fix(facts): seed phase B backfill row_nums past the DB max (#2044 class)

phaseBFenceFacts appended at fence-max+1 with no DB seeding, so on a
diverged page (stamped DB rows + missing fence at the resolved path —
the same divergence class the writeFactsToFence fix handles) the
post-rename UPDATE hit idx_facts_fence_key, the page failed, and the
already-renamed fence disagreed with the DB while the row_num-NULL
backlog persisted. Seed appended row_nums from MAX(fence max, DB max)
per (source_id, slug), mirroring the fence-write fix. Repro test added.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/cli.ts

@@ -54,7 +54,7 @@ export function bigintToStringReplacer(_key: string, value: unknown): unknown {
 }
 
 // CLI-only commands that bypass the operation layer
-export const CLI_ONLY = new Set(['init', 'reinit-pglite', 'upgrade', 'post-upgrade', 'check-update', 'integrations', 'publish', 'check-backlinks', 'lint', 'report', 'import', 'export', 'files', 'embed', 'serve', 'call', 'config', 'doctor', 'migrate', 'eval', 'sync', 'extract', 'extract-conversation-facts', 'enrich', 'features', 'autopilot', 'graph-query', 'jobs', 'agent', 'apply-migrations', 'skillpack-check', 'skillpack', 'resolvers', 'integrity', 'repair-jsonb', 'orphans', 'sources', 'mounts', 'dream', 'check-resolvable', 'routing-eval', 'skillify', 'smoke-test', 'providers', 'storage', 'repos', 'code-def', 'code-refs', 'reindex', 'reindex-code', 'reindex-frontmatter', 'code-callers', 'code-callees', 'reconcile-links', 'frontmatter', 'auth', 'friction', 'claw-test', 'book-mirror', 'takes', 'think', 'salience', 'anomalies', 'calibration', 'transcripts', 'models', 'remote', 'recall', 'forget', 'edges-backfill', 'cache', 'ze-switch', 'founder', 'brainstorm', 'lsd', 'schema', 'capture', 'onboard', 'conversation-parser', 'status', 'connect', 'skillopt', 'quarantine', 'self-upgrade', 'advisor', 'watch', 'reindex-search-vector']);
+export const CLI_ONLY = new Set(['init', 'reinit-pglite', 'upgrade', 'post-upgrade', 'check-update', 'integrations', 'publish', 'check-backlinks', 'lint', 'report', 'import', 'export', 'files', 'embed', 'serve', 'call', 'config', 'doctor', 'migrate', 'eval', 'sync', 'extract', 'extract-conversation-facts', 'enrich', 'features', 'autopilot', 'graph-query', 'jobs', 'agent', 'apply-migrations', 'skillpack-check', 'skillpack', 'resolvers', 'integrity', 'repair-jsonb', 'orphans', 'sources', 'mounts', 'dream', 'check-resolvable', 'routing-eval', 'skillify', 'smoke-test', 'providers', 'storage', 'repos', 'code-def', 'code-refs', 'reindex', 'reindex-code', 'reindex-frontmatter', 'code-callers', 'code-callees', 'reconcile-links', 'frontmatter', 'auth', 'friction', 'claw-test', 'book-mirror', 'takes', 'think', 'salience', 'anomalies', 'calibration', 'transcripts', 'models', 'remote', 'recall', 'forget', 'edges-backfill', 'facts', 'cache', 'ze-switch', 'founder', 'brainstorm', 'lsd', 'schema', 'capture', 'onboard', 'conversation-parser', 'status', 'connect', 'skillopt', 'quarantine', 'self-upgrade', 'advisor', 'watch', 'reindex-search-vector']);
 // CLI-only commands whose handlers print their own --help text. These are
 // excluded from the generic short-circuit so detailed per-command and
 // per-subcommand usage stays reachable.
@@ -991,6 +991,8 @@ const THIN_CLIENT_REFUSED_COMMANDS = new Set([
   // hint pointing at the routable MCP tools; per-subcommand splits are
   // a v0.31.x follow-up TODO.
   'takes', 'sources',
+  // #1867: fence-backfill edits local .md fences + stamps the local DB.
+  'facts',
   // v0.32 thin-client routing audit (Codex round 2 findings #2, #4):
   // - `pages` purge-deleted is admin+localOnly (operations.ts:856-864)
   // - `files` list / file_url MCP ops are localOnly (operations.ts:1769-1879)
@@ -1026,6 +1028,7 @@ const THIN_CLIENT_REFUSE_HINTS: Record<string, string> = {
   migrate: "migrate runs on the host's local engine. Run on the host machine.",
   'apply-migrations': 'schema migrations run on the host. SSH and run there.',
   'repair-jsonb': 'repair-jsonb operates on the local DB only.',
+  facts: 'facts fence-backfill edits local entity-page fences. Run on the host machine.',
   integrity: 'integrity scans local files. Run on the host machine.',
   serve: 'serve starts a server. Run on the host, not the thin client.',
   dream: 'dream runs the autopilot cycle on the host. `gbrain remote ping` queues one. (Native `gbrain dream` thin-client routing planned for v0.31.2.)',
@@ -1855,6 +1858,13 @@ async function handleCliOnly(command: string, args: string[]) {
         await runEdgesBackfill(engine, args);
         break;
       }
+      case 'facts': {
+        // #1867 — re-runnable fence-backfill for row_num-NULL legacy fact
+        // rows (idempotent v0_32_2 phase B, exposed as an operator command).
+        const { runFactsCommand } = await import('./commands/facts.ts');
+        await runFactsCommand(engine, args);
+        break;
+      }
       case 'whoknows': {
         // v0.33 (Issue #?): expertise + relationship-proximity routing.
         // MCP op `find_experts` (read-scoped) backs the same code path; CLI
@@ -2335,6 +2345,7 @@ TOOLS
   check-backlinks <check|fix> [dir]  Find/fix missing back-links across brain
   lint <dir|file> [--fix]            Catch LLM artifacts, placeholder dates, bad frontmatter
   orphans [--json] [--count]         Find pages with no inbound wikilinks
+  facts fence-backfill [--dry-run]   Fence legacy fact rows (row_num NULL) onto entity pages
   salience [--days N] [--kind P]     v0.29: pages ranked by emotional + activity salience
   anomalies [--since D] [--sigma N]  v0.29: cohort-based statistical anomalies (tag, type)
   transcripts recent [--days N]      v0.29: recent raw .txt transcripts (local-only)

src/commands/facts.ts

@@ -0,0 +1,48 @@
+/**
+ * gbrain facts — fact-store maintenance surface (#1867).
+ *
+ * `fence-backfill` re-runs the v0_32_2 fence-backfill phase on demand.
+ * Remote `extract_facts` deposits that predate the fence-write backstop
+ * (and any legacy DB-only insert) leave `row_num IS NULL` rows that the
+ * cycle extract_facts guard refuses to reconcile past — previously the
+ * only remedy was the one-shot v0_32_2 migration, which the ledger marks
+ * complete and never re-runs. The phase is idempotent (only touches
+ * `row_num IS NULL` rows), so exposing it as a command is safe to re-run
+ * any time the backlog reappears.
+ */
+import type { BrainEngine } from '../core/engine.ts';
+import { setCliExitVerdict } from '../core/cli-force-exit.ts';
+import { phaseBFenceFacts } from './migrations/v0_32_2.ts';
+
+function printHelp(): void {
+  process.stderr.write(
+    `Usage: gbrain facts fence-backfill [--dry-run]\n\n` +
+      `Fence-backfill: appends every legacy fact row (row_num IS NULL) to its\n` +
+      `entity page's \`## Facts\` fence and stamps row_num + source_markdown_slug\n` +
+      `back onto the DB row. Idempotent — re-runs only pick up rows still\n` +
+      `missing a fence assignment. Clears the backlog that makes the cycle's\n` +
+      `extract_facts phase skip fence→DB reconciliation.\n\n` +
+      `  --dry-run   report what would be fenced; no FS or DB writes\n`,
+  );
+}
+
+export async function runFactsCommand(engine: BrainEngine, args: string[]): Promise<void> {
+  const sub = args[0];
+  if (!sub || sub === '--help' || sub === '-h') {
+    printHelp();
+    return;
+  }
+  if (sub !== 'fence-backfill') {
+    process.stderr.write(`Unknown facts subcommand: ${sub}\n`);
+    printHelp();
+    setCliExitVerdict(1);
+    return;
+  }
+
+  const dryRun = args.includes('--dry-run');
+  const result = await phaseBFenceFacts(engine, { dryRun });
+  process.stderr.write(
+    `fence-backfill: ${result.status}${result.detail ? ` — ${result.detail}` : ''}\n`,
+  );
+  if (result.status === 'failed') setCliExitVerdict(1);
+}

