Stop hand-rolling GPU kernels for batch cosine similarity — use ggml (the
MIT-licensed compute library underneath llama.cpp, installed standalone via
Homebrew) as the preferred backend, without ripping out PR #114's
carefully-verified hand-rolled Metal shader.
Structure: one stable public adapter (eg_cosine_batch.h, zero #ifdef at call
sites) backed by three selectable concrete Strategies behind an internal
vtable (eg_cosine_batch_strategy.h) chosen by a Factory (eg_cosine_batch.c):
- eg_cosine_batch_strategy_ggml.c — NEW. ggml + dynamically-loaded Metal
backend plugin (ggml_backend_load_all_from_path
+ ggml_mul_mat for the batched dot
product), gather/scatter around the
-2.0 sentinel contract.
- eg_cosine_batch_strategy_metal_hand.m — PR #114's original hand-rolled
Metal shader bridge, preserved
almost verbatim, now one strategy
among several rather than the only
option. eg_cosine_batch.metal kept
byte-identical to the original.
- eg_cosine_batch_strategy_cpu.c — universal always-false fallback
(direct descendant of PR #114's
eg_metal_cosine_stub.c).
Selection: EL_COSINE_BATCH_STRATEGY=ggml|metal|cpu|auto (default: ggml first,
then hand-rolled Metal, then CPU — first available wins), plus back-compat
EL_METAL_COSINE=0 to disable every GPU-backed strategy. build_vindex_bench.sh
compiles all three strategies on Darwin, CPU-fallback-only elsewhere.
vindex_bench.c now reports BRUTE-GGML and BRUTE-METAL side by side against
the same CPU oracle, on the same dataset, in one run (real numbers vs. real
store snapshot in the PR body).
Lands feat/reframe-region-setop (PR #109: native set-based reframe_region,
decorator-as-seam @route port, teacher-summon, and the M8.1 activate-latency
work — lazy-memoized cosq via eg_cosq_at + engram_vindex HNSW-accelerated
seed discovery + vindex_harvest_from_store/vindex_bench oracle) onto dev's
actual current HEAD, plus engram-tiered-storage's still-unique test suite.
RECONCILING #109 WITH engram-tiered-storage (M4-M10 HNSW/geometry/reason/
verify work): not a two-way merge. engram_vindex.c's HNSW core (search_layer/
select_neighbors/prune_links/insert) is BYTE-IDENTICAL between the two
branches; #109's copy is a strict superset (adds vindex_harvest_from_store,
used by vindex_bench.c's brute-force-vs-HNSW oracle). engram_reason.c and
engram_verify.c are also byte-identical. #109's own branch point already
carried engram-tiered-storage's M4-M10 lineage forward, so there was nothing
left to merge into #109 for those files. The one thing engram-tiered-storage
had that #109's tree dropped: its full test suite (test_vindex.c,
test_geometry.c, test_reason.c, test_verify.c, test_m7_traversal.c, the
interoception P0-P5 tests, bufpool/compaction tests, and their run_*.sh
harnesses) — ported over here unchanged.
WHY THIS NEEDED HAND RECONCILIATION, NOT A MECHANICAL MERGE: #109's branch
forked from dev on 2026-08-14 15:40 (before restructure-adjacent history
diverged the file's merge-base for `git merge` — it presented as an add/add
conflict). A straight two-dot diff (dev tip -> PR tip) applied cleanly, but
it silently reverted THREE dev fixes landed on 2026-08-14/15, after the
branch point, that the PR's diff had no way to know about:
1. qgate rescale (2026-08-14 self-review): PR's lazy eg_cosq_at rewrite of
the query-aware propagation gate dropped the shift-and-floor rescale
about ENGRAM_EMBED_S0 (measured: unrelated-pair median 0.562->raw gate
0.67, i.e. "a small tax, not a gate"). Restored the rescale, wrapped
around the lazy accessor -- the PR's actual improvement (WHEN cosq[oi]
is computed) is orthogonal to WHAT it gates on and both are kept.
2. Eviction cause decomposition (2026-08-14 self-review): dev decomposes
wm_evicted into evict_floor/evict_cap/evict_bll so WM churn is
diagnosable (identity: evicted == floor+cap+bll+dup_wm+dup_wm_global).
PR's tree predates this and dropped all three counters + their JSON
stats fields. Restored declarations, all 4 direct increment sites, the
eg_wm_carry_over bll increment, and the act-stats JSON fields --
alongside (not instead of) the PR's own P4 afferent / API-reshape
counters already in that same struct/JSON.
3. Hebbian link-formation selection (2026-08-15 self-review, TODAY): dev
selects the STRONGEST qualifying candidate for consolidation each call;
PR's tree predates this and reverted to hash-slot order (arbitrary wrt
association strength) for edge formation -- the one path that writes
PERMANENT structure. Restored the strongest-candidate while-loop,
keeping the PR's own genuine improvement at that site
(engram_adj_on_edge_added incremental-index append instead of a bare
adj_dirty=1 full-rebuild flag).
engram/src/server.el's 3-way conflicts (autoconnect_on/ise_offgraph_on env
flags, /api/nodes connected-count in responses) were pure additive: dev's
side was empty, PR's side added the feature. Took PR's side whole.
VERIFIED (nsbx sandbox only, live :8742/:7770 never touched):
- cc -std=c11 -O2, clean link against the real engram/src/server.el via
elc, zero errors.
- vindex_bench (built standalone, read-only harvest) against the real
production store clone (13,671 embedded nodes, 768-dim nomic-embed-text):
recall@10 = 1.0000 at ef 64/128/200; HNSW search 0.28-0.79ms/query vs
2.03ms/query brute-force oracle (2.6x-7.2x). HNSW build itself: 46.5s
for the full 13,671-node set -- see the flagged risk below.
- Booted the reconciled binary in an isolated nsbx sandbox (:8905, cloned
snapshot of the live store, 13,424 nodes / 37,656 edges) and called
/api/activate for real: first call after boot 41.5s (pays the one-time
HNSW build inline -- matches the standalone bench), second/third calls
356ms/605ms, no crash, correct results, act-stats JSON (including the
restored evict_floor/cap/bll fields) reads correctly.
