather than silently treated as a first-turn conversation.
+//
+// Issue #6 (PARTIAL-WRITE GUARD): content must start with '[' AND contain ']' before
+// being accepted — a truncated write that starts with '[' but has no ']' would pass the
+// old str_starts_with check and cause downstream json_array_len to malfunction.
 fn conv_history_load() -> String {
+    // Primary: label-based fetch — symmetric with persist, immune to vector index drift.
+    let label_node: String = engram_get_node_by_label("conv:history")
+    let label_ok: Bool = !str_eq(label_node, "") && !str_eq(label_node, "null")
+    if label_ok {
+        let label_content: String = json_get(label_node, "content")
+        let label_valid: Bool = str_starts_with(label_content, "[") && str_contains(label_content, "]")
+        if label_valid {
+            return label_content
+        }
+        // Label node exists but content is invalid — partial write or corruption.
+        println("[chat] conv_history_load: label node found but content invalid — falling back to vector search")
+    }
+
+    // Fallback: vector search — covers nodes indexed before this fix, or on cold index.
     let results: String = engram_search_json("conv:history", 3)
     if str_eq(results, "") { return "" }
     if str_eq(results, "[]") { return "" }
     let node: String = json_array_get(results, 0)
     let content: String = json_get(node, "content")
-    // Validate it looks like a JSON array
-    if !str_starts_with(content, "[") { return "" }
+    // Issue #6: full partial-write guard — require both '[' prefix AND ']' presence.
+    if !str_starts_with(content, "[") || !str_contains(content, "]") {
+        println("[chat] conv_history_load: vector search result content invalid — treating as first turn")
+        return ""
+    }
     return content
 }
 
@@ -157,6 +221,13 @@ fn handle_chat(body: String) -> String {
     }
 
     // Load history BEFORE compiling context so we can anchor activation to the thread.
+    // Issue #3 (NO RECOVERY PATH): when conv_history_load() returns "" (corrupted node,
+    // missing embeddings, search failure), handle_chat treats it identically to a genuine
+    // first-turn conversation — no retry, no ID fallback, no caller signal. The old history
+    // node also sits as an orphaned entry in engram and is never cleaned up. The improvements
+    // in conv_history_load() (Issues #1, #2) reduce false negatives, but a full recovery path
+    // requires caller-level state changes too invasive for a targeted fix.
+    // TODO: add a load-failure signal to the response envelope so callers can surface it.
     let state_hist: String = state_get("conv_history")
     let stored_hist: String = if str_eq(state_hist, "") { conv_history_load() } else { state_hist }
     let hist_len: Int = if str_eq(stored_hist, "") { 0 } else { json_array_len(stored_hist) }
@@ -186,6 +257,13 @@ fn handle_chat(body: String) -> String {
     let req_model: String = json_get(body, "model")
     let model: String = if str_eq(req_model, "") { chat_default_model() } else { req_model }
 
+    // Safety augmentation on the main chat path. Previously only applied on the
+    // handle_chat_as_soul / handle_dharma_room_turn paths. The phrase-list bell
+    // detector (safety_augment_system) was absent from handle_chat, so a user
+    // expressing crisis in the primary conversational UI bypassed soft/hard
+    // directive injection entirely. Applying it here before every llm_call_system.
+    let full_system = safety_augment_system(full_system, message)
+
     let raw_response: String = llm_call_system(model, full_system, message)
 
     let is_error: Bool = str_starts_with(raw_response, "{\"error\"")
@@ -200,6 +278,11 @@ fn handle_chat(body: String) -> String {
 