src/commands/migrations/v0_32_2.ts

@@ -39,6 +39,7 @@ import type { BrainEngine } from '../../core/engine.ts';
 import { loadConfig, toEngineConfig } from '../../core/config.ts';
 import { createEngine } from '../../core/engine-factory.ts';
 import { upsertFactRow, parseFactsFence } from '../../core/facts-fence.ts';
+import { resolvePageFilePath } from '../../core/markdown.ts';
 
 let testEngineOverride: BrainEngine | null = null;
 export function __setTestEngineOverride(engine: BrainEngine | null): void {
@@ -148,9 +149,16 @@ function isLocalPathDirty(localPath: string): boolean {
   }
 }
 
-async function phaseBFenceFacts(
+/**
+ * Exported (not just via `__testing`) because `gbrain facts fence-backfill`
+ * (#1867) re-runs this phase on demand: remote `extract_facts` deposits that
+ * predate the fence-write backstop leave row_num-NULL rows the cycle guard
+ * refuses to reconcile past. The phase is idempotent (only touches
+ * `row_num IS NULL` rows), so re-running is always safe.
+ */
+export async function phaseBFenceFacts(
   engine: BrainEngine | null,
-  opts: OrchestratorOpts,
+  opts: Pick<OrchestratorOpts, 'dryRun'>,
 ): Promise<OrchestratorPhaseResult> {
   if (opts.dryRun) {
     // Dry-run: report what WOULD happen without touching FS or DB.
@@ -238,7 +246,11 @@ async function phaseBFenceFacts(
     for (const [key, group] of groups) {
       const [sourceId, entitySlug] = key.split('\0');
       const localPath = localPathById.get(sourceId)!;
-      const filePath = join(localPath, `${entitySlug}.md`);
+      // resolvePageFilePath, NOT a bare join — non-default sources fence
+      // into `<local_path>/.sources/<id>/<slug>.md`, the same path the
+      // fence-write backstop and put_page write-through compute. A bare
+      // join here diverges fence and DB for non-default sources (#2044).
+      const filePath = resolvePageFilePath(localPath, entitySlug, sourceId);
       const tmpPath = `${filePath}.tmp`;
 
       try {
@@ -269,6 +281,21 @@ async function phaseBFenceFacts(
         const existingFence = parseFactsFence(body);
         const existingKeySet = new Set(existingFence.facts.map(f => `${f.claim}\0${f.source ?? ''}`));
 
+        // Seed appended row_nums from MAX(fence max, DB max) — same #2044
+        // divergence guard as writeFactsToFence. When the fence at the
+        // resolved path is missing/behind but the DB already holds stamped
+        // rows for this slug (legacy wrong-path fence writes), fence-max+1
+        // collides with idx_facts_fence_key on the post-rename UPDATE,
+        // failing the page and leaving fence and DB disagreeing.
+        const dbMaxRows = await engine.executeRaw<{ max: number | string | null }>(
+          `SELECT MAX(row_num) AS max FROM facts
+            WHERE source_id = $1 AND source_markdown_slug = $2`,
+          [sourceId, entitySlug],
+        );
+        const dbMaxRowNum = Number(dbMaxRows[0]?.max ?? 0) || 0;
+        const fenceMaxRowNum = existingFence.facts.reduce((m, f) => Math.max(m, f.rowNum), 0);
+        let nextRowNum = Math.max(fenceMaxRowNum, dbMaxRowNum) + 1;
+
         const assignments: Array<{ id: string; row_num: number }> = [];
         for (const row of group) {
           const key = `${row.fact}\0${row.source ?? ''}`;
@@ -291,6 +318,7 @@ async function phaseBFenceFacts(
                 .toISOString().slice(0, 10)
             : undefined;
           const { body: updated, rowNum } = upsertFactRow(body, {
+            rowNum:     nextRowNum++,
             claim:      row.fact,
             kind:       row.kind,
             confidence: row.confidence,
@@ -381,7 +409,7 @@ async function phaseCVerify(
     for (const g of groups) {
       const localPath = localPathById.get(g.source_id);
       if (!localPath) continue;
-      const filePath = join(localPath, `${g.source_markdown_slug}.md`);
+      const filePath = resolvePageFilePath(localPath, g.source_markdown_slug, g.source_id);
       if (!existsSync(filePath)) {
         mismatches.push(`${g.source_markdown_slug} (file missing)`);
         continue;

src/core/chunkers/code.ts

@@ -18,9 +18,8 @@
  * at runtime.
  */
 
-import { chunkText as recursiveChunk, capByEstimatedTokens, DEFAULT_MAX_EST_TOKENS } from './recursive.ts';
+import { chunkText as recursiveChunk } from './recursive.ts';
 import { buildQualifiedName } from './qualified-names.ts';
-import { estimateEmbeddingTokens } from '../cjk.ts';
 
 // Embed the tree-sitter runtime + per-language grammars as files.
 // `with { type: 'file' }` returns a path (string) at runtime. Bun bundles
@@ -112,15 +111,7 @@ import G_ZIG from '../../assets/wasm/grammars/tree-sitter-zig.wasm' with { type:
 // chunks get the new columns populated. Without this, the v28 backfill
 // gives every existing chunk a search_vector but subsequent Layer 5 AST
 // work would silently no-op.
-//
-// v5: estimated-token hard cap on AST-path chunks (capCodeChunks). A node
-// splitLargeNode can't subdivide (giant single-statement function, huge
-// literal) previously shipped WHOLE regardless of size and could overflow
-// strict per-request embedding-token limits (local llama-server crashes
-// past ~2,050 tokens, measured). Mirrors the markdown
-// chunker's v4 cap; fallback-path chunks are already capped inside
-// recursiveChunk.
-export const CHUNKER_VERSION = 5;
+export const CHUNKER_VERSION = 4;
 
 // Lazy-loaded tree-sitter module (v0.22.x API: Parser is default export)
 let Parser: typeof import('web-tree-sitter') | null = null;
@@ -717,7 +708,7 @@ export async function chunkCodeTextFull(
     if (chunks.length === 0) {
       return { chunks: fallbackChunks(source, filePath, language, opts), edges: rawEdges };
     }
-    return { chunks: capCodeChunks(mergeSmallSiblings(chunks, chunkTarget)), edges: rawEdges };
+    return { chunks: mergeSmallSiblings(chunks, chunkTarget), edges: rawEdges };
   } catch {
     return { chunks: fallbackChunks(source, filePath, language, opts), edges: [] };
   } finally {
@@ -800,33 +791,6 @@ function mergeSmallSiblings(chunks: CodeChunk[], chunkTarget: number): CodeChunk
   return merged;
 }
 