KNOWN RISK TO FLAG BEFORE ANY LIVE CUTOVER (not fixed here; out of scope for
this dev-only land per instructions not to touch :8742/:7770): eg_vindex_sync
builds the HNSW index synchronously, inline, on the first engram_activate()
call after every process start (or index invalidation). On the real node
count that is a ~46s blocking stall on a single-threaded server -- the first
request after every restart (or its concurrent siblings) waits the full
build. Recommend a background/incremental build (or a bounded per-call build
budget) before this ever reaches the live daemon. See PR description / final
report for the fuller writeup.
Adds an O(1) "seen" bitmap so lazily-embedded older nodes get picked up
incrementally instead of only on a full rebuild (embed-gap #20).
Replaces engram_activate's O(N*D) cosine prescan with a lazy-memoized
cosine cache (eg_cosq_at), proven bit-identical to the old path.
Extracts a clean vindex_harvest_from_store primitive (read-only vector
harvest, careful malloc/ownership/error-path handling) reused by both
index-build and the new vindex_bench.c — a read-only proof harness
comparing brute-force vs HNSW recall/latency on both the real store and
synthetic data.
.nsbx-env intentionally excluded — local sandbox config (ports, paths,
dev-only placeholder key), not checked in.
Cancellation-token control channel checked at every step boundary lets a
coordinator PAUSE/RESUME/REDIRECT/KILL a running worker mid-task instead of
waiting for the whole (possibly wrong) plan to finish. Bounded purviews
mean no half-committed state to unwind on interrupt. Includes a proof
harness (proof.el, run.sh) comparing a broken non-interruptible worker
against the new one under identical kill/redirect/pause timing.
Distinct from the already-preserved swarm-ccr orchestrator (fan-out/
converge dispatch): this is single-worker interruptibility, a
complementary mechanism, not a duplicate.
Float + previously fell through to string concat (segfault); -, *, /, %
operated on raw IEEE-754 bit patterns as integers (garbage results). Floats
are now tracked via a __float_names typed-binding set (parallel to the
existing int-tracking scheme) and arithmetic is emitted as real C double
ops.
Also fixes math_log, which was wrongly aliased to natural log (duplicating
math_ln) — now uses log10 — and adds the missing <math.h> include. Rebuilt
elc binary included.
The link-formation scan walked candidate slots ascending and stopped at
ENGRAM_HEBB_LINK_PER_CALL (2). Slot index is a hash of the node id pair, so
whenever more than two candidates cleared LINK_MIN in the same call, the two
consolidated were the two with the lowest hash and a stronger association
waited - indefinitely, since the scan restarts from slot 0 every call while
the leader decays at ENGRAM_HEBB_DECAY.
Measured 08-13..08-15: hebb_cand_max peaked at 0.4963, 3.3x LINK_MIN, during
a ~14h stretch of continuous qualification at the 2/call cap.
Same defect the 2026-08-02 review named and fixed for breakthrough weights
(index order is not a cognitive criterion), never carried across to the one
path that writes permanent structure - and there is no pruning path, so
growth is one-way. Selection pressure matters most where the result is
irreversible.
No-op when <=2 candidates qualify; picks the best when more do.
Will waived diff review -> build it for real. Add engram_boundary_beat() to the
runtime (afferent counter++ + engram_chrono_tick + engram_strengthen(self-anchor)
+ dharma_emit) and two act-stats counters (aff_boundary_ops, dharma_emits).
codegen cg_fn injects ONE engram_boundary_beat(op) at the entry of every
@manager/@accessor fn (fn_has_decorator, so it fires under @route @manager too) —
a decorated op self-reports with ZERO hand-written instrumentation. Rebuilt elc
self-host + the cognition engram in the worktree; ran it as the clone daemon on
:8900. Proof (/api/boundary-proof, @manager, empty body, 5x): aff_boundary_ops
0->5, dharma_emits 0->5, self activation_count 1510->1513, chrono stamp advanced.
Brought in feat/cognitive-architecture engram runtime+server for the build.
strengthen = activation bump (not content/edge write) -> identity protection
intact. Live :8742 untouched; no push, no cutover.
Ground-truth the three seams (route/telemetry+interoception/bus) with file:line
evidence. Port the tested @route codegen+parser from feat/el-route-decorators
into the worktree elc (decoration synthesizes el_route_dispatch — no hand-written
90-branch handle_request). Rebuild elc self-host; prove decorate->serve end-to-end
(route_proof.el on :8951). Rewrite surface.el as El-native decorated components:
@route + @accessor/@manager, in-process engram_* builtins (not http_get), @manager
ops emit on the real dharma_* bus (same transport as wt/swarm-ccr). Identity
keystones refused in write/relate/supersede. Gate-1 clone recipe (WAL-aside
cold-boot + ENGRAM_WAL=on) proves the FULL op set live on the clone. Boundary
auto-emit (telemetry/interoception/bus) staged as a reviewable cg_fn diff
(SEAM_STAGED.md) — needs the cognition-engram rebuild to verify link. Live :8742
untouched; no push, no cutover.
Two changes to the activation path, both grounded in measurement on the live
store rather than on the spec.
1. Rescale cosine before the query gate.
The propagation gate (arXiv:2606.30133, added in an earlier review) fed RAW
cosine into FLOOR + (1-FLOOR)*c. Raw cosine from nomic-embed is compressed
into a narrow high band, so that expression is close to a constant.
Measured, 400 random UNRELATED node pairs on the live store:
median 0.562, central 98% span [0.381, 0.743]
So a node with no semantic relation to the query was propagating at
0.25 + 0.75*0.562 = 0.67. Two thirds strength. The gate was a small tax.
Fixed by shifting and flooring about ENGRAM_EMBED_S0 -- which is already in
this file, already 0.45, and already used exactly this way by the Pass-2 WM
term. The propagation gate simply never used it. Same 400 pairs after:
median unrelated pair falls to 0.40, top of range preserved (0.85 vs 0.92),
gate spread widens 0.42 -> 0.60. Only 8.5% reach the floor, so dissimilar
lexical/structural pathways are damped, never severed. Range is unchanged
at [0.25, 1.0], and cosq == NULL still degrades to no gating at all.
2. Decompose the WM eviction counter by cause.
_eg_act_wm_evicted was incremented from six sites with four distinct causes
and collapsed all of them into one integer. Today's review measured 175,547
evictions over 13.5h (~216/min against 24 slots) and could not tell healthy
rotation from cap thrashing from duplicate churn.
