diff --git a/gitnexus/src/core/incremental/file-hash.ts b/gitnexus/src/core/incremental/file-hash.ts
new file mode 100644
index 000000000..673e655af
--- /dev/null
+++ b/gitnexus/src/core/incremental/file-hash.ts
@@ -0,0 +1,61 @@
+/**
+ * File-content hashing — v1 "surface signature" for incremental indexing.
+ *
+ * v1 trade-off: we use SHA-256 of file content as the surface signature.
+ * This is conservative — a body-only edit (which doesn't actually change
+ * any other file's resolution) still triggers 1-hop closure expansion
+ * because the content hash differs.
+ *
+ * v2 will switch to a real surface-only signature (extracted from the
+ * post-parse graph via `extractSurfaceSignature` in `surface.ts`) so that
+ * body-only edits stay at closure size 1. The plumbing for that is in
+ * place — `surface.ts` and the closure module are signature-agnostic —
+ * but reusing the parse-worker output for one-off surface extraction
+ * requires more pipeline integration than is needed for v1.
+ */
+
+import { createHash } from 'crypto';
+import fs from 'fs/promises';
+import path from 'path';
+
+/**
+ * Compute SHA-256 hex digest of a single file. Returns null when the
+ * file can't be read (deleted between scan and hash, permission error,
+ * etc.) — caller should treat null as "no signature available, assume
+ * changed".
+ */
+export async function computeFileHash(absPath: string): Promise<string | null> {
+  try {
+    const buf = await fs.readFile(absPath);
+    return createHash('sha256').update(buf).digest('hex');
+  } catch {
+    return null;
+  }
+}
+
+/**
+ * Compute SHA-256 hashes for a list of files in `repoPath` (paths are
+ * repo-relative). Parallel batched I/O bounded at 100 concurrent reads
+ * to avoid fd exhaustion on huge repos.
+ *
+ * Returns a Map<relPath, hash>. Files that fail to read are omitted
+ * from the result (caller treats them as "no signature").
+ */
+export async function computeFileHashes(
+  repoPath: string,
+  relPaths: readonly string[],
+): Promise<Map<string, string>> {
+  const out = new Map<string, string>();
+  const BATCH = 100;
+  for (let i = 0; i < relPaths.length; i += BATCH) {
+    const batch = relPaths.slice(i, i + BATCH);
+    const results = await Promise.all(
+      batch.map(async (rel) => {
+        const hash = await computeFileHash(path.join(repoPath, rel));
+        return hash ? ([rel, hash] as const) : null;
+      }),
+    );
+    for (const r of results) if (r) out.set(r[0], r[1]);
+  }
+  return out;
+}
diff --git a/gitnexus/src/core/incremental/orchestrator.ts b/gitnexus/src/core/incremental/orchestrator.ts
new file mode 100644
index 000000000..69324da3a
--- /dev/null
+++ b/gitnexus/src/core/incremental/orchestrator.ts
@@ -0,0 +1,267 @@
+/**
+ * Incremental-indexing orchestrator helpers.
+ *
+ * High-level helpers used by `run-analyze.ts` to keep the incremental path
+ * out of the main full-rebuild orchestrator function. Each helper has one
+ * responsibility:
+ *
+ *   isIncrementalEligible(...)       — should this run go incremental?
+ *   computeIncrementalClosure(...)   — git diff → content-hash → closure
+ *   extractIncrementalSubgraph(...)  — ctx.graph → "nodes/edges to write"
+ *   commitIncrementalProgress(...)   — set the dirty flag in meta.json
+ *
+ * See docs/superpowers/specs/2026-05-10-incremental-indexing-design.md.
+ */
+
+import { execFileSync } from 'child_process';
+import type { GraphNode, GraphRelationship } from 'gitnexus-shared';
+import { createKnowledgeGraph } from '../graph/graph.js';
+import type { KnowledgeGraph } from '../graph/types.js';
+import {
+  type RepoMeta,
+  INCREMENTAL_SCHEMA_VERSION,
+  saveMeta,
+} from '../../storage/repo-manager.js';
+import { hasGitDir } from '../../storage/git.js';
+import {
+  getChangedFilesSinceCommit,
+  type ChangedFiles,
+} from './git-diff.js';
+import { computeImporterClosure } from './closure.js';
+import { computeFileHashes } from './file-hash.js';
+import { queryImporters } from '../lbug/lbug-adapter.js';
+
+/** Decision returned by isIncrementalEligible. */
+export interface IncrementalEligibility {
+  /** True iff this run should attempt the incremental path. */
+  eligible: boolean;
+  /** When `eligible === false`, a short reason for logging. */
+  reason?: string;
+  /** The previous lastCommit, when eligible. */
+  lastCommit?: string;
+}
+
+/**
+ * Decide whether a run is eligible for the incremental path.