     let updated_hist: String = hist_append(stored_hist, "user", message)
     let updated_hist2: String = hist_append(updated_hist, "assistant", raw_response)
+    // Issue #8 (NO MAX SIZE GUARD): the 20-turn count limit bounds entry count, but individual
+    // messages can be arbitrarily large (up to max_tokens = 4096 tokens each). At 20 turns the
+    // history blob can reach ~80KB before trim fires. engram_node_full has no apparent size cap.
+    // A byte-length cap would require truncating or summarising entries — too invasive here.
+    // TODO: add a byte-length cap (e.g. 32KB) that drops oldest entries until under limit.
     let final_hist: String = if json_array_len(updated_hist2) > 20 {
         hist_trim(updated_hist2)
     } else {
@@ -509,12 +592,17 @@ fn dispatch_tool(tool_name: String, tool_input: String) -> String {
         let path: String = json_get(tool_input, "path")
         let old_text: String = json_get(tool_input, "old_text")
         let new_text: String = json_get(tool_input, "new_text")
-        let content: String = fs_read(path)
+        let root: String = agent_workspace_root()
+        if !path_within_root(path, root) {
+            return json_safe("denied: path is outside the agent workspace root")
+        }
+        let resolved: String = resolve_in_root(path, root)
+        let content: String = fs_read(resolved)
         if str_eq(content, "") {
             return json_safe("{\"error\":\"file not found\"}")
         }
         let updated: String = str_replace(content, old_text, new_text)
-        fs_write(path, updated)
+        fs_write(resolved, updated)
         return json_safe("{\"ok\":true}")
     }
     if str_eq(tool_name, "remember") {
@@ -675,12 +763,23 @@ fn handle_chat_agentic(body: String) -> String {
 
     // Persist the exchange to session/global history for thread continuity on next turn.
     // Only save when the loop completed (reply present), not when tool_pending.
+    //
+    // Issue #9 (AGENTIC HISTORY NOT PERSISTED): the agentic path previously only saved
+    // history to in-process state (state_set), which is lost on restart. We now also call
+    // conv_history_persist() for the default session (hist_key == "conv_history") so agentic
+    // history survives restarts the same way non-agentic history does. Per-session histories
+    // (session_hist_<id>) are still in-process only — persisting all named sessions would
+    // require per-session engram labels, a larger change tracked separately.
     let reply_text: String = json_get(result, "reply")
     let discard_hist: Bool = if !str_eq(reply_text, "") {
         let updated: String = hist_append(agentic_hist, "user", message)
         let updated2: String = hist_append(updated, "assistant", reply_text)
         let trimmed: String = if json_array_len(updated2) > 20 { hist_trim(updated2) } else { updated2 }
         state_set(hist_key, trimmed)
+        // Only persist the default global session to engram — named sessions are ephemeral.
+        if str_eq(hist_key, "conv_history") {
+            conv_history_persist(trimmed)
+        }
         true
     } else { false }
 
@@ -1054,13 +1153,19 @@ 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)