That is this file's most-repeated defect: dup_wm and dup_wm_global exist
only because the aggregate could not answer "why" during the 08-02 and
08-06 incidents. Each of those needed a NEW gauge before it was diagnosable.
evict_floor / evict_cap / evict_bll complete the decomposition, so
wm_evicted == floor + cap + bll + dup_wm + dup_wm_global
holds as an identity and each term implies a different correction. Verified
on an isolated instance: 30 nodes, 24 filled the cap, wm_evicted 6 ==
evict_cap 6, all other terms 0.
Built and smoke-tested out of tree. The live daemon runs a pinned binary and
was deliberately not restarted -- the store compaction workstream is in flight.
auto_term_empty_streak — the counter the 2026-08-06 review added to catch
exactly this — read 50 and climbing. Fifty consecutive curiosity scans where
the soul's dynamic seeding produced nothing and the loop fell back to four
hardcoded phrases. The live WM top said why in one look: every slot was a
Memory node labelled "memory:remembered". The extractor read the LABEL only,
the sentinel guard correctly rejects sentinels, so there was never anything
to extract. It was written against Knowledge nodes, which have real titles,
and was structurally blind to the node type that dominates working memory.
Rather than add a sixth guard to the five that accumulated across four
reviews (genre words, quoted titles, stopwords, label-df), invert the
algorithm. The old one was: take the first word, then check whether it is
acceptable. That shape forces quality to be expressed as rejection, and
rejection can only ever encode floods that already happened.
engram_salient_term() scores EVERY candidate token and returns the argmax of
idf · position · casing (YAKE, Campos et al. 2020, with real corpus IDF
substituted for YAKE's corpus-free proxies), falling back from a sentinel
label to the node's content. Term quality becomes the selection criterion
instead of a veto: a bad token loses to a better token in the same text
without needing to be on any list. Tabu is applied during the argmax, so
inhibition-of-return costs seed quality rather than costing the whole scan.
Two defects found by instrumenting rather than assuming, which is the lesson
this codebase keeps relearning:
- The first live run returned five ALL-CAPS terms in a row. Memory content
conventionally opens with an all-caps header, so YAKE's acronym bonus was
handing the seed to whatever word the heading started with. Restricted to
tokens <= 5 chars, where all-caps is evidence of an acronym rather than
evidence of a heading. Long headers now compete on specificity.
- df via istr_contains is substring matching, so "them" hit inside "theme"
and function words came back with nonzero df. Added word-boundary df
locally; engram_label_df keeps substring semantics for its callers.
An earlier draft claimed the min_df floor subsumed the 73 stopwords that
08-03 measured label-df as missing. Re-measured: about:2, whole:1, them:2 —
they clear a floor of 1. The claim was false and the comment now records the
correction. The floor buys lexical reachability; the argmax buys quality; the
stopword list still earns its keep.
Measured on 60 live Memory nodes before shipping: 0 empty, versus 60 of 60
under the old extractor. Terms are topical — HEBBIAN, CONSOLIDATION,
TEMPORAL, crash-loop, PRIMING, NEIGHBORHOOD, DRIFT. Three of sixty are weak
header words; left alone deliberately, because listing them is the move that
produced four blocklists.
ENGRAM_ST_DEBUG=1 dumps the scored candidate set. It exists because there was
no way to see whether the all-caps run was the corpus or the casing weight
without guessing.
Resolve 3 conflicts:
- lang/el-compiler/runtime/el_runtime.c: keep deletion (deprecated runtime fork;
single-source-of-truth is lang/runtime/, enforced by scripts/check-single-runtime.sh).
- lang/releases/v1.0.0-20260501/el_runtime.h: keep deletion (releases/ is a generated
artifact folder, not a source path; a release is a git tag, not a folder).
- lang/runtime/el_platform_win.h: union of dev's Windows port (#80: setsockopt optval
wrapper + curl-less libcurl stubs) and our fsync(->_commit) shim needed by engram_store WAL.
Nothing in dev's build consumes the deprecated fork or releases/ folder.
- Wire paged store into the ENGRAM SERVICE (server.el, the authoritative durable
owner): boot->engram_store_boot, persist_canonical->engram_store_checkpoint,
gated by ENGRAM_STORE.
- elc (lang/elc.c + src/parser.el + codegen.el + elc-combined.el): OOB guard in
tok_kind/tok_value + parse_block progress backstop — fixes the pre-existing
unbounded-memory fold hang on sessions.el.
- engram_prune_telemetry mirrors ISE prune to the store (store_forget) so store
live-count tracks resident and stale telemetry stays bounded.
- Deployed live 2026-08-12: engram :8742 on neuron.egm+WAL, count reconciled 11552.
Flag-on checkpoint now full-walks the resident graph: store_put_node (WM weight,
activation_count, last_activated, wm_anchor) + store_put_edge (hebb, last_fired)
for every node/edge, then engram_checkpoint. Uses store_put_edge (idempotent
upsert) not store_hebb_batch, because activation FORMS new hebbian-associate edges
that bypass the create hook and delta-only hebb_batch can't create them. Store-on
boot now applies the same WM-halving + floor + cap transforms as engram_load.
This is the hebb-survives-restart fix. Gate: reboot from neuron.egm with
snapshot.json deleted -> edge hebb + activation_count survive unchanged, WM weight
survives with identical boot transform; negative control proves persist is
load-bearing (hebb->0 without it). M1 33/33 + M2 36/36 + M3 parity PASS, ASan/UBSan
clean, flag-off untouched. Engine unchanged (boundary held).
Caller-side shim in el_runtime.c maps EngramNode/Edge <-> StoreNode/Edge; engine
keeps zero soul deps (libengram boundary, design §10). Flag off = today's JSON
path byte-for-byte (proven: no neuron.egm created, graph identical). Flag on =
engram_open (import snapshot.json once into neuron.egm, else WAL-replay) +
resident load; node/edge create + forget dual-write via guarded hooks. Files
renamed engram.store->neuron.egm, engram.wal->neuron.wal.
Gate: M3 parity PASS (graph on==off byte-exact modulo ordering; snapshot round-trip;
reboot-from-egm with snapshot.json deleted; activation set+sequence identical;
ASan/UBSan clean). M1 33/33 + M2 36/36 green post-rename.
Known gap (pre-flip): in-place hebb/WM/activation_count updates during activation
are not yet persisted to the store (create/connect/forget are). Must close before
live flip so learned edges survive restart.
Write-back no-steal buffer pool makes the fsync'd WAL load-bearing (M1 was
write-through). Logical WAL with record-granularity page-LSN redo idempotency.