+ *
+ * All conditions must hold:
+ *   - --force not passed
+ *   - existing meta.json present and previously a full rebuild has populated
+ *     surfaceSignatures + schemaVersion (matching CURRENT)
+ *   - repo has .git (non-git repos always do full rebuild)
+ *   - meta.lastCommit still resolvable (not rebased away)
+ *   - no incrementalInProgress flag (would force full rebuild for safety)
+ */
+export function isIncrementalEligible(
+  repoPath: string,
+  existingMeta: RepoMeta | null | undefined,
+  optionsForce: boolean | undefined,
+): IncrementalEligibility {
+  if (optionsForce) {
+    return { eligible: false, reason: '--force passed' };
+  }
+  if (!existingMeta) {
+    return { eligible: false, reason: 'no existing index' };
+  }
+  if (existingMeta.incrementalInProgress) {
+    return {
+      eligible: false,
+      reason: 'previous incremental run did not complete cleanly',
+    };
+  }
+  if (
+    existingMeta.schemaVersion === undefined ||
+    existingMeta.schemaVersion !== INCREMENTAL_SCHEMA_VERSION
+  ) {
+    return {
+      eligible: false,
+      reason: `schemaVersion mismatch (have ${existingMeta.schemaVersion}, want ${INCREMENTAL_SCHEMA_VERSION})`,
+    };
+  }
+  if (!existingMeta.surfaceSignatures || Object.keys(existingMeta.surfaceSignatures).length === 0) {
+    return {
+      eligible: false,
+      reason: 'no prior surfaceSignatures in meta.json',
+    };
+  }
+  if (!hasGitDir(repoPath)) {
+    return { eligible: false, reason: 'non-git repo' };
+  }
+  if (!existingMeta.lastCommit) {
+    return { eligible: false, reason: 'no lastCommit recorded' };
+  }
+  if (!commitExists(repoPath, existingMeta.lastCommit)) {
+    return {
+      eligible: false,
+      reason: `lastCommit ${existingMeta.lastCommit.slice(0, 7)} not in repo`,
+    };
+  }
+  return { eligible: true, lastCommit: existingMeta.lastCommit };
+}
+
+function commitExists(repoPath: string, commit: string): boolean {
+  try {
+    execFileSync('git', ['cat-file', '-e', `${commit}^{commit}`], {
+      cwd: repoPath,
+      stdio: ['ignore', 'ignore', 'ignore'],
+    });
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+export interface IncrementalSetupResult {
+  /** Files that must be re-parsed in this run. */
+  closure: Set<string>;
+  /** Files deleted on disk since lastCommit (rows must be removed from DB). */
+  deletedFiles: string[];
+  /** Per-file content hashes computed during closure expansion. */
+  newFileHashes: Map<string, string>;
+  /** ChangedFiles result for diagnostics. */
+  changes: ChangedFiles;
+}
+
+/**
+ * Compute the closure of files to re-parse for an incremental run.
+ *
+ * Algorithm:
+ *   1. git diff lastCommit HEAD ∪ git status → ChangedFiles
+ *   2. closure ← modified ∪ added
+ *   3. For each f in closure: hash(f); if hash differs from previous, query
+ *      DB importers and add them to closure. Iterate to fixpoint.
+ *
+ * Throws if `lastCommit` is gone (caller should fall back to full rebuild).
+ */
+export async function computeIncrementalClosure(
+  repoPath: string,
+  lastCommit: string,
+  prevSurfaces: Record<string, string>,
+): Promise<IncrementalSetupResult> {
+  const changes = getChangedFilesSinceCommit(repoPath, lastCommit);
+
+  const initialChangedFiles = new Set<string>([...changes.modified, ...changes.added]);
+
+  // Closure module wants generic parseFile + surfaceFor. v1 uses
+  // file-content hashes (cheap, conservative). The "ParseResult" type
+  // is just the content hash itself.