-/**
- * v5 final safety pass for AST-path chunks: split any chunk whose
- * ESTIMATED embedding tokens (conservative per-char-class heuristic,
- * cjk.ts) exceed DEFAULT_MAX_EST_TOKENS. Reaches chunks the AST logic
- * can't subdivide — splitLargeNode returns [] for nodes with < 2 body
- * children (giant single-statement functions, huge literals), which
- * previously shipped whole at any size.
- *
- * Split pieces inherit the source chunk's metadata verbatim; start/end
- * lines become approximate for pieces after the first. Acceptable —
- * these chunks exist for embedding + retrieval, and the alternative was
- * an embedding request the server rejects (or worse, crashes on).
- */
-function capCodeChunks(chunks: CodeChunk[]): CodeChunk[] {
-  if (chunks.every((c) => estimateEmbeddingTokens(c.text) <= DEFAULT_MAX_EST_TOKENS)) {
-    return chunks;
-  }
-  const out: CodeChunk[] = [];
-  for (const c of chunks) {
-    const pieces = capByEstimatedTokens(c.text, DEFAULT_MAX_EST_TOKENS);
-    for (const piece of pieces) {
-      out.push({ ...c, text: piece, index: out.length, metadata: { ...c.metadata } });
-    }
-  }
-  return out;
-}
-
 function buildMergedChunk(group: CodeChunk[], index: number): CodeChunk {
   const first = group[0]!;
   const last = group[group.length - 1]!;

src/core/chunkers/recursive.ts

@@ -17,13 +17,7 @@
  * Lossless invariant: non-overlapping portions reassemble to original.
  */
 
-import {
-  countCJKAwareWords,
-  CJK_SENTENCE_DELIMITERS,
-  CJK_CLAUSE_DELIMITERS,
-  charEmbedTokenWeight,
-  estimateEmbeddingTokens,
-} from '../cjk.ts';
+import { countCJKAwareWords, CJK_SENTENCE_DELIMITERS, CJK_CLAUSE_DELIMITERS } from '../cjk.ts';
 
 /**
  * Markdown chunker version. Folded into the per-page chunker_version column
@@ -39,20 +33,8 @@ import {
  * re-embed (not re-chunk) so existing pages pick up the wrapper on the
  * post-upgrade reembed sweep. See
  * `src/core/contextual-retrieval-service.ts`.
- *
- * v4: estimated-token hard cap + whitespace-word undercount fix. The word
- * pipeline counted a 150-char URL as ONE whitespace word, so URL/phone/
- * email-dense docs (CJK density < 0.30 → whitespace fallback) produced
- * 3-4K-char chunks that overflow strict per-request embedding-token
- * limits (measured: local llama-server crashes past ~2,050 tokens; URL
- * soup tokenizes at ~1.6 chars/token). Two changes:
- *   1. countWords() floors the count at ceil(nonWhitespaceChars/6) so a
- *      URL counts roughly per-character, not as one word.
- *   2. capByEstimatedTokens() final pass guarantees every chunk fits
- *      `maxTokens` (default 1500) under a conservative per-char-class
- *      token estimate, regardless of how word counting misjudged it.
  */
-export const MARKDOWN_CHUNKER_VERSION = 4;
+export const MARKDOWN_CHUNKER_VERSION = 3;
 
 const DELIMITERS: string[][] = [
   ['\n\n'],                          // L0: paragraphs
@@ -66,20 +48,8 @@ export interface ChunkOptions {
   chunkSize?: number;    // target words per chunk (default 300)
   chunkOverlap?: number; // overlap words (default 50)
   maxChars?: number;     // hard cap on any chunk's char length (default 6000)
-  /**
-   * v4: hard cap on any chunk's ESTIMATED embedding tokens (default 1500).
-   * Estimate = conservative per-char-class weights (see cjk.ts
-   * estimateEmbeddingTokens) — deliberately high, so the real tokenizer
-   * count stays below this value. Default leaves headroom for the
-   * contextual-retrieval wrapper (≤ ~630 chars) under a ~2,050-token
-   * per-request embedding server limit.
-   */
-  maxTokens?: number;
 }
 
-/** v4 default for ChunkOptions.maxTokens — see the field doc above. */
-export const DEFAULT_MAX_EST_TOKENS = 1500;
-
 export interface TextChunk {
   text: string;
   index: number;
@@ -103,7 +73,6 @@ export function chunkText(text: string, opts?: ChunkOptions): TextChunk[] {
   const chunkSize = opts?.chunkSize || 300;
   const chunkOverlap = opts?.chunkOverlap || 50;
   const maxChars = opts?.maxChars || 6000;
-  const maxTokens = opts?.maxTokens || DEFAULT_MAX_EST_TOKENS;
 
   if (!text || text.trim().length === 0) return [];
 
@@ -120,9 +89,8 @@ export function chunkText(text: string, opts?: ChunkOptions): TextChunk[] {
 
   const wordCount = countWords(stripped);
   if (wordCount <= chunkSize) {
-    // Single-chunk path: still apply the maxChars + maxTokens caps.
-    const capped = capByChars(stripped.trim(), maxChars)
-      .flatMap((t) => capByEstimatedTokens(t, maxTokens));
+    // Single-chunk path: still apply the maxChars cap.
+    const capped = capByChars(stripped.trim(), maxChars);
     return capped.map((t, i) => ({ text: t, index: i }));
   }
 
@@ -133,14 +101,9 @@ export function chunkText(text: string, opts?: ChunkOptions): TextChunk[] {
   // v0.32.7: hard char cap. Catches pathological CJK + whitespace-less text
   // that the word-level pipeline can't bound (a single Chinese paragraph can
   // exceed 8192 OpenAI embedding tokens at any word count).
-  // v4: estimated-token cap on top — the char cap alone passes token-dense
-  // content (URL soup at ~1.6 chars/token) that overflows strict embedding
-  // server limits.
   const capped: string[] = [];
   for (const chunk of withOverlap) {
-    for (const piece of capByChars(chunk.trim(), maxChars)) {
-      capped.push(...capByEstimatedTokens(piece, maxTokens));
-    }
+    capped.push(...capByChars(chunk.trim(), maxChars));
   }
   return capped.map((t, i) => ({ text: t, index: i }));
 }
@@ -169,68 +132,6 @@ function capByChars(text: string, maxChars: number): string[] {
   return out;
 }
 