Checkpoint = flush dirty pages, fsync store, advance last_checkpoint_lsn,
reclaim WAL prefix. One-time snapshot.json import only when store absent;
JSON never read as the ongoing store thereafter.
Gates: 33/33 M1 (no regression) + 36/36 M2 — replay parity, torn-tail fuzz
(every byte offset), checkpoint-crash at all 5 phases, torn-page+WAL redo,
legacy-import parity, hebb-survives-crash.
Establish lang/runtime/ as the ONE canonical el runtime (from the active
runtime that carries hebb/emb persistence + the new WAL); repoint the el CI
publish, engram build, elb default, and in-repo build scripts to it; delete
the el-compiler/runtime + lang/releases/ forks; add scripts/check-single-runtime.sh
drift guard.
Fixes a live prod bug: the el CI published el-runtime-c/-h from the LAGGING
el-compiler fork (0 hebb refs), so the shipped soul never persisted Hebbian
edge weights — learned co-activation was wiped on every restart. Publishing
from canonical ships the stranded 'learning that cannot outlive the process'
fix.
WAL storage engine + integrity fixes (DELETE->tombstone + store-layer
protection, safe data-dir default) ride in behind ENGRAM_WAL (default off =
byte-identical to today). Verified: engram elb per-module build clean, WAL
gate 66/66, native smoke ok, drift-guard green.
A cgi block is a top-level declaration, so codegen_streaming classifies it via
is_top_level_decl and releases it. The identity emission then searched
toplevel_exec_stmts for that same block. Declarations are excluded from that list by
construction, so the search could never succeed. A probe printed what it actually
saw for a program whose first statement is a cgi block: [Let, Expr]. It emitted
nothing, silently, with no diagnostic on any channel.
The code documented its own assumption — 'Since cgi blocks are rare and small, they
end up in toplevel_exec_stmts' — and that assumption was false.
Capture the declared values before the release and emit from them. The search is
deleted rather than repaired, so the failure mode is removed rather than relocated.
Proven discriminating (old fails, new passes):
minimal cgi program, old -> 0 el_cgi_init
minimal cgi program, fixed -> el_cgi_init with all four declared values
neuron soul, fixed -> principal present in the compiled binary (0 before),
boots in 2s, interface 110 routes in / 110 out
Consequence: a binary now carries its declared identity as a compiled constant,
which is what the identity protocol requires. Whether the runtime surfaces it to
state_get("soul_principal") is unverified and separate.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The loopback/API-key hardening carried in this file since 2026-07-15 called
el_http_request_authorized and el_http_send_401 from http_worker with no
forward declarations, so the calls were implicit and the later static
definitions conflicted. The file did not build. Two prototypes fix it.
Worth naming the pattern: uncommitted work is invisible to every check that
would have caught this. Three weeks of desktop security hardening was neither
committed nor compiling, and nothing reported either fact.
Same defect as the release runtime: \uXXXX was skipped and a literal '?'
emitted, destroying every non-ASCII character in JSON entering the runtime.
Two copies of one parser bug is how this class of fault survives a fix, so
it lands in both.
NOTE: this file also carries pre-existing uncommitted work from 2026-07-15/16
that this commit preserves rather than authors - loopback bind hardening
(EL_HTTP_BIND_HOST) and per-install API-key auth (EL_HTTP_AUTH_KEY) for the
shipped desktop build, plus goal-bias and node-json changes. It had been
sitting in the working tree for three weeks. Committing it because
uncommitted work is work that does not survive, which is the same durability
lesson as yesterday's Hebbian write-back finding. It needs review on its own
terms - see the backlog item for reconciling the two runtime copies.
jp_parse_string_raw handled \uXXXX by skipping the four hex digits and
emitting a literal '?'. JSON writers escape non-ASCII by default (Python's
json.dumps ships ensure_ascii=True; MCP clients do the same), so every em
dash, curly quote, accented letter and emoji arriving over MCP or HTTP was
silently replaced by one question mark on the way in.
Measured on the live store: 3,119 of 4,081 non-telemetry nodes carried the
damage, including the self traversal root and all 13 values nodes. Contents
split cleanly into fully-clean or fully-mangled with zero overlap, which is
the tell that it was one write path rather than gradual rot. No snapshot on
disk predates it, and 3 bytes collapsing to 1 is not invertible, so the
existing damage is permanent; only the forward path could be fixed.
Decode properly instead: 4 hex digits, surrogate-pair reassembly for astral
codepoints, U+FFFD for lone surrogates, UTF-8 encode. Malformed escapes keep
the old '?' so a truncated body still parses.
The deeper failure was that nothing measured this for two months. Every gauge
in the system reports whether the machinery is running; none reported whether
the text it carries is intact. Adds both halves: engram_text_health_json() /
GET /api/text-health for the daily census, and a txt_damaged counter on the
heartbeat for live regression. Verified in both directions - clean UTF-8 does
not trip it, a deliberately damaged node does.
Yesterday's eligibility-trace fix made Hebbian consolidation numerically real:
hebb_max 0.000799 -> 0.4725, and 1,198 hebbian-associate edges formed in 23h48m.
This morning's census found where they went: nowhere.
soul daemon (in-process graph): 42,426 edges, 1,198 hebbian
engram server (:8742, durable): 41,213 edges, 49 hebbian
Two processes, two graphs, one direction of travel. The soul pulls from the
server every 10 min (GET /api/sync) and never pushes. It cannot fall back on
saving its own copy either: soul.el sets soul_snapshot_path only inside
`if is_genesis && safe_to_seed`, and safe_to_seed is unconditionally false
whenever ENGRAM_URL is set -- because the server owns persistence and a soul
writing snapshot.json would clobber it. That guard is correct. The consequence
was not: mem_save() has never once executed. The soul is the ONLY process
running idle cognition, so it is where essentially all co-activation happens --
and it was throwing away every association it learned, every restart, silently.
The mechanism worked and the learning still evaporated.
Consolidation is now a message, not a file. Fast volatile store hands each
newly-formed association to the slow durable store over the API the server
already exposes; only edges past ENGRAM_HEBB_LINK_MIN are ever queued, so what
crosses the process boundary already earned it.
- el_runtime.c: 512-slot overwrite-oldest write-back ring; enqueue at edge
formation; engram_hebb_drain_json() pops a postable JSON batch. Drops and
drains are counted, not silent -- a consolidation path that quietly discards
is the exact failure this entry exists to correct.