+  const { closure, newSurfaces } = await computeImporterClosure<string>({
+    initialChangedFiles,
+    prevSurfaces,
+    parseFile: async (filePath) => {
+      const hashes = await computeFileHashes(repoPath, [filePath]);
+      // Missing files (race with delete) → empty hash; counts as "changed".
+      return hashes.get(filePath) ?? '';
+    },
+    surfaceFor: (_filePath, parsed) => parsed,
+    queryImporters: async (filePath) => queryImporters(filePath),
+  });
+
+  return {
+    closure,
+    deletedFiles: changes.deleted,
+    newFileHashes: newSurfaces,
+    changes,
+  };
+}
+
+/**
+ * Persist the `incrementalInProgress` dirty flag to meta.json BEFORE any
+ * destructive DB mutation. The flag is cleared on success by overwriting
+ * meta.json with the final state. If the run crashes between, the next
+ * run sees the flag and forces a full rebuild.
+ */
+export async function commitIncrementalProgress(
+  storagePath: string,
+  existingMeta: RepoMeta,
+  closure: Set<string>,
+): Promise<void> {
+  const meta: RepoMeta = {
+    ...existingMeta,
+    incrementalInProgress: {
+      closure: [...closure],
+      startedAt: Date.now(),
+    },
+  };
+  await saveMeta(storagePath, meta);
+}
+
+/**
+ * Build a subgraph of `ctx.graph` containing ONLY the nodes/edges that
+ * need to be written to LadybugDB in incremental mode:
+ *
+ *   - All nodes whose filePath is in `closure` (newly parsed in this run).
+ *   - All graph-wide nodes (Community, Process) — they're regenerated by
+ *     the communities/processes phases on every run.
+ *   - All edges where AT LEAST ONE endpoint is in this set. Edges entirely
+ *     between hydrated unchanged-file nodes are NOT included — they're
+ *     already in the DB and re-inserting them would PK-conflict.
+ *
+ * This lets us call the existing `loadGraphToLbug` against the filtered
+ * subgraph: the COPY semantics will write only what's missing, while the
+ * unchanged-unchanged DB rows we never deleted stay intact.
+ */
+export function extractIncrementalSubgraph(
+  fullGraph: KnowledgeGraph,
+  closure: ReadonlySet<string>,
+): KnowledgeGraph {
+  const sub = createKnowledgeGraph();
+
+  const isGraphWide = (label: string): boolean => label === 'Community' || label === 'Process';
+
+  // Phase 1: nodes
+  const writableNodeIds = new Set<string>();
+  fullGraph.forEachNode((n: GraphNode) => {
+    const filePath = n.properties?.filePath as string | undefined;
+    const inClosure = filePath ? closure.has(filePath) : false;
+    if (inClosure || isGraphWide(n.label)) {
+      sub.addNode(n);
+      writableNodeIds.add(n.id);
+    }
+  });
+
+  // Phase 2: edges where AT LEAST ONE endpoint is in the writable set.
+  // Edges entirely between hydrated nodes are skipped (already in DB).
+  fullGraph.forEachRelationship((r: GraphRelationship) => {
+    if (writableNodeIds.has(r.sourceId) || writableNodeIds.has(r.targetId)) {
+      sub.addRelationship(r);
+    }
+  });
+
+  return sub;
+}
+
+/**
+ * Compute the surface signatures for every file in the repo from a graph.
+ * In v1 this is just the per-file content hash (cheap, conservative). v2
+ * will switch to true surface-only signatures derived via `surface.ts`.
+ *
+ * Used after a full rebuild to populate `meta.json.surfaceSignatures` so
+ * the next run can run incrementally.
+ */
+export async function computeAllFileSignatures(
+  repoPath: string,
+  filePaths: readonly string[],
+): Promise<Record<string, string>> {
+  const map = await computeFileHashes(repoPath, filePaths);
+  const out: Record<string, string> = {};
+  for (const [k, v] of map) out[k] = v;
+  return out;
+}
+
+/**
+ * Merge an updated set of file hashes into a previous snapshot. Used after
+ * an incremental run: `prevSurfaces` is the set in meta.json, `newSurfaces`
+ * is what we computed for closure files this run, and `deletedFiles` are
+ * files that no longer exist on disk.