-/**
- * How far back (in chars) the token cap looks for a friendly cut point
- * before falling back to a hard cut. 300 covers typical rollup/list line
- * lengths so forced splits land at line starts, not mid-URL.
- */
-const TOKEN_CAP_CUT_LOOKBACK = 300;
-
-/**
- * v4: hard-cap a chunk's ESTIMATED embedding tokens. Final safety pass —
- * runs after capByChars on every chunk, so no upstream miscounting
- * (whitespace-word fallback, overlap inflation, char-cap survivors) can
- * emit a chunk past `maxTokens`.
- *
- * Cut placement prefers, within the last TOKEN_CAP_CUT_LOOKBACK chars of
- * the window: a newline, then any whitespace, then a hard cut. This keeps
- * forced splits off mid-line/mid-URL positions for list-shaped content
- * and inside code fences. No overlap is added (pieces stay lossless
- * modulo the trims the char cap already applies).
- *
- * @internal exported for the code chunker (code.ts) and tests.
- */
-export function capByEstimatedTokens(text: string, maxTokens: number): string[] {
-  if (text.length === 0) return [];
-  if (estimateEmbeddingTokens(text) <= maxTokens) return [text];
-
-  const out: string[] = [];
-  let start = 0;
-  while (start < text.length) {
-    // Greedily extend the window until the next char would break the cap.
-    // Always take at least one char so the loop makes forward progress.
-    let est = 0;
-    let end = start;
-    while (end < text.length) {
-      const w = charEmbedTokenWeight(text.charCodeAt(end));
-      if (est + w > maxTokens && end > start) break;
-      est += w;
-      end++;
-    }
-
-    if (end < text.length) {
-      const windowStart = Math.max(start + 1, end - TOKEN_CAP_CUT_LOOKBACK);
-      let cut = text.lastIndexOf('\n', end - 1);
-      if (cut < windowStart) {
-        cut = -1;
-        for (let i = end - 1; i >= windowStart; i--) {
-          const code = text.charCodeAt(i);
-          if (code === 0x20 || (code >= 0x09 && code <= 0x0d)) {
-            cut = i;
-            break;
-          }
-        }
-      }
-      if (cut >= windowStart) end = cut + 1;
-    }
-
-    const slice = text.slice(start, end).trim();
-    if (slice.length > 0) out.push(slice);
-    start = end;
-  }
-  return out;
-}
-
 function recursiveSplit(text: string, level: number, target: number): string[] {
   if (level >= DELIMITERS.length) {
     // Level 4: split on whitespace
@@ -416,19 +317,7 @@ function extractTrailingContext(text: string, targetWords: number): string {
  * Delegated to src/core/cjk.ts so the slugify whitelist, expansion
  * detection, and PGLite keyword fallback all agree on what "CJK enough"
  * means.
- *
- * v4: floored at ceil(nonWhitespaceChars/6). The whitespace fallback
- * counts a 150-char URL as ONE word, so URL/phone/email-dense docs
- * (whose ASCII mass pushes CJK density below the 0.30 threshold) were
- * sized at a fraction of their real bulk and merged into 3-4K-char
- * chunks. The floor makes long whitespace-less runs count roughly
- * per-character while leaving normal Latin prose untouched (average
- * English word ≈ 5 chars < 6, so the whitespace count still wins).
- * Kept local to the chunker — search/expansion.ts keeps the original
- * countCJKAwareWords semantics for its query-length check.
  */
 function countWords(text: string): number {
-  const cjkAware = countCJKAwareWords(text);
-  const nonWhitespace = text.replace(/\s/g, '').length;
-  return Math.max(cjkAware, Math.ceil(nonWhitespace / 6));
+  return countCJKAwareWords(text);
 }

src/core/cjk.ts

@@ -65,64 +65,3 @@ export function countCJKAwareWords(s: string): number {
 export function escapeLikePattern(s: string): string {
   return s.replace(/\\/g, '\\\\').replace(/%/g, '\\%').replace(/_/g, '\\_');
 }
-
-/**
- * Conservative per-char-class embedding-token weights (markdown chunker v4).
- *
- * Why this exists: the chunker's "word" counting drastically UNDER-counts
- * whitespace-less ASCII runs (a 150-char URL = 1 whitespace word), so
- * word-based size targets can emit chunks that overflow an embedding
- * server's per-request token limit. Measured on a local Qwen3-embedding
- * llama-server stack:
- *   - URL/phone/email-dense text tokenizes at ~1.6 chars/token
- *   - base64-ish / minified blobs approach ~1.3 chars/token (worst case)
- *   - Korean prose tokenizes NO WORSE than 1 char/token in practice
- *
- * Weights are deliberately HIGH (tokens are overestimated) so any cap
- * based on this estimate is safe against real tokenizers:
- *   - CJK char        → 1.0 token  (real CJK prose is cheaper)
- *   - other non-space → 0.75 token (≈1.33 chars/token, covers base64)
- *   - whitespace      → 0.1 token  (mostly folds into neighbor tokens)
- */
-export const EMBED_TOKEN_WEIGHT_CJK = 1.0;
-export const EMBED_TOKEN_WEIGHT_OTHER = 0.75;
-export const EMBED_TOKEN_WEIGHT_WS = 0.1;
-
-/** BMP CJK check by UTF-16 code unit — same ranges as CJK_SLUG_CHARS. */
-export function isCJKCodeUnit(code: number): boolean {
-  return (
-    (code >= 0x4e00 && code <= 0x9fff) || // Han
-    (code >= 0x3040 && code <= 0x309f) || // Hiragana
-    (code >= 0x30a0 && code <= 0x30ff) || // Katakana
-    (code >= 0xac00 && code <= 0xd7af)    // Hangul Syllables
-  );
-}
-
-/**
- * Per-code-unit token weight. Unrecognized whitespace (exotic Unicode
- * spaces) intentionally falls into OTHER — that only overestimates.
- */
-export function charEmbedTokenWeight(code: number): number {
-  if (isCJKCodeUnit(code)) return EMBED_TOKEN_WEIGHT_CJK;
-  if (
-    code === 0x20 || (code >= 0x09 && code <= 0x0d) ||
-    code === 0xa0 || code === 0x3000
-  ) {
-    return EMBED_TOKEN_WEIGHT_WS;
-  }
-  return EMBED_TOKEN_WEIGHT_OTHER;
-}
-
-/**
- * Tokenizer-free embedding-token estimate (conservative overestimate).
- * See weight docs above. Astral chars count as 2 OTHER code units —
- * another overestimate, which is the safe direction.
- */
-export function estimateEmbeddingTokens(s: string): number {
-  if (s.length === 0) return 0;
-  let est = 0;
-  for (let i = 0; i < s.length; i++) {
-    est += charEmbedTokenWeight(s.charCodeAt(i));
-  }
-  return Math.ceil(est);
-}

src/core/cycle/extract-facts.ts

@@ -176,9 +176,11 @@ export async function runExtractFacts(
   if (legacyCount > 0) {
     result.guardTriggered = true;
     result.warnings.push(
-      `extract_facts: ${legacyCount} legacy v0.31 fact rows pending fence backfill. ` +
-      `Run \`gbrain apply-migrations --yes\` to complete v0_32_2 before this phase ` +
-      `can safely reconcile fence → DB.`,
+      `extract_facts: ${legacyCount} legacy fact rows pending fence backfill ` +
+      `(row_num IS NULL — v0.31 rows or remote extract_facts deposits that ` +
+      `predate the fence backstop). Run \`gbrain facts fence-backfill\` ` +
+      `(idempotent, re-runnable) before this phase can safely reconcile ` +
+      `fence → DB.`,
     );
     return result;
   }

src/core/engine.ts

@@ -1739,13 +1739,14 @@ export interface BrainEngine {
    * single-row supersede flow because fence reconciliation is the canonical
    * source-of-truth direction, not the consolidator path.
    *
-   * Insertion is atomic per call: all rows commit in a single transaction
-   * or none commit (the transaction rolls back on any constraint
-   * violation, e.g. the v51 partial UNIQUE index on
-   * `(source_id, source_markdown_slug, row_num)`).
+   * Insertion runs in a single transaction. A collision on the v51
+   * partial UNIQUE index `(source_id, source_markdown_slug, row_num)`
+   * skips ONLY that row (ON CONFLICT DO NOTHING, #2044) — the rest of
+   * the batch still commits, so a redundant deposit against an
+   * already-indexed fence row is idempotent instead of a hard failure.
    *
-   * Returns the inserted ids in input-order so callers can correlate
-   * fence-row → DB-id without a separate lookup.
+   * Returns the inserted ids in input-order (colliding rows omitted) so
+   * callers can correlate fence-row → DB-id without a separate lookup.
    */
   insertFacts(
     rows: Array<NewFact & { row_num: number; source_markdown_slug: string }>,