- server.el: POST /api/edges/batch. persist_canonical() writes the full 60MB
snapshot per call, and route_create_edge calls it per edge -- correct for one
interactive edge, ruinous for bulk (~840MB/beat to persist 14 associations).
Batch connects all, snapshots once. Same durability, 1/N the writes.
- act-stats: hebb_wb_pending / _drained / _dropped. pending climbing with
drained flat = drain not called; drained climbing with sent 0 = POST refused.
Both failure modes are now visible in the stream instead of in an autopsy.
Verified live: batch route accepts valid entries, skips malformed ones without
aborting the batch, and enforces _auth. All 1,256 learned associations are now
in the canonical store; the soul booted at 42,431 edges with hebb_max 0.4941
carried across the restart for the first time.
Hebbian consolidation was inert. Census over the live graph (41,213 edges,
13,091 nodes, 23h44m uptime): strongest association hebb=0.000799 against a
0.15 consolidation threshold, and zero hebbian-associate edges ever formed.
Since the awareness loop calls engram_connect nowhere, this was the only path
by which the graph could grow its own structure — every edge was authored or
imported, none learned.
The defect was the event, not the rate. hebb is an EWMA whose fixed point is
P(event); raising ETA changes convergence speed, never the plateau. The event
was "both endpoints in WM in the same activate call" — demanded exact
simultaneity from a working memory that inhibition-of-return, breakthrough
rotation and the 24-slot global cap are all engineered to keep turning over
(~142 evictions/60s). The three mechanisms that make WM healthy are the ones
that made this measurement empty.
Replaced with three-factor eligibility traces (Sutton & Barto ch.7; Gerstner
et al. 2018; PLOS Comp Biol 2018 differential Hebbian learning): a node
entering WM sets a trace to 1.0, the trace decays exponentially in wall-clock
time (TC=300s, chosen against the measured ~31s scan cadence), and the
increment becomes ETA·trace(a)·trace(b). Strict generalization — co-resident
pairs read 1.0 on both ends and get exactly ETA, bit-identical to before.
warm×warm is deliberately not paired: eligibility must gate on something
happening now. Homeostatic ENGRAM_HEBB_NODE_BUDGET still bounds per-node mass.
Measured over a 60-call soak: hebb_max 0.0008 -> 0.0060, climbing at ~0.87
ETA/call against an all-time ceiling of 0.0008 before. hebb_mass 0.011 ->
0.019, no runaway. Projected consolidation of a genuinely recurring pair:
~1,730 calls, ~14h at autonomous cadence. links still 0 — that is expected
and is what tomorrow's review must check.
Also: Pass 3½ deduplicates this call's WM candidates, but the persisted WM
population is a union of fresh promotions and carry-over residents, and Pass
3½ never sees the second set. Confirmed live: two byte-identical copies of one
3,193-char document both holding slots (0.289 / 0.271). Added global
redundancy suppression in Pass 5 before the cap count. Post-fix census: 24
residents, 24 distinct contents, 0 wasted slots.
New gauges: hebb_warm (eligible-but-not-co-resident population), dup_wm_global.
Census of the live graph under the uniform 168h half-life with floor 0.05: the
MEDIAN tdecay for every single node type was 0.0500 — the clamp. Memory 81% at
floor, Knowledge 58%, BacklogItem 91%, Project 98%, Tag 100%. A function whose
median output is its floor is not a signal, it is a constant with exceptions,
and the exceptions were whatever had been touched in the last few days.
What that cost: 10 of the 13 grounded value nodes — Precision Over Brute Force,
Honesty Before Comfort, The System Must Accumulate — sat at 0.05, a 20x
activation penalty, while Knowledge ingested overnight sat near 1.0 and held the
working-memory top slots. Since tdecay multiplies at every hop, a 2-hop path
through settled knowledge compounded to 0.0025: those regions were not
disfavoured, they were unreachable. The decay function was erasing the
accumulated library in favour of whatever arrived last night.
External corroboration — arXiv:2604.26970 measures retrieval under decay
regimes: no temporal weighting NDCG@5 0.274, uniform exponential decay 0.015.
Uniform decay is 18x WORSE than no decay, because it penalises stable knowledge
while failing to suppress stale volatile facts. Not even their full adaptive
hierarchy (0.260) beat switching decay off.
Half-life is now scaled by how established a node is:
T_eff = T_HALF * (1 + ln(1 + activation_count))
The spacing effect and the Lindy property in one line — monotone, log-bounded
(a 10,000-activation node earns ~10x, never a permanent exemption), and built
on activation_count, which is measured, unlike tier, whose assignments are too
inconsistent to trust (the values node is tagged Episodic).
Floor 0.05 -> 0.25. Given no-decay outperforms uniform decay, the honest maximum
penalty for age alone is 4x, not 20x. Age should express a preference for the
recent; it must never make a region of the graph structurally unreachable.
Effect: well-established Knowledge median tdecay 0.773 vs rarely-activated
0.417 — the frequency signal now does work where the old function returned its
clamp for both. Values recover 0.05 -> 0.25 (the two frequently-touched ones to
0.79). Verified live: VBD whitepaper, component taxonomy and CGI now activate on
a values query. Per-node temporal_decay_rate override untouched.
Content-hash census of the live graph: 1,858 redundant copies, 44.9% of the
non-ISE store, all from a June id-scheme migration that re-added nodes under
fresh UUIDs instead of matching on content. Generation stopped in June; the
copies did not. Being byte-identical they carry identical embeddings, so they
score identically against any query.
Measured over 50 real query probes against the live 3,998-vector set:
40.2% of semantic seed slots were consumed by redundant copies of content
already in the seed set, 92% of retrievals affected, effective distinct seeds
4.78 of 8. Two fifths of every retrieval was spent re-reading the same page.
Deleting nodes is a separate operation with its own backup discipline. This
change makes the runtime immune to the condition instead: redundancy can never
buy a scarce slot, whatever state the graph is in. Enforced at both scarcity
points — semantic seed selection (a rejected copy does not consume one of the K
slots; the loop retries for the next distinct node) and WM admission via a new
Pass 3+1/2 ahead of the capacity cap, so 24 slots are contested by 24 distinct
meanings rather than by however many copies of one document exist.
Identity is exact content hash first, then cosine >= 0.995 for copies that
differ only in insignificant characters. At 768 dimensions that admits only
near-verbatim text: this suppresses redundancy, never similarity.
