diff --git a/src/parser.ts b/src/parser.ts
index 24e16290..32988940 100644
--- a/src/parser.ts
+++ b/src/parser.ts
@@ -5491,7 +5491,24 @@ async function runParseInner(
   // it keeps the normal stamp.
   const deferredForFirstPaint = firstPaintDeferredThisRun > 0
   const wasComplete = isCacheComplete(diskCache)
-  if (!readOnly && !wasComplete && !deferredForFirstPaint) diskCache.complete = true
+  // A provider-scoped run walks only its own provider's sessions, so it never
+  // saw whatever the providers it skipped hold on disk. Stamping the WHOLE
+  // cache complete off that partial view writes a wrong "done" to disk (#912):
+  // per the marker's own contract above, a complete cache stops being re-read
+  // as cold, so the unscanned providers are not revisited and the gap stops
+  // looking like a gap. The guard is conditioned on real on-disk data, not on
+  // scoping alone: when every provider the run skipped has NO discoverable
+  // sessions, the scoped run really did see the whole corpus (a claude-only
+  // machine, and exactly what the warm-refresh snapshot tests rely on), so the
+  // stamp is correct and stands. Discovery here is a bounded directory walk,
+  // not a parse — the scoping win (skipping the other providers' PARSE) holds.
+  const scopedRun = !!providerFilter && providerFilter !== 'all'
+  let skippedProviderHasSessions = false
+  if (scopedRun && !readOnly && !wasComplete && !deferredForFirstPaint) {
+    const corpusSources = await discoverAllSessions()
+    skippedProviderHasSessions = corpusSources.some(s => s.provider !== providerFilter)
+  }
+  if (!readOnly && !wasComplete && !deferredForFirstPaint && !skippedProviderHasSessions) diskCache.complete = true
   if (!readOnly && (isCacheDirty(diskCache) || (!wasComplete && !deferredForFirstPaint))) {
     try {
       const published = await saveCache(diskCache, refreshLock?.verifyStillOwner)
diff --git a/tests/scoped-run-completeness.test.ts b/tests/scoped-run-completeness.test.ts
new file mode 100644
index 00000000..68d30850
--- /dev/null
+++ b/tests/scoped-run-completeness.test.ts
@@ -0,0 +1,83 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest'
+import { mkdtemp, mkdir, writeFile, rm } from 'fs/promises'
+import { join } from 'path'
+import { tmpdir } from 'os'
+
+import { parseAllSessions, clearSessionCache } from '../src/parser.js'
+import { readCacheOnDisk } from './fixtures/session-cache-io.js'
+
+let tmpDir: string
+let savedCodexHome: string | undefined
+
+beforeEach(async () => {
+  clearSessionCache()
+  tmpDir = await mkdtemp(join(tmpdir(), 'scoped-complete-'))
+  process.env['CLAUDE_CONFIG_DIR'] = tmpDir
+  process.env['CODEBURN_CACHE_DIR'] = join(tmpDir, 'cache')
+  process.env['CODEBURN_DESKTOP_SESSIONS_DIR'] = join(tmpDir, 'desktop-sessions')
+  // Hermetic: Codex discovery defaults to CODEX_HOME / ~/.codex, so without this
+  // the scoped 'codex' run below reads the developer's real local corpus. Point it
+  // at an empty temp root and restore in teardown.
+  savedCodexHome = process.env['CODEX_HOME']
+  process.env['CODEX_HOME'] = join(tmpDir, 'codex-home')
+  await mkdir(join(tmpDir, 'codex-home', 'sessions'), { recursive: true })
+})
+
+afterEach(async () => {
+  clearSessionCache()
+  if (savedCodexHome === undefined) delete process.env['CODEX_HOME']
+  else process.env['CODEX_HOME'] = savedCodexHome
+  await rm(tmpDir, { recursive: true, force: true })
+})
+
+async function writeClaudeSession(): Promise<void> {
+  const dir = join(tmpDir, 'projects', 'proj')
+  await mkdir(dir, { recursive: true })
+  await writeFile(join(dir, 'sess.jsonl'), JSON.stringify({
+    type: 'assistant',
+    sessionId: 'sess',
+    timestamp: '2026-05-15T10:00:00Z',
+    cwd: '/tmp/proj',
+    message: {
+      id: 'msg-1', type: 'message', role: 'assistant', model: 'claude-sonnet-4-5',
+      content: [], usage: { input_tokens: 100, output_tokens: 50 },
+    },
+  }) + '\n')
+}
+
+describe('provider-scoped run and the whole-cache completeness marker', () => {
+  // Regression for #912: the stamp now learns about scope. A run scoped to one provider
+  // must not mark the whole cache complete while a provider it skipped still has sessions
+  // on disk it never scanned.
+  it('does not stamp the cache complete when providers were left out of scope', async () => {
+    await writeClaudeSession()
+
+    // Scoped to 'codex': discovery is filtered and the cached-provider loop skips every
+    // other name, so the claude session on disk is never read by this run.
+    await parseAllSessions(undefined, 'codex')
+
+    const raw = await readCacheOnDisk()
+
+    // Premise: claude really was left unscanned. If this fails the scoped run read it
+    // anyway and the rest proves nothing.
+    expect(Object.keys(raw?.providers?.claude?.files ?? {}).length).toBe(0)
+
+    // The guard: the stamp at the end of runParseInner refuses to mark the whole cache
+    // complete when a skipped provider (claude here) still has discoverable sessions.
+    expect(raw?.complete ?? false).toBe(false)
+  })
+
+  it('a subsequent full run repairs the cache — the mislabel is transient, not persistent', async () => {
+    // Honouring the maintainer review: an ordinary all-provider refresh rediscovers the
+    // omitted provider, so the wrong flag does not strand it forever. Pinning the bound
+    // keeps the claim accurate.
+    await writeClaudeSession()
+
+    await parseAllSessions(undefined, 'codex')      // scoped: claude unscanned
+    clearSessionCache()
+    await parseAllSessions()                         // full refresh: claude rediscovered
+
+    const raw = await readCacheOnDisk()
+    expect(Object.keys(raw?.providers?.claude?.files ?? {}).length).toBeGreaterThan(0)
+  })
+})