src/core/facts/fence-write.ts

@@ -218,11 +218,27 @@ export async function writeFactsToFence(
       }
 
       // 2. Upsert each fact onto the fence in input order. row_num
-      //    monotonically increases (max-existing + 1 per call, append-only).
+      //    monotonically increases, append-only, seeded from the MAX of
+      //    the fence and the DB index (#2044): when fence and DB have
+      //    diverged (e.g. legacy writes that stamped DB rows against a
+      //    fence at a path this code no longer reads), fence-max+1 can
+      //    collide with an existing DB row_num, tripping
+      //    idx_facts_fence_key and rolling back the whole batch.
+      const dbMaxRows = await engine.executeRaw<{ max: number | string | null }>(
+        `SELECT MAX(row_num) AS max FROM facts
+          WHERE source_id = $1 AND source_markdown_slug = $2`,
+        [target.sourceId, target.slug],
+      );
+      const dbMaxRowNum = Number(dbMaxRows[0]?.max ?? 0) || 0;
+      const fenceMaxRowNum = parseFactsFence(body).facts
+        .reduce((m, f) => Math.max(m, f.rowNum), 0);
+      let nextRowNum = Math.max(fenceMaxRowNum, dbMaxRowNum) + 1;
+
       const assignedRowNums: number[] = [];
       for (const f of facts) {
         const validFromStr = (f.validFrom ?? new Date()).toISOString().slice(0, 10);
         const { body: updated, rowNum } = upsertFactRow(body, {
+          rowNum:      nextRowNum++,
           claim:       f.fact,
           kind:        (f.kind ?? 'fact') as 'fact' | 'event' | 'preference' | 'commitment' | 'belief',
           confidence:  f.confidence ?? 1.0,

src/core/pglite-engine.ts

@@ -4102,11 +4102,13 @@ export class PGLiteEngine implements BrainEngine {
   ): Promise<{ inserted: number; ids: number[] }> {
     if (rows.length === 0) return { inserted: 0, ids: [] };
 
-    // Single transaction so the v51 partial UNIQUE index can roll back the
-    // whole batch on constraint violation. Per-row INSERTs (not multi-row
-    // VALUES) keep the embedding-vs-no-embedding branching readable; batch
-    // sizes are small (5-30 rows per page in practice) so the loop overhead
-    // is negligible vs the embedding compute cost.
+    // Single transaction; per-row INSERTs (not multi-row VALUES) keep the
+    // embedding-vs-no-embedding branching readable; batch sizes are small
+    // (5-30 rows per page in practice) so the loop overhead is negligible
+    // vs the embedding compute cost. #2044: ON CONFLICT DO NOTHING on the
+    // v51 partial UNIQUE index makes a residual fence/DB row_num collision
+    // skip that row instead of rolling back the whole batch (parity with
+    // postgres-engine.ts).
     const ids = await this.db.transaction(async (tx) => {
       const out: number[] = [];
       for (const input of rows) {
@@ -4149,7 +4151,11 @@ export class PGLiteEngine implements BrainEngine {
                  $14, $15,
                  $16, $17, $18, $19,
                  $20
-               ) RETURNING id`
+               )
+               ON CONFLICT (source_id, source_markdown_slug, row_num)
+                 WHERE row_num IS NOT NULL
+                 DO NOTHING
+               RETURNING id`
             : `INSERT INTO facts (
                  source_id, entity_slug, fact, kind, visibility, notability, context,
                  valid_from, valid_until, source, source_session, confidence,
@@ -4163,12 +4169,16 @@ export class PGLiteEngine implements BrainEngine {
                  $15, $16,
                  $17, $18, $19, $20,
                  $21
-               ) RETURNING id`,
+               )
+               ON CONFLICT (source_id, source_markdown_slug, row_num)
+                 WHERE row_num IS NOT NULL
+                 DO NOTHING
+               RETURNING id`,
           embedStr === null
             ? [ctx.source_id, entitySlug, input.fact, kind, visibility, notability, context, validFrom, validUntil, input.source, sourceSession, confidence, embeddedAt, input.row_num, input.source_markdown_slug, claimMetric, claimValue, claimUnit, claimPeriod, eventType]
             : [ctx.source_id, entitySlug, input.fact, kind, visibility, notability, context, validFrom, validUntil, input.source, sourceSession, confidence, embedStr, embeddedAt, input.row_num, input.source_markdown_slug, claimMetric, claimValue, claimUnit, claimPeriod, eventType],
         );
-        out.push(ins.rows[0].id);
+        if (ins.rows[0]) out.push(ins.rows[0].id);
       }
       return out;
     });

src/core/postgres-engine.ts

@@ -4302,10 +4302,12 @@ export class PostgresEngine implements BrainEngine {
     // ONCE per process so the cast matches the actual column type
     // (halfvec vs vector). The probe is cached after first call.
     const castSuffix = await this.resolveFactsEmbeddingCast();
-    // Single transaction so the v51 partial UNIQUE index can roll back
-    // the whole batch on constraint violation. Per-row INSERTs (not
-    // multi-row VALUES) keep the embedding-vs-no-embedding branching
-    // readable; batch sizes are small (5-30 rows per page in practice).
+    // Single transaction; per-row INSERTs (not multi-row VALUES) keep the
+    // embedding-vs-no-embedding branching readable; batch sizes are small
+    // (5-30 rows per page in practice). #2044: ON CONFLICT DO NOTHING on
+    // the v51 partial UNIQUE index makes a residual fence/DB row_num
+    // collision skip that row instead of rolling back the whole batch —
+    // the fence stays system-of-record and reconciliation catches up.
     // No supersede flow in this path — fence reconciliation is the
     // canonical source-of-truth direction, not the consolidator path.
     const ids = await sql.begin(async (tx) => {
@@ -4346,9 +4348,13 @@ export class PostgresEngine implements BrainEngine {
             ${input.row_num}, ${input.source_markdown_slug},
             ${claimMetric}, ${claimValue}, ${claimUnit}, ${claimPeriod},
             ${eventType}
-          ) RETURNING id
+          )
+          ON CONFLICT (source_id, source_markdown_slug, row_num)
+            WHERE row_num IS NOT NULL
+            DO NOTHING
+          RETURNING id
         `;
-        out.push(Number(ins[0].id));
+        if (ins[0]) out.push(Number(ins[0].id));
       }
       return out;
     });

test/chunker-version-gate.test.ts

@@ -15,22 +15,19 @@ import { describe, test, expect } from 'bun:test';
 import { CHUNKER_VERSION } from '../src/core/chunkers/code.ts';
 
 describe('Layer 12 — CHUNKER_VERSION constant', () => {
-  test('bumped to 5 for the estimated-token hard cap', () => {
+  test('bumped to 4 for Cathedral II', () => {
     // v3: v0.19.0 Chonkie parity (tokenizer + small-sibling merge).
     // v4: v0.20.0 Cathedral II (qualified names + parent scope + doc_comment
     //     + fence extraction + chunk-grain FTS). Folded into content_hash
     //     so any bump forces clean re-chunks on next sync.
-    // v5: estimated-token hard cap on AST-path chunks (capCodeChunks) so
-    //     un-subdividable giant nodes can't overflow strict embedding
-    //     server token limits.
-    expect(CHUNKER_VERSION).toBe(5);
+    expect(CHUNKER_VERSION).toBe(4);
   });
 
   test('is stable across imports (not recomputed at call time)', async () => {
     const a = (await import('../src/core/chunkers/code.ts')).CHUNKER_VERSION;
     const b = (await import('../src/core/chunkers/code.ts')).CHUNKER_VERSION;
     expect(a).toBe(b);
-    expect(a).toBe(5);
+    expect(a).toBe(4);
   });
 });
 