Live after restart: ~8.8 redundant seed candidates rejected per activation.
New dup_seeds/dup_wm gauges in act-stats.
WM continuity (the significant one). A node reached by the current query but
scoring under its type threshold was zeroed outright, while a node the query
did NOT reach got the full ACT-R carry-over treatment. Being found was punished
relative to not being found. Measured consequence: WM turned over 100% every
call — three activations of a byte-identical query gave |A∩B| = |B∩C| = 0 — and
wm_evicted stayed 0 the whole time because that path never counted. WM was not
a working set; it was six suppression-breakthrough nodes re-drawn per call.
Both exits from a WM slot now share one extracted retention rule.
Result: WM 6 -> 24 nodes (the designed Cowan capacity), top weight 0.097 ->
0.748 (natural promotion, not the breakthrough floor), and contents that are
actually query-relevant.
Hebbian learning. Edge weights were written once at engram_connect and never
changed; last_fired's only writer in 12.5k lines was an unrelated dharma path.
Every learning mechanism operated on nodes — the wiring between them was
frozen. Adds co-activation potentiation (HeLa-Mem arXiv:2604.16839) in a
separate `hebb` field so authored structure is never mutated, with homeostatic
per-node scaling the source lacks (PNAS 2422602122) to prevent hub saturation.
Measuring it produced the finding that mattered: zero edges existed between
co-active WM members, so reweighting existing edges was a no-op. This graph's
41k edges were all authored by explicit tool calls — nothing had ever formed an
association from experience. So Hebb literally: if the wire is absent, grow it.
Consolidation is gated hard (sustained EWMA past 0.15, <=2/call, 5% ceiling,
in-memory candidates discarded on restart) because it permanently mutates the
graph.
Two bugs caught only by instrumenting rather than assuming: the snap-to-zero
floor sat above the per-step increment, so nothing could ever accumulate; and
the reached-but-sub-threshold eviction above. Verified live end to end — 53
links formed under load, then discarded with the test snapshot.
Also exposes engram_act_stats_json over GET /api/act-stats. It had existed
since 2026-07-27 but was reachable only through the soul daemon, so diagnosing
the activation layer required a working soul. This review needed it and could
not get at it.
The soul's curiosity auto-term extractor takes the first word of a top-WM
node label. It has no term-quality scoring, so three prior self-reviews each
bolted on another hand-curated blocklist (genre words 07-23, quoted titles
07-25, stopwords 07-30). Every one was written reactively, after a flood was
already observed. A list can only contain floods that already happened.
Two were in flight and unfixed when this review ran:
"<!--" label df 220 -> 252 nodes activated
"SELF" label df 175 -> 541 nodes activated (list has "Self" Title-case;
str_eq is case-sensitive, so the uppercase token sailed through)
engram_label_df(term) counts nodes whose label contains term. Low-specificity
tokens are corpus-frequent by definition, so this catches the flood class
prospectively and tracks the corpus as the world-ingestor changes it. This is
Sparck Jones (1972), which introduced IDF under the name 'term specificity';
automatic stopword compilation from it is the textbook application.
NOT a replacement for the stopword list -- verified against all 86 listed
terms, not assumed. Catches 13 (Will:306, Self:175, Over:116, Knowledge:112),
misses 73 (Whose:0, Would:0, Could:0, This:9). Labels are terse titles, so
English function words are genuinely rare in them. The gates cover disjoint
failure modes; both are required.
Policy lives in awareness.el, not here: the runtime measures, the soul decides.
Working memory was thrashing behind a healthy-looking gauge. wm_active sat
at 22-24 while breakthroughs ran 661-903 and evictions 485-717 PER 60s tick
- roughly 825-1125 nodes cycling in 5-call lockstep.
Root cause: the breakthrough path was an anti-starvation mechanism that reset
its own counter on firing, with no budget and no refractory. A node failing
its type threshold 5 times was force-promoted at exactly 0.10 and had its
suppression_count reset to 0, so it immediately restarted the identical
climb. Since BREAKTHROUGH_WEIGHT (0.10) > WM_FLOOR (0.05), every one of them
cleared the admission floor and entered the rank contest tied at 0.10, where
the tie-break degenerated to node-array index order. Cap-evicted nodes are
skipped by retrieval reinforcement, so they never got an access_ts record and
the STI inhibition-of-return damper never applied to them. That closed the
loop: re-suppressed, completely unmarked, forever.
An anti-starvation rule that resets its own counter without a bound is not a
fairness valve, it is an oscillator.
Fixes in engram_activate Pass 2:
- ENGRAM_BREAKTHROUGH_BUDGET (WM_CAP/4 = 6) caps intrusive thoughts per call.
- ENGRAM_BREAKTHROUGH_COOLDOWN (55) via NEGATIVE suppression_count. The field
already serializes as %d and parses through eg_get_int_field, so negatives
round-trip through snapshots with no struct or format change.
- Blocked breakthroughs no longer reset the counter; it saturates so a starved
node surfaces on a later call instead of restarting from zero.
- Graded breakthrough weight by nearness to own threshold, so the rank
tie-break is cognitive rather than insertion order. Invariant preserved:
WM_FLOOR < weight < min(type_threshold).
Also: moved the additive cosine term AFTER the STI multiplier. It was applied
before, so an incumbent re-reached 30s later took t_n/(t_n+120) = 0.2x, which
cut the semantic term's ceiling from 0.20 to 0.04 - below every per-type
threshold. Meaning-match was being punished for having been recently useful.
Inhibition-of-return should rotate the structural score, not the semantic one.
Also: _eg_act_wm_evicted counted 3 of 5 eviction paths. The two carry-over
paths were silent, so the reported rate was an undercount of unknown
magnitude - while being used to diagnose an eviction pathology. All five now
increment.
Also: route_sync returned {"nodes":[],"edges":[]} when the snapshot export
failed. The soul's sync_ok check only tests for "" and "{}", so that
placeholder passed as a healthy sync: last_sync_ok_ts stamped, sync_age_ms
green, sync_empty never fired, added:0 forever. A broken sync was
indistinguishable from a quiet healthy one - the exact class this route was
added to fix. Returns a real error now.
Verified live (boot 20 vs boot 19): breakthroughs 661-903 -> 36/tick,
evictions 485-717 -> 12-46/tick against a counter that now covers more paths,
wm_active unchanged at 22-24, wm_avg_weight 0.138-0.273 -> 0.186-0.446.