+ */
+export function mergeSurfaceSignatures(
+  prevSurfaces: Record<string, string>,
+  newSurfaces: Map<string, string>,
+  deletedFiles: readonly string[],
+): Record<string, string> {
+  const merged: Record<string, string> = { ...prevSurfaces };
+  for (const f of deletedFiles) delete merged[f];
+  for (const [f, h] of newSurfaces) merged[f] = h;
+  return merged;
+}
diff --git a/gitnexus/src/core/run-analyze.ts b/gitnexus/src/core/run-analyze.ts
index 7227fd945..b15394019 100644
--- a/gitnexus/src/core/run-analyze.ts
+++ b/gitnexus/src/core/run-analyze.ts
@@ -11,6 +11,7 @@
 
 import path from 'path';
 import fs from 'fs/promises';
+import { execFileSync } from 'child_process';
 import { runPipelineFromRepo } from './ingestion/pipeline.js';
 import {
   initLbug,
@@ -20,6 +21,8 @@ import {
   executeWithReusedStatement,
   closeLbug,
   loadCachedEmbeddings,
+  deleteNodesForFile,
+  deleteAllCommunitiesAndProcesses,
 } from './lbug/lbug-adapter.js';
 import { createSearchFTSIndexes } from './search/fts-indexes.js';
 import {
@@ -29,6 +32,7 @@ import {
   ensureGitNexusIgnored,
   registerRepo,
   cleanupOldKuzuFiles,
+  INCREMENTAL_SCHEMA_VERSION,
 } from '../storage/repo-manager.js';
 import {
   getCurrentCommit,
@@ -41,6 +45,14 @@ import type { CachedEmbedding } from './embeddings/types.js';
 import { generateAIContextFiles } from '../cli/ai-context.js';
 import { EMBEDDING_TABLE_NAME } from './lbug/schema.js';
 import { STALE_HASH_SENTINEL } from './lbug/schema.js';
+import {
+  isIncrementalEligible,
+  computeIncrementalClosure,
+  commitIncrementalProgress,
+  extractIncrementalSubgraph,
+  mergeSurfaceSignatures,
+  computeAllFileSignatures,
+} from './incremental/orchestrator.js';
 
 // ---------------------------------------------------------------------------
 // Public types
@@ -180,22 +192,67 @@ export async function runFullAnalysis(
   if (existingMeta && !options.force && existingMeta.lastCommit === currentCommit) {
     // Non-git folders have currentCommit = '' — always rebuild since we can't detect changes
     if (currentCommit !== '') {
-      await ensureGitNexusIgnored(repoPath);
-      return {
-        // `resolveRepoIdentityRoot` collapses worktree roots to the
-        // canonical repo basename (#1259) but leaves arbitrary subdirs
-        // and `--skip-git` paths unchanged (#1232/#1233 intent preserved).
-        repoName:
-          options.registryName ??
-          getInferredRepoName(repoPath) ??
-          path.basename(resolveRepoIdentityRoot(repoPath)),
-        repoPath,
-        stats: existingMeta.stats ?? {},
-        alreadyUpToDate: true,
-      };
+      // For git repos, even if HEAD matches lastCommit, the working tree
+      // may have uncommitted changes. Only short-circuit when the working
+      // tree is also clean.
+      const dirty = hasDirtyTree(repoPath);
+      if (!dirty) {
+        await ensureGitNexusIgnored(repoPath);
+        return {
+          // `resolveRepoIdentityRoot` collapses worktree roots to the
+          // canonical repo basename (#1259) but leaves arbitrary subdirs
+          // and `--skip-git` paths unchanged (#1232/#1233 intent preserved).
+          repoName:
+            options.registryName ??
+            getInferredRepoName(repoPath) ??
+            path.basename(resolveRepoIdentityRoot(repoPath)),
+          repoPath,
+          stats: existingMeta.stats ?? {},
+          alreadyUpToDate: true,
+        };
+      }
     }
   }
 
+  // ── Incremental branch ─────────────────────────────────────────────
+  // Try the incremental path first. Falls through to full rebuild on:
+  //   - --force
+  //   - missing/old meta.json
+  //   - lastCommit gone (rebased)
+  //   - schemaVersion mismatch
+  //   - non-git repo
+  //   - any error during incremental setup
+  const eligibility = isIncrementalEligible(repoPath, existingMeta, options.force);
+  if (eligibility.eligible && existingMeta) {
+    try {
+      const result = await runIncrementalBranch(
+        repoPath,
+        storagePath,
+        lbugPath,
+        existingMeta,
+        currentCommit,
+        options,
+        callbacks,
+      );
+      if (result) return result;
+      // result === null → falls through to full rebuild (e.g. setup failed)
+    } catch (err) {
+      log(
+        `Incremental run failed (${(err as Error).message}); ` +
+          `next run will full-rebuild via dirty-flag.`,
+      );
+      // Re-throw — the dirty flag is set; next run forces full rebuild.