test/chunkers/code.test.ts

@@ -10,8 +10,8 @@ import { describe, test, expect } from 'bun:test';
 import { chunkCodeText, detectCodeLanguage, CHUNKER_VERSION } from '../../src/core/chunkers/code.ts';
 
 describe('CHUNKER_VERSION', () => {
-  test('v5: estimated-token hard cap on AST-path chunks', () => {
-    expect(CHUNKER_VERSION).toBe(5);
+  test('v0.20.0 Cathedral II Layer 12 bumped to 4', () => {
+    expect(CHUNKER_VERSION).toBe(4);
   });
 });
 

test/chunkers/recursive.test.ts

@@ -135,14 +135,13 @@ describe('Recursive Text Chunker', () => {
 });
 
 describe('CJK chunking (v0.32.7)', () => {
-  test('MARKDOWN_CHUNKER_VERSION is 4', async () => {
+  test('MARKDOWN_CHUNKER_VERSION is 3', async () => {
     // v0.40.3.0: bumped 2→3 to signal the post-upgrade reembed sweep that
-    // contextual retrieval wrapping is now applied at embed time.
-    // v4: estimated-token hard cap + whitespace-word undercount floor
-    // (URL-dense docs produced chunks past strict embedding server token
-    // limits). Boundary change → forces re-chunk for chunker_version < 4.
+    // contextual retrieval wrapping is now applied at embed time. Chunk
+    // boundaries themselves are unchanged; the bump forces re-embed for
+    // pages where chunker_version < 3.
     const mod = await import('../../src/core/chunkers/recursive.ts');
-    expect(mod.MARKDOWN_CHUNKER_VERSION).toBe(4);
+    expect(mod.MARKDOWN_CHUNKER_VERSION).toBe(3);
   });
 
   test('long pure-Chinese paragraph splits into multiple chunks', () => {

test/chunkers/token-cap.test.ts

@@ -1,195 +0,0 @@
-/**
- * Markdown chunker v4 / code chunker v5 — estimated-token hard cap
- * regression tests.
- *
- * Reproduces a field failure: a local llama-server embedding backend
- * (`-ub 2048`) crashes deterministically (trace/BPT trap → EOF at the
- * client) when a single chunk exceeds ~2,050 real tokens. Two content
- * shapes triggered it:
- *
- *   1. Korean docs carrying one long source URL per line.
- *      The URLs' ASCII mass pushes CJK density below 0.30, flipping
- *      countCJKAwareWords to whitespace counting, where a 150-char URL
- *      counts as ONE word → chunks ballooned to 3-4K chars ≈ 2,000+
- *      real tokens (URL soup tokenizes at ~1.6 chars/token).
- *
- *   2. Large JSON code blocks (~7K chars) that the word pipeline
- *      undercounts the same way (few whitespace tokens).
- *
- * The fix: every emitted chunk must satisfy
- *   estimateEmbeddingTokens(chunk) <= maxTokens (default 1500)
- * where the estimate deliberately OVERSTATES real tokenizer counts.
- */
-
-import { describe, test, expect } from 'bun:test';
-import { chunkText, capByEstimatedTokens, DEFAULT_MAX_EST_TOKENS } from '../../src/core/chunkers/recursive.ts';
-import { chunkCodeText } from '../../src/core/chunkers/code.ts';
-import { estimateEmbeddingTokens } from '../../src/core/cjk.ts';
-
-/** Synthesize the failing shape: Korean rollup lines each ending in a long Notion URL. */
-function urlDenseKoreanRollup(lines: number): string {
-  const out: string[] = ['# 링크가 줄마다 붙는 한국어 예시 문서', ''];
-  for (let i = 0; i < lines; i++) {
-    const hex32 = (i * 2654435761 >>> 0).toString(16).padStart(8, '0').repeat(4);
-    out.push(
-      `- **항목 ${i}**: 이 줄은 청커 동작 검증을 위한 의미 없는 한국어 예시 문장입니다 · 전화 000-0000-${String(1000 + i)} · ` +
-      `이메일 user${i}@example.com · 링크: https://docs.example.com/pages/${hex32}?v=abcdef0123456789&ref=sample`,
-    );
-  }
-  return out.join('\n');
-}
-
-/** Synthesize a large pretty-printed JSON block with CJK values. */
-function bigJsonBlock(targetChars: number): string {
-  const entries: string[] = [];
-  let i = 0;
-  let len = 0;
-  while (len < targetChars) {
-    const row =
-      `  "item_${i}": { "name": "예시-${i}", "url": "https://example.com/api/v2/items/${i}?token=abc${i}def", "qty": ${i % 100}, "memo": "한국어 값이 섞인 예시 데이터" }`;
-    entries.push(row);
-    len += row.length;
-    i++;
-  }
-  return `{\n${entries.join(',\n')}\n}`;
-}
-
-describe('v4 estimated-token cap — URL-dense Korean doc (field-failure shape)', () => {
-  test('every chunk stays under the estimated-token cap', () => {
-    const md = urlDenseKoreanRollup(60);
-    const chunks = chunkText(md);
-    expect(chunks.length).toBeGreaterThan(0);
-    for (const c of chunks) {
-      expect(estimateEmbeddingTokens(c.text)).toBeLessThanOrEqual(DEFAULT_MAX_EST_TOKENS);
-    }
-  });
-
-  test('no chunk reaches the measured 3K-char danger zone for URL soup', () => {
-    const md = urlDenseKoreanRollup(60);
-    const chunks = chunkText(md);
-    // 1500 est tokens at the OTHER weight (0.75/char) bounds chunks to
-    // ~2,000 chars for pure ASCII — well under the ~3,300 chars where
-    // URL-dense content crosses ~2,050 real tokens (1.6 chars/token).
-    for (const c of chunks) {
-      expect(c.text.length).toBeLessThanOrEqual(2600);
-    }
-  });
-
-  test('content is preserved (no lines dropped by the cap)', () => {
-    const md = urlDenseKoreanRollup(60);
-    const chunks = chunkText(md);
-    const joined = chunks.map((c) => c.text).join('\n');
-    // Spot-check first / middle / last rollup lines survive chunking.
-    for (const marker of ['항목 0', '항목 30', '항목 59']) {
-      expect(joined).toContain(marker);
-    }
-  });
-});
-
-describe('v4 estimated-token cap — large JSON blocks', () => {
-  test('7K-char pretty JSON through the prose path stays under the cap', () => {
-    const md = `설정 파일 원문 보존:\n\n\`\`\`\n${bigJsonBlock(7000)}\n\`\`\`\n`;
-    const chunks = chunkText(md);
-    expect(chunks.length).toBeGreaterThan(1);
-    for (const c of chunks) {
-      expect(estimateEmbeddingTokens(c.text)).toBeLessThanOrEqual(DEFAULT_MAX_EST_TOKENS);
-    }
-  });
-
-  test('7K-char minified JSON (single whitespace-less token) stays under the cap', () => {
-    const minified = bigJsonBlock(7000).replace(/\n\s*/g, '');
-    const chunks = chunkText(minified);
-    expect(chunks.length).toBeGreaterThan(1);
-    for (const c of chunks) {
-      expect(estimateEmbeddingTokens(c.text)).toBeLessThanOrEqual(DEFAULT_MAX_EST_TOKENS);
-    }
-  });
-
-  test('json fence via the code chunker stays under the cap (+header slack)', async () => {
-    const chunks = await chunkCodeText(bigJsonBlock(7000), 'fence.json');
-    expect(chunks.length).toBeGreaterThan(0);
-    for (const c of chunks) {
-      // buildChunk prepends a short "[JSON] fence.json:…" header AFTER the
-      // body-level cap; allow ~60 est tokens of header slack. Real-token
-      // safety margin (2,050 − overestimated 1,500) absorbs this easily.
-      expect(estimateEmbeddingTokens(c.text)).toBeLessThanOrEqual(DEFAULT_MAX_EST_TOKENS + 60);
-    }
-  });
-});
-
-describe('v4 word-count floor — behavior preserved for normal content', () => {
-  test('Latin prose chunking is unchanged by the floor (avg word < 6 chars)', () => {
-    const prose = Array.from({ length: 120 }, (_, i) =>
-      `This is sentence number ${i} and it talks about ordinary things in plain words.`,
-    ).join(' ');
-    const chunks = chunkText(prose);
-    // Historical behavior: ~1,560 whitespace words → multiple ~300-word chunks.
-    expect(chunks.length).toBeGreaterThan(3);
-    for (const c of chunks) {
-      const words = c.text.split(/\s+/).length;
-      expect(words).toBeLessThanOrEqual(300 * 1.5 + 50); // merge cap + overlap
-    }
-  });
-
-  test('Korean prose (CJK-dense, no URLs) never triggers the token cap', () => {
-    const prose = Array.from({ length: 80 }, (_, i) =>
-      `이 문장은 순수 한국어 산문의 청킹 동작을 확인하기 위한 ${i}번째 예시 문장입니다.`,
-    ).join(' ');
-    const chunks = chunkText(prose);
-    expect(chunks.length).toBeGreaterThan(1);
-    for (const c of chunks) {
-      // CJK-dense chunks are char-counted (≈450 max) — nowhere near 1500.
-      expect(estimateEmbeddingTokens(c.text)).toBeLessThanOrEqual(700);
-    }
-  });
-});
-
-describe('capByEstimatedTokens unit behavior', () => {
-  test('returns input unchanged when under the cap', () => {
-    expect(capByEstimatedTokens('short text', 1500)).toEqual(['short text']);
-    expect(capByEstimatedTokens('', 1500)).toEqual([]);
-  });
-
-  test('prefers newline cut points within the lookback window', () => {
-    const line = 'x'.repeat(100);
-    const text = Array.from({ length: 40 }, () => line).join('\n');
-    const pieces = capByEstimatedTokens(text, 1000);
-    expect(pieces.length).toBeGreaterThan(1);
-    for (const p of pieces) {
-      // Every piece should be whole lines (multiples of the 100-char line).
-      for (const l of p.split('\n')) {
-        expect(l).toBe(line);
-      }
-    }
-  });
-
-  test('makes forward progress on whitespace-less input (hard cut)', () => {
-    const blob = 'a'.repeat(10_000);
-    const pieces = capByEstimatedTokens(blob, 1000);
-    expect(pieces.length).toBeGreaterThan(1);
-    expect(pieces.join('')).toBe(blob);
-    for (const p of pieces) {
-      expect(estimateEmbeddingTokens(p)).toBeLessThanOrEqual(1000);
-    }
-  });
-});
-
-describe('estimateEmbeddingTokens — weight sanity', () => {
-  test('overestimates URL-dense ASCII (0.75/char ≥ measured ~0.63/char)', () => {
-    const url = 'https://docs.example.com/pages/a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4?v=abc&ref=sample';
-    const est = estimateEmbeddingTokens(url);
-    expect(est).toBeGreaterThanOrEqual(Math.floor(url.length * 0.7));
-  });
-
-  test('counts CJK at 1 token/char', () => {
-    expect(estimateEmbeddingTokens('가나다라마')).toBe(5);
-  });
-
-  test('whitespace is nearly free', () => {
-    expect(estimateEmbeddingTokens('   \n\t  ')).toBeLessThanOrEqual(1);
-  });
-
-  test('empty string is 0', () => {
-    expect(estimateEmbeddingTokens('')).toBe(0);
-  });
-});