Working memory is holding strong nodes instead of breakthrough-floor filler.
Every node object on consumer read routes (/api/nodes, /api/search,
activation results, neighbors, compiled context) carried the full ~5.7KB
emb vector — responses 10-50x oversized, blowing MCP token limits.
engram_emit_node_json now takes include_emb; only engram_save passes 1,
so persistence and the /api/sync//api/edges replication paths (which
serve engram_save output) keep embeddings intact.
_eg_act_wm_evicted/_eg_act_breakthroughs were reset at the top of every
engram_activate, so act_stats reported only the last call and the 60s
heartbeat missed nearly all events (curiosity runs 2 activates per 30s).
Both are now monotonic process-lifetime totals; consumers diff readings.
Working memory was pinned saturated (24/24, wm_saturated:1 on every
heartbeat) because every cap path only trimmed the population down TO
the cap — rank-based eviction guarantees a full WM whenever >=24 nodes
hold any weight, so sub-cap fill was unreachable and the saturation
flag carried no information.
- ENGRAM_WM_FLOOR 0.05: absolute admission bar (Soar WM forgetting,
Derbinsky & Laird ICCM 2012 — removal by absolute threshold, not
rank) applied in Pass 4, carry-over, Pass 5, and load-cap. Fill can
now drain below 24 during quiet periods.
- Zero wm_anchor at every eviction site: stale anchors on evicted
nodes were a latent resurrection bug.
- Context centroid folds only NEW WM entrants: incumbents re-promoted
every scan no longer re-entrench the centroid each call, breaking
the WM->centroid->e_eff->re-selection positive feedback (fixation
driver behind the wm_top0_streak=1407 incident).
Verified live: wm_active 3->22->23, wm_saturated:0 post-restart.
n->importance was stored, serialized, and clamped at creation but never
read by any activation path — a curated importance=1.0 node competed
identically with a default note. Multiply raw_wm by (0.5 + importance):
default 0.5 nodes are unchanged (x1.0), critical x1.5, low x0.6;
importance<=0 from legacy snapshots stays neutral. Verified activation
and WM promotion unchanged for default-importance candidates.
- Gate each spreading-activation increment by target-node query similarity
(arXiv:2606.30133): soft gate FLOOR+(1-FLOOR)*clip(cos), FLOOR=0.25, for
embedded targets; ungated for unembedded; disabled when embedder is down.
Prior spreading was query-blind — hubs relayed activation into branches
unrelated to the query.
- Stats: add embed_eligible_count so embedding coverage is measured against
the true denominator (ISE/Tag/short nodes can never embed). Today's review
misread 3753/12693 as a 30% coverage gap; eligible coverage is 100%.
- Observability: per-call wm_evicted + breakthroughs counters and embed
circuit-breaker state exposed via engram_act_stats_json() — the three
highest-value previously-invisible executive-filter transitions.
- Carry-over branch: occupancy inhibition m = t_c/(t_c+t_hold), t_c=3600s
(ENGRAM_CARRY_TC). An unreached incumbent held its wm_anchor verbatim
(keep~1.0 for BLL inflated in the pre-07-25 era) — observed 23h at WM
top while every reached node rotated at the 0.10 breakthrough floor.
STI only runs in the reached branch; inhibition must key on occupancy,
not retrieval recency (Morita 2021 / Lebiere & Best 2009).
- engram_strengthen: drop the 07-22 BLL access record — the 07-25 STI
multiplier reads the same ring, so novelty reinforcement self-inhibited
its target for ~2 minutes.
- engram_load reset: free n->emb (~3KB/embedded node leaked per reload).
- engram_wm_top_json: emit id — its absence made the heartbeat's
wm_top0_streak compare ""=="" and measure uptime, not fixation.
Working memory was winner-take-all: suppression_count never entered the
promotion score and was reset on promotion, so two high-salience nodes
pinned a saturated 24-slot WM for hours. Add Lebiere-Best (CogSci 2009)
short-term inhibition — raw_wm *= t_n/(t_n + 120s) from the most recent
recorded access — producing emergent round-robin over WM candidates.
embedded_count stalled at 93/12175 after restart: the lazy backfill only
runs inside engram_activate, which nothing calls on the authoritative
store in production, and in-RAM vectors were never snapshotted. Add
engram_embed_backfill(n) + GET/POST /api/embed-backfill route that
persists the canonical snapshot whenever it embeds anything; the soul
heartbeat pumps it at 32/min.
Semantic activation was spec-only since 2026-06-30 — the seed loop used
istr_contains and nothing else. Per the 07-21 integration brief:
- EngramNode gains a lazily-backfilled nomic-embed-text vector (8/call
inside engram_activate, newest-first; no create-path latency, no bulk
Ollama hammering during sync seeds)
- query embedding (cached) drives a top-K cosine seed supplement
(HippoRAG use-similarity-twice) plus an additive WM term with
shift-and-floor at 0.45 — raw cosine is a constant bias in anisotropic
spaces (unrelated pairs read 0.4-0.7), floor-and-ramp makes it a signal
- 4s embed timeout (http_do_t) + 3-strike circuit breaker: activation
never wedges on a dead embedder; everything degrades to lexical
- embeddings persist as %.4g comma lists in snapshots, parsed by both
loaders; embedded_count in /api/stats tracks coverage
- engram_cosine_sim + http_delete_json exposed (DELETE now carries a
body — the server's _auth scheme requires it)
- route_create_node honored only content/node_type/salience; label,
importance, tier, tags were silently dropped (label defaulted to
content). Now honored via engram_node_full.
Verified live: embedded_count 0->96 across activations, semantic-only
promotion observed (zero token overlap), snapshot round-trip intact.
The desktop soul (neuron/dist) compiles against the v1.0.0-20260501 release
runtime. After #66 landed the engram natives (tokenized/ranked search,
engram_prune_telemetry) and #79 the durable truncation fix into this runtime,
two gaps remained before it could cross-compile the Windows brain:
1. Windows OS boundary: the release runtime had no Win32 path. Ported the same
_WIN32-guarded shim the mainline runtime carries (#69): #ifdef _WIN32 ->
el_platform_win.h (winsock/dlsym/popen + WSAStartup ctor), SOCKET fd guards
and el_closesocket() at every socket site, CreateProcessA for exec_bg, the
tm_zone/mingw guard, an el_setsockopt optval wrapper (GCC14), and curl-less
libcurl stubs. Every change is _WIN32/HAVE_CURL-gated — the POSIX build is
byte-identical (gcc -fsyntax-only clean; native behaviour unchanged).
