fix(8.0): VFS path-cache instance-scoping + verb totalCount page-cap

Two independent restart/multi-instance correctness bugs.

VFS path cache (A.3): PathResolver keyed the PROCESS-GLOBAL path cache on
`vfs:path:<path>` with no instance scope. Multiple Brainys per process (a
supported pattern) over DIFFERENT storage collided — instance A's `/x → id_A`
satisfied instance B's `stat('/x')` against unrelated storage → stale id →
"Entity not found" (surfaced by metadata-only-comprehensive's VFS stat() once
another VFS test had seeded the cache). Scope every `vfs:path:` key by a
monotonic per-process instance token (the VFS root id is a fixed sentinel, so it
can't disambiguate; the global cache is itself process-scoped so the token
suffices). Scoped the invalidate/prefix-delete paths too, so a branch-switch /
clear / fork on one brain no longer wipes another brain's cache. Cross-instance
sharing was only an optimization and was the collision itself; each instance
keeps its own local pathCache.

Verb totalCount (verb mirror of b2005ff): getVerbsWithPagination returned
`collectedVerbs.length` (the peeked page size, bounded by offset+limit+1) as
totalCount, so getVerbs({limit:1}).totalCount read 1/2 for any non-empty brain
on the unfiltered path. Now returns the authoritative O(1) totalVerbCount
(isNew-gated, visibility-filtered, rehydrated on init); filtered scans keep the
collected length. Regression: tests/unit/storage/getVerbs-totalCount.test.ts
(warm + cold reopen, mirrors the noun test).

metadata-only-comprehensive + vfs-api-wiring integration green; 1471 unit green.

src/storage/baseStorage.ts

@@ -1789,9 +1789,22 @@ export abstract class BaseStorage extends BaseStorageAdapter {
     const paginatedVerbs = collectedVerbs.slice(offset, offset + limit)
     const hasMore = collectedVerbs.length > targetCount
 
+    // totalCount must be the TRUE dataset total, not this peeked page. The verb
+    // type-scan early-terminates at `peekCount = offset + limit + 1`, so
+    // `collectedVerbs.length` only ever reaches the page size + 1 — returning it
+    // made `getVerbs({ pagination: { limit: 1 } }).totalCount` read 1 (or 2) for
+    // any non-empty brain. This is the verb mirror of the noun fix (b2005ff): for
+    // the unfiltered scan the authoritative total is the O(1) `totalVerbCount`
+    // counter (isNew-gated, visibility-filtered, rehydrated on init); `Math.max`
+    // guards a stale counter from under-reporting. A filtered scan has no cheap
+    // exact total, so it keeps the collected length (a lower bound).
+    const totalCount = filter
+      ? collectedVerbs.length
+      : Math.max(this.totalVerbCount, collectedVerbs.length)
+
     return {
       items: paginatedVerbs,
-      totalCount: collectedVerbs.length,  // Accurate count of collected results
+      totalCount,
       hasMore,
       nextCursor: hasMore && paginatedVerbs.length > 0
         ? paginatedVerbs[paginatedVerbs.length - 1].id

src/vfs/PathResolver.ts

@@ -20,12 +20,29 @@ interface PathCacheEntry {
   hits: number  // Track hot paths
 }
 
+/**
+ * Per-process sequence used to scope the PROCESS-GLOBAL path cache to a single
+ * PathResolver instance. The unified path cache (`getGlobalCache()`) is shared
+ * across every Brainy in the process; multiple instances over DIFFERENT storage
+ * are a supported pattern, and the VFS root id is a fixed sentinel, so a path key
+ * with no instance scope let instance A's `/x → id_A` satisfy instance B's
+ * `stat('/x')` against unrelated storage → stale id → "Entity not found". A
+ * monotonic per-process token isolates each instance (the in-memory global cache
+ * is itself process-scoped, so this is sufficient and survives restarts trivially
+ * — the cache is empty then anyway). Cross-instance sharing was only an
+ * optimization and is the very collision this removes; each instance keeps its
+ * own local pathCache.
+ */
+let pathResolverScopeSeq = 0
+
 /**
  * High-performance path resolver with intelligent caching
  */
 export class PathResolver {
   private brain: Brainy
   private rootEntityId: string
+  /** Stable per-instance prefix scoping this resolver's global-cache entries. */
+  private readonly cacheScope: string
 
   // Multi-layer cache system
   private pathCache: Map<string, PathCacheEntry>
@@ -54,6 +71,9 @@ export class PathResolver {
   }) {
     this.brain = brain
     this.rootEntityId = rootEntityId
+    // Scope global-cache keys to this instance so two Brainys in one process
+    // (over different storage) can't read each other's path→id mappings.
+    this.cacheScope = `${rootEntityId}#${++pathResolverScopeSeq}`
 
     // Initialize caches
     this.pathCache = new Map()
@@ -86,7 +106,7 @@ export class PathResolver {
       return this.rootEntityId
     }
 
-    const cacheKey = `vfs:path:${normalizedPath}`
+    const cacheKey = this.globalPathKey(normalizedPath)
 
     // L1: UnifiedCache (global LRU cache, <1ms, works for ALL adapters)
     if (options?.cache !== false) {
@@ -148,6 +168,21 @@ export class PathResolver {
     return entityId
   }
 
+  /**
+   * Build this instance's process-global cache key for a normalized path.
+   * Scoped by {@link cacheScope} so instances over different storage never collide.
+   */
+  private globalPathKey(normalizedPath: string): string {
+    return `vfs:path:${this.cacheScope}:${normalizedPath}`
+  }
+
+  /**
+   * This instance's global-cache key prefix (for scoped prefix deletes).
+   */
+  private globalPathPrefix(): string {
+    return `vfs:path:${this.cacheScope}:`
+  }
+
   /**
    * Full path resolution by traversing the graph
    */
@@ -366,8 +401,9 @@ export class PathResolver {
     this.parentCache.clear()
     this.hotPaths.clear()
 