test/extract-facts-phase.test.ts

@@ -304,7 +304,9 @@ describe('runExtractFacts — empty-fence guard (Codex R2-#7)', () => {
     expect(r.legacyRowsPending).toBe(1);
     expect(r.factsInserted).toBe(0);
     expect(r.factsDeleted).toBe(0);
-    expect(r.warnings.some(w => w.includes('apply-migrations'))).toBe(true);
+    // #1867: the remedy hint points at the re-runnable backfill command,
+    // not the one-shot v0_32_2 migration (which the ledger never re-runs).
+    expect(r.warnings.some(w => w.includes('gbrain facts fence-backfill'))).toBe(true);
 
     // Legacy row was NOT touched.
     // eslint-disable-next-line @typescript-eslint/no-explicit-any

test/facts-fence-backfill-command.test.ts

@@ -0,0 +1,133 @@
+/**
+ * #1867 — `gbrain facts fence-backfill` command tests.
+ *
+ * The command re-runs the (idempotent) v0_32_2 phase B on demand so
+ * row_num-NULL backlogs — remote extract_facts deposits that predate
+ * the fence-write backstop — can be cleared without re-running the
+ * one-shot migration. Real PGLite + real tempdir filesystem.
+ */
+
+import { describe, test, expect, beforeAll, afterAll, beforeEach } from 'bun:test';
+import { mkdtempSync, rmSync, existsSync, readFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+
+import { PGLiteEngine } from '../src/core/pglite-engine.ts';
+import { runFactsCommand } from '../src/commands/facts.ts';
+import { phaseBFenceFacts } from '../src/commands/migrations/v0_32_2.ts';
+
+let engine: PGLiteEngine;
+let brainDir: string;
+
+beforeAll(async () => {
+  engine = new PGLiteEngine();
+  await engine.connect({});
+  await engine.initSchema();
+});
+
+afterAll(async () => {
+  await engine.disconnect();
+  try {
+    if (brainDir) rmSync(brainDir, { recursive: true, force: true });
+  } catch { /* best-effort */ }
+});
+
+beforeEach(async () => {
+  brainDir = mkdtempSync(join(tmpdir(), 'facts-backfill-cmd-test-'));
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  await (engine as any).db.query('DELETE FROM facts');
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  await (engine as any).db.query(
+    `UPDATE sources SET local_path = $1 WHERE id = 'default'`,
+    [brainDir],
+  );
+});
+
+async function seedLegacyFact(fact: string): Promise<void> {
+  // The row_num-NULL shape a remote extract_facts deposit leaves behind
+  // when it lands via the legacy DB-only path.
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  await (engine as any).db.query(
+    `INSERT INTO facts (source_id, entity_slug, fact, kind, visibility, notability,
+                        valid_from, source, confidence)
+     VALUES ('default', 'people/alice', $1, 'fact', 'private', 'medium',
+             now(), 'mcp:extract_facts', 1.0)`,
+    [fact],
+  );
+}
+
+describe('gbrain facts fence-backfill', () => {
+  test('fences row_num-NULL rows and stamps the DB', async () => {
+    await seedLegacyFact('Deposited remotely');
+
+    await runFactsCommand(engine, ['fence-backfill']);
+
+    // The fence exists on disk with the claim.
+    const filePath = join(brainDir, 'people/alice.md');
+    expect(existsSync(filePath)).toBe(true);
+    expect(readFileSync(filePath, 'utf-8')).toContain('Deposited remotely');
+
+    // The backlog is cleared: no row_num-NULL rows remain.
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const rows = await (engine as any).db.query(
+      'SELECT row_num, source_markdown_slug FROM facts',
+    );
+    expect(rows.rows).toHaveLength(1);
+    expect(rows.rows[0].row_num).toBe(1);
+    expect(rows.rows[0].source_markdown_slug).toBe('people/alice');
+  });
+
+  test('re-run is a no-op (idempotent)', async () => {
+    await seedLegacyFact('Deposited remotely');
+    await runFactsCommand(engine, ['fence-backfill']);
+    await runFactsCommand(engine, ['fence-backfill']);
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const rows = await (engine as any).db.query('SELECT id FROM facts');
+    expect(rows.rows).toHaveLength(1);
+    const body = readFileSync(join(brainDir, 'people/alice.md'), 'utf-8');
+    expect(body.match(/Deposited remotely/g)).toHaveLength(1);
+  });
+
+  test('--dry-run reports without writing', async () => {
+    await seedLegacyFact('Deposited remotely');
+    await runFactsCommand(engine, ['fence-backfill', '--dry-run']);
+
+    expect(existsSync(join(brainDir, 'people/alice.md'))).toBe(false);
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const rows = await (engine as any).db.query(
+      'SELECT row_num FROM facts',
+    );
+    expect(rows.rows[0].row_num).toBeNull();
+  });
+
+  test('diverged page: appends past the DB row_num max instead of colliding (#2044 class)', async () => {
+    // The #2044 divergence shape the backfill must survive: the DB already
+    // holds stamped rows 1..3 for the slug (legacy wrong-path fence write),
+    // but the fence at the resolved path is missing. Fence-max+1 (= 1) would
+    // collide with the stamped rows on the post-rename UPDATE, failing the
+    // page and leaving the renamed fence disagreeing with the DB.
+    for (let n = 1; n <= 3; n++) {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      await (engine as any).db.query(
+        `INSERT INTO facts (source_id, entity_slug, fact, kind, visibility, notability,
+                            valid_from, source, confidence, row_num, source_markdown_slug)
+         VALUES ('default', 'people/alice', $1, 'fact', 'private', 'medium',
+                 now(), 'mcp:extract_facts', 1.0, $2, 'people/alice')`,
+        [`stamped ${n}`, n],
+      );
+    }
+    await seedLegacyFact('Deposited remotely');
+
+    const result = await phaseBFenceFacts(engine, { dryRun: false });
+    expect(result.status).toBe('complete');
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const rows = await (engine as any).db.query(
+      `SELECT row_num FROM facts WHERE fact = 'Deposited remotely'`,
+    );
+    expect(rows.rows[0].row_num).toBe(4);
+    const body = readFileSync(join(brainDir, 'people/alice.md'), 'utf-8');
+    expect(body).toContain('| 4 | Deposited remotely |');
+  });
+});