2. Header exports: the release el_runtime.h omitted symbols the soul dist calls
that are defined in this runtime's .c — the http_handler_fn/http_handler4_fn
typedefs and el_arena_push/pop, engram_prune_telemetry, engram_get_node_by_label.
Declaration-only, POSIX-neutral; fixes implicit-declaration/unknown-type
errors under the C11 mingw build.
Result: x86_64-w64-mingw32-gcc compiles el_runtime.c + all 48 soul modules
clean; POSIX gcc -fsyntax-only clean. This is the Windows-port PR the runtime
needed on main (the release-runtime counterpart to #69), landed via stage.
The binary-safe fs_read length (_tl_fs_read_len) was consumed by the HTTP
response path for ANY body, even when a handler wrapped a smaller file into a
larger reply. Content-Length then lied AND the send stopped short: the
safety-contact (988) routes returned 178 of 208/218 bytes, cut mid-'set_at' —
unparseable JSON. The desktop app read that as failure. On Windows the shipped
brain is an OLD build without even the per-handler workaround, so EVERY reply
truncated: the app can't read confirmations and refuses the new user.
Durable fix: pair the length hint with the exact buffer pointer it describes
(_tl_fs_read_buf). Apply the raw byte count ONLY when the response IS that
buffer (binary file serving stays correct); every wrapped/enveloped/derived
body is measured with strlen. Reset both at request start and in fs_read /
json_get_raw. This also closes the stale-hint heap over-read (a length larger
than a later body would read past it out the socket) that a plain max() leaves
open — so this class of bug dies on every platform, not just where a handler
happened to be patched.
Applied identically to the mainline runtime (lang/el-compiler/runtime) AND the
frozen release runtime (lang/releases/v1.0.0-20260501) the desktop souls
compile against — the release copy still carried the raw leak, which is why the
Windows brain kept truncating. Same proven approach as PR #78 (Tim Lingo),
extended to cover the release runtime and rebased onto current main.
Both runtimes: gcc -fsyntax-only clean.
Durability: the 2026-07-21 fix stopped read routes writing the canonical
snapshot but left no save on ANY write path — every mutation lived in RAM
until a manual POST /api/save. Observed live: two restarts reverted the
store to a 17h-old snapshot, destroying same-day writes. persist_canonical()
now runs after node/edge create, knowledge capture, forget, strengthen, and
load-merge. ISE telemetry excluded deliberately (48h-pruned, loss-tolerant,
~2/min; snapshotting 28MB per heartbeat is waste).
Listing order: scan routes sort by salience with store-order ties, so
equal-salience telemetry (all ISEs are 0.3) returned OLDEST first — a
limited /api/nodes query silently returned a stale window, and a 41h-old
heartbeat series read as a live outage during this review. Ties now break
newest-first by created_at.
The old carry-over (weight *= 0.7 per engram_activate call) was call-rate-
dependent — carried context died in seconds under rapid curiosity scans and
lingered for hours under quiet loops — and a decayed scalar cannot represent
access frequency at all.
Now: k=10 access-timestamp ring + Petrov (2006) closed-form tail, d=0.5.
WM promotion and engram_strengthen record presentations; carry-over evicts
at base-level tau=-3.0 (Soar forgetting, ~403s single-touch) and shapes the
weight held at promotion (wm_anchor) with the ACT-R retrieval logistic
(s=0.4) — a pure function of wall-clock time, idempotent per call.
Persisted as access_ts/wm_anchor in snapshots; legacy nodes fall back to
the optimized form ln(n/(1-d)) - d*ln(L). base_level exposed in both node
serializers for observability.
Backing spec: 2026-07-21 integration brief (bl-b17facdd). Verified live:
carried weight ~anchor seconds after two disjoint activations (old code:
0.49x); frequency-hot nodes hold B=1.9 vs -0.14 single-touch.
Three fixes that existed elsewhere but never reached the runtime the engram
binary actually builds against:
- tokenized + ranked query matching (search/search_json/activate seeds/
goal_bias) ported from the el-compiler copy (e3dabe3, 2026-07-14) — the
production engram kept whole-query Ctrl-F for 5 days after the fix
'shipped'. Multi-word curiosity seeds went 0 -> 36 activated. Kept the
ISE seed exclusion the el-compiler copy dropped.
- Knowledge -> 0.20 WM threshold after tier checks (dev-line 4bf7716):
Semantic/Episodic Knowledge nodes fell to the 0.40 note default and only
entered WM via breakthrough.
- goal_bias: Knowledge in is_knowledge + curiosity-seed technical terms
(dev-line d53516b).
Also: seed_epoch was a running pairwise average, not the mean it claimed —
exponentially over-weighted later seeds in the temporal-proximity bonus.
Fixed to a true int64-sum mean. Stale INHIBITION_FACTOR comment corrected.
Root cause captured as knowledge: two runtime copies + branch-per-fix
without merge discipline stranded the entire dev semantic layer (cosine
activation, embeddings) out of production. Reconciliation planned as P1.
1. engram_neighbors_json (release runtime): BFS frontier/visited strings were
el_strdup'd (arena-tracked) but manually freed, so el_request_end()
double-freed every one — SIGABRT in http_worker under load (2 prod crashes
today via /api/neuron/session/begin and /api/neuron/graph; reproduced and
verified fixed with ASAN). Introduced when porting from the dev runtime,
which correctly uses plain strdup. Third instance of the
arena-vs-manual-free class (after EngramNode 07-15 and idmap keys 07-16).
2. server.el: let-in-if scoping sweep — defaults assigned inside if-blocks
never mutated the outer binding, so /api/search and /api/activate always
ran with q="", created nodes got node_type=""/salience=0.0, edges got
relation=""/weight=0.0, and save/load with no path hit engram_save("").
Rewritten to the let-if-else expression form. /api/activate now also
rejects empty queries instead of wiping carried WM weights.
3. engram_activate: retrieval reinforcement (ACT-R base-level learning) —
nodes promoted to WM that survive both capacity caps now get
last_activated/activation_count updated, so frequently retrieved memories
decay slower than abandoned ones. Scoped to promoted-only to avoid
flattening dampening across BFS fan-out.
bigmerge
will.anderson