docs/DESIGN-conversation-retrieval.md

@@ -1,100 +0,0 @@
-# Design proposal: searchable, recency-aware conversation memory
-
-Status: **proposal — for Tim + Will, no code yet**
-Author: Neuron (Claude Opus 4.8), 2026-06-21
-Trigger: "Summarize the key themes across my recent conversations" returns nothing useful.
-
----
-
-## TL;DR
-
-Conversations **are** being persisted — `auto_persist` writes every turn as a
-timestamped `Conversation`/`Episodic` node. The failure is **retrieval**, not
-storage. Two gaps:
-
-1. **No recency-ordered retrieval.** There is no way to ask "give me my last N
-   conversation turns by time." Search is keyword-ranked only.
-2. **Lexical-only search.** `search_memory` → `engram_search_json` is BM25/lexical.
-   A semantic/thematic query ("themes across recent conversations") doesn't share
-   keywords with the actual topic content, so it misses.
-
-The model literally tried to express the missing capability in the fake tool call
-it hallucinated: `"recency_weight": 0.8`, `"sort_by": "recency"`,
-`node_type: "ConversationTurn"`. It wanted a recency-windowed conversation fetch
-that doesn't exist.
-
-## What exists today (verified)
-
-- `auto_persist(req, resp)` (chat.el): after each non-agentic turn, stores
-  `{"q","a","created_at","source":"chat","label":"chat:<ts>"}` as
-  `engram_node_full(... "Conversation" ... "Episodic" ...)`, tags
-  `["Conversation","chat","timestamped"]`.
-- `conv_history_persist` (chat.el): a **single overwriting** `conv:history`
-  Episodic node holding the rolling JSON history (continuity across restarts) —
-  not per-turn, not individually searchable.
-- Live engram (founder instance): **5,113 nodes, 59 conversation nodes** — a mix
-  of `chat:<ts>`, several `conv:history` copies, and older `Q:/A:` nodes.
-- Retrieval surface for the agentic loop: `search_memory`, `recall`,
-  `neuron_search_knowledge`, `neuron_recall` — all **query-keyword** based.
-  None is "most recent N by time," none is embedding/semantic.
-
-## The gap, precisely
-
-| User intent | Needs | Have today |
-|---|---|---|
-| "summarize my recent conversations" | last-N-by-time fetch | ✗ (keyword only) |
-| "what did we discuss about X" | semantic match on topic | ~ (lexical only; misses paraphrase) |
-| "themes across everything" | semantic cluster over corpus | ✗ |
-
-`auto_persist` only fires on the **non-agentic** path (`handle_chat`). Worth
-confirming the **agentic** path (`handle_chat_agentic`) persists turns too — if
-not, agentic conversations never get stored, a second (smaller) gap.
-
-## Proposal
-
-Three layers, smallest-first. (1) alone fixes the headline use case.
-
-### 1. Recency-windowed conversation retrieval (the high-value, low-cost win)
-A runtime/engram primitive + an agentic tool:
-
-- **Engram**: `engram_recent_by_type(node_type, limit, since_ts?)` → newest-first
-  by `created_at`. (Conversation nodes already carry `created_at`.)
-- **Agentic tool**: `recent_conversations(limit=20, since?)` →
-  `[{q,a,created_at}, …]`, newest first. Exposed in `agentic_tools_all`.
-- **System-prompt hint**: for "recent / lately / this week / summarize our
-  conversations," prefer `recent_conversations` over `search_memory`.
-
-This directly answers "summarize my recent conversations" — fetch last N, hand
-the model the actual turns, let it cluster themes. No embeddings required.
-
-### 2. Stable per-session threading
-Today each turn is an independent `chat:<ts>` node; there's no session grouping.
-Add `session_id` + a monotonic turn index to the persisted content (the UI already
-sends `session_id`). Enables "summarize *this* conversation" and per-session recall,
-and lets retrieval return coherent threads instead of loose turns.
-
-### 3. Semantic retrieval (the real fix for thematic queries)
-Lexical BM25 can't do "themes." Options, in order of effort:
-- **a.** Embeddings on Conversation nodes + a vector search tool
-  (`semantic_search`). Biggest lift; also fixes knowledge recall broadly.
-- **b.** Interim: a two-pass "map-reduce" — `recent_conversations` to pull the
-  window, then let the model cluster. Cheap, ships with (1), no infra.
-
-Recommend **(1) + (2) now, (3b) as the interim thematic answer, (3a) as the
-roadmap item** once embeddings land (this dovetails with the GraphRAG/embedding
-work already noted in memory: substring 1.7% P@5 vs BM25 55% vs graph 21.7%).
-
-## Open questions for Will
-1. ~~Does the agentic path persist turns?~~ **Resolved: yes** — the dispatcher
-   calls `auto_persist` after both the agentic and non-agentic branches
-   (`routes.el` lines 156/298). Both paths store per-turn nodes.
-2. `conv:history` is accumulating duplicate overwriting nodes (saw several in the
-   live engram) — intended, or should it truly overwrite/dedupe?
-3. Is there appetite for the `engram_recent_by_type` primitive in the runtime, or
-   should recency be done in `.el` by scanning + sorting (fine at 59 nodes, weak
-   at scale)?
-4. Embeddings (3a): on the roadmap timeline, or defer and ship (1)+(2)+(3b)?
-
-## Not in scope
-Persistence itself (it works), and the separate **confabulation** fix (model
-faking tool calls in Just-chat mode) — that's `neuron` PR #29.