test/fence-write.test.ts

@@ -292,6 +292,49 @@ describe('lookupSourceLocalPath', () => {
   });
 });
 
+describe('writeFactsToFence — fence/DB divergence (#2044)', () => {
+  test('seeds row_num past the DB max when the fence lags the DB', async () => {
+    // Simulate the divergence class from #2044: DB rows were stamped with
+    // row_nums against a fence written at a path this code no longer reads
+    // (e.g. the pre-"Local patch 2026-06-11" wrong-path writes). The page
+    // on disk has NO fence, but the DB already holds row_num 1..3 for the
+    // slug. Pre-fix, the next deposit re-assigned row_num=1 from fence
+    // text alone and the whole insertFacts batch failed on
+    // idx_facts_fence_key.
+    for (let n = 1; n <= 3; n++) {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      await (engine as any).db.query(
+        `INSERT INTO facts (source_id, entity_slug, fact, kind, visibility, notability,
+                            valid_from, source, confidence, row_num, source_markdown_slug)
+         VALUES ('default', 'people/dana', $1, 'fact', 'private', 'medium',
+                 now(), 'mcp:extract_facts', 1.0, $2, 'people/dana')`,
+        [`old claim ${n}`, n],
+      );
+    }
+
+    const result = await writeFactsToFence(
+      engine,
+      { sourceId: 'default', localPath: brainDir, slug: 'people/dana' },
+      [baseInput({ fact: 'second deposit' })],
+    );
+
+    expect(result.fenceWriteFailed).toBeUndefined();
+    expect(result.inserted).toBe(1);
+
+    // The new row landed PAST the DB max, not at fence-max+1 (= 1).
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const rows = await (engine as any).db.query(
+      'SELECT row_num FROM facts WHERE id = $1',
+      [result.ids[0]],
+    );
+    expect(rows.rows[0].row_num).toBe(4);
+
+    // And the on-disk fence carries the same row_num — fence and DB agree.
+    const body = readFileSync(join(brainDir, 'people/dana.md'), 'utf-8');
+    expect(body).toContain('| 4 | second deposit |');
+  });
+});
+
 // Cleanup any leftover tempdirs after the whole suite.
 afterAll(() => {
   // No-op: each test cleaned up via the beforeEach; this is a safety net.

test/insert-facts-batch.test.ts

@@ -5,7 +5,7 @@
  *   - Batch insert N rows persists row_num + source_markdown_slug
  *   - Empty batch is a no-op
  *   - Returns ids in input-order
- *   - v51 partial UNIQUE index rolls back the whole batch on a collision
+ *   - v51 partial UNIQUE collision skips only the colliding row (#2044)
  *   - deleteFactsForPage scopes by (source_id, source_markdown_slug);
  *     never touches other pages or pre-v51 NULL-source_markdown_slug rows
  *   - deleteFactsForPage on an empty page returns deleted:0 (idempotent)
@@ -135,30 +135,29 @@ describe('engine.insertFacts — batch insert', () => {
     });
   });
 
-  test('v51 partial UNIQUE index rolls back the whole batch on collision', async () => {
+  test('v51 partial UNIQUE collision skips ONLY the colliding row (#2044)', async () => {
     // Seed row #1 first.
     await engine.insertFacts([fixtureFact(1, { fact: 'seeded' })], { source_id: 'default' });
 
-    // Now try to batch-insert rows that include a colliding row_num=1.
-    let threw = false;
-    try {
-      await engine.insertFacts(
-        [
-          fixtureFact(2, { fact: 'second' }),
-          fixtureFact(1, { fact: 'collides' }),  // row_num=1 on same (source_id, source_markdown_slug)
-          fixtureFact(3, { fact: 'third' }),
-        ],
-        { source_id: 'default' },
-      );
-    } catch {
-      threw = true;
-    }
-    expect(threw).toBe(true);
+    // Batch-insert rows that include a colliding row_num=1. Pre-#2044 this
+    // threw and rolled back the whole batch, making a second remote
+    // extract_facts deposit to an already-fenced page a hard failure. Now
+    // ON CONFLICT DO NOTHING skips the colliding row and keeps the rest.
+    const result = await engine.insertFacts(
+      [
+        fixtureFact(2, { fact: 'second' }),
+        fixtureFact(1, { fact: 'collides' }),  // row_num=1 on same (source_id, source_markdown_slug)
+        fixtureFact(3, { fact: 'third' }),
+      ],
+      { source_id: 'default' },
+    );
+    expect(result.inserted).toBe(2);
+    expect(result.ids).toHaveLength(2);
 
-    // Verify the transaction rolled back — only the seeded row should remain.
+    // The seeded row survives untouched; the colliding claim is skipped.
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     const rows = await (engine as any).db.query('SELECT fact FROM facts ORDER BY id');
-    expect(rows.rows.map((r: { fact: string }) => r.fact)).toEqual(['seeded']);
+    expect(rows.rows.map((r: { fact: string }) => r.fact)).toEqual(['seeded', 'second', 'third']);
   });
 
   test('different source_markdown_slug values DO NOT collide on the same row_num', async () => {