-    // Clear all VFS entries from UnifiedCache
-    getGlobalCache().deleteByPrefix('vfs:path:')
+    // Clear THIS instance's VFS entries from UnifiedCache (scoped so a branch
+    // switch / clear / fork on one brain can't wipe another brain's cache).
+    getGlobalCache().deleteByPrefix(this.globalPathPrefix())
 
     // Reset statistics (optional but helpful for debugging)
     this.cacheHits = 0
@@ -400,7 +436,7 @@ export class PathResolver {
 
     // CRITICAL FIX: Also invalidate UnifiedCache (global LRU cache)
     // This was missing before, causing stale entity IDs to be returned after delete
-    const cacheKey = `vfs:path:${normalizedPath}`
+    const cacheKey = this.globalPathKey(normalizedPath)
     getGlobalCache().delete(cacheKey)
 
     if (recursive) {
@@ -417,7 +453,7 @@ export class PathResolver {
       }
 
       // CRITICAL FIX: Also invalidate UnifiedCache entries with this prefix
-      const globalCachePrefix = `vfs:path:${prefix}`
+      const globalCachePrefix = this.globalPathKey(prefix)
       getGlobalCache().deleteByPrefix(globalCachePrefix)
     }
   }

tests/unit/storage/getVerbs-totalCount.test.ts

@@ -0,0 +1,94 @@
+/**
+ * @module tests/unit/storage/getVerbs-totalCount
+ * @description Verb-side mirror of getNouns-totalCount (the b2005ff fix). The
+ * verb type-scan pagination (`BaseStorage.getVerbsWithPagination`) early-terminates
+ * at `offset + limit + 1` (it peeks one extra item to compute `hasMore`), then
+ * returned `collectedVerbs.length` as `totalCount` — i.e. the PAGE size, never the
+ * dataset total. So `getVerbs({ pagination: { limit: 1 } }).totalCount` reported 1
+ * (or 2) for any non-empty brain on the unfiltered path. `totalCount` must be the
+ * authoritative O(1) verb counter (`totalVerbCount`, isNew-gated +
+ * visibility-filtered, rehydrated from `counts.json` on init).
+ */
+import { describe, it, expect } from 'vitest'
+import { mkdtempSync, rmSync } from 'fs'
+import { tmpdir } from 'os'
+import { join } from 'path'
+import { FileSystemStorage } from '../../../src/storage/adapters/fileSystemStorage.js'
+import type { VerbMetadata, HNSWVerb } from '../../../src/coreTypes.js'
+import { VerbType } from '../../../src/types/graphTypes.js'
+
+const DIM = 8
+
+/** A deterministic non-zero vector so the verb record is well-formed. */
+function vec(seed: number): number[] {
+  return Array.from({ length: DIM }, (_, i) => ((seed + i) % 7) / 7 - 0.5)
+}
+
+/** Storage shards by UUID, so ids must be 32 hex chars. */
+function uuid(i: number, salt = 0): string {
+  return (i + salt).toString(16).padStart(32, '0')
+}
+
+/**
+ * Seed `n` unique verbs. Metadata is saved BEFORE the verb record: it is where
+ * the O(1) verb counter is incremented (isNew-gated), mirroring the real
+ * relate() path.
+ */
+async function seed(storage: FileSystemStorage, n: number): Promise<void> {
+  for (let i = 0; i < n; i++) {
+    const id = uuid(i, 0x1000)
+    const sourceId = uuid(i, 0x4000)
+    const targetId = uuid(i, 0x8000)
+    await storage.saveVerbMetadata(id, {
+      verb: VerbType.RelatedTo,
+      sourceId,
+      targetId,
+      createdAt: Date.now(),
+      updatedAt: Date.now()
+    } as VerbMetadata)
+    await storage.saveVerb({
+      id,
+      vector: vec(i),
+      connections: new Map(),
+      verb: VerbType.RelatedTo,
+      sourceId,
+      targetId
+    } as HNSWVerb)
+  }
+}
+
+describe('FileSystemStorage.getVerbs totalCount (verb mirror of b2005ff)', () => {
+  it('reports the TRUE total, not the page size, for a 1-item page', async () => {
+    const dir = mkdtempSync(join(tmpdir(), 'brainy-verbtotal-'))
+    try {
+      const storage = new FileSystemStorage(dir)
+      await storage.init()
+      await seed(storage, 25)
+
+      const onePage = await storage.getVerbs({ pagination: { limit: 1 } })
+      expect(onePage.items.length).toBe(1)
+      // Before the fix this was the peeked page size (limit + 1 == 2).
+      expect(onePage.totalCount).toBe(25)
+      expect(onePage.hasMore).toBe(true)
+    } finally {
+      rmSync(dir, { recursive: true, force: true })
+    }
+  })
+
+  it('still reports the true total after a cold reopen (counts rehydrate)', async () => {
+    const dir = mkdtempSync(join(tmpdir(), 'brainy-verbtotal-reopen-'))
+    try {
+      const first = new FileSystemStorage(dir)
+      await first.init()
+      await seed(first, 25)
+      await (first as unknown as { persistCounts(): Promise<void> }).persistCounts()
+
+      const reopened = new FileSystemStorage(dir)
+      await reopened.init()
+      const page = await reopened.getVerbs({ pagination: { limit: 1 } })
+      expect(page.totalCount).toBe(25)
+    } finally {
+      rmSync(dir, { recursive: true, force: true })
+    }
+  })
+})