+      try {
+        await closeLbug();
+      } catch {
+        /* swallow */
+      }
+      throw err;
+    }
+  } else if (existingMeta) {
+    log(`Incremental skipped: ${eligibility.reason ?? 'unknown reason'}`);
+  }
+
   // ── Cache embeddings from existing index before rebuild ────────────
   // Four modes:
   //   --embeddings              -> load cache, restore, then generate any new ones
@@ -454,6 +511,32 @@ export async function runFullAnalysis(
     const effectiveSemanticMode =
       semanticMode ??
       (runtimeCapabilities.semanticMode === 'vector-index' ? 'vector-index' : 'exact-scan');
+
+    // Compute per-file surface signatures so the next run can be incremental.
+    // v1 uses content-hash (cheap, conservative). v2 will switch to a
+    // surface-only signature so body-only edits don't expand the closure.
+    let surfaceSignatures: Record<string, string> | undefined;
+    if (hasGitDir(repoPath)) {
+      try {
+        const allFilePaths: string[] = [];
+        pipelineResult.graph.forEachNode((n) => {
+          const fp = n.properties?.filePath as string | undefined;
+          if (fp && (n.label === 'File' || n.label === 'Folder')) {
+            // File nodes carry their own path; we want every distinct repo-relative
+            // file path that participated in indexing. Use File nodes as the
+            // authoritative source.
+            if (n.label === 'File') allFilePaths.push(fp);
+          }
+        });
+        if (allFilePaths.length > 0) {
+          surfaceSignatures = await computeAllFileSignatures(repoPath, allFilePaths);
+        }
+      } catch {
+        /* surface signatures are best-effort; their absence just means the
+         * next run will fall back to full rebuild. */
+      }
+    }
+
     const meta = {
       repoPath,
       lastCommit: currentCommit,
@@ -465,6 +548,14 @@ export async function runFullAnalysis(
       // origin remote, which is fine: paths-only repos behave as
       // before.
       remoteUrl: hasGitDir(repoPath) ? getRemoteUrl(repoPath) : undefined,
+      // Incremental-indexing fields — populated for git repos only. The
+      // next analyze run reads these to decide whether to take the
+      // incremental path. See the Incremental branch above.
+      schemaVersion: surfaceSignatures ? INCREMENTAL_SCHEMA_VERSION : undefined,
+      surfaceSignatures,
+      incrementalInProgress: undefined as
+        | { closure: string[]; startedAt: number }
+        | undefined,
       stats: {
         files: pipelineResult.totalFileCount,
         nodes: stats.nodes,
@@ -554,3 +645,242 @@ export async function runFullAnalysis(
     throw err;
   }
 }
+
+// ===========================================================================
+// Incremental analysis branch — invoked from runFullAnalysis when eligible.
+// See docs/superpowers/specs/2026-05-10-incremental-indexing-design.md.
+// ===========================================================================
+
+/**
+ * Cheap check: does the working tree have uncommitted changes? Used to
+ * decide whether the "lastCommit == HEAD" early-exit is safe to take.
+ */
+function hasDirtyTree(repoPath: string): boolean {
+  try {
+    const out = execFileSync('git', ['status', '--porcelain'], {
+      cwd: repoPath,
+      stdio: ['ignore', 'pipe', 'ignore'],
+      encoding: 'utf8',
+    });
+    return out.trim().length > 0;
+  } catch {
+    // If git status fails for any reason, conservatively assume dirty so
+    // we don't accidentally short-circuit a real change.
+    return true;
+  }
+}
+
+/**
+ * Execute the incremental branch of `runFullAnalysis`. Returns null when
+ * setup determines a full rebuild is needed instead (caller falls through).
+ *
+ * Throws if the run fails after the dirty flag is set — caller is
+ * responsible for surfacing the error; the next run will detect the dirty
+ * flag and force a full rebuild.
+ */
+async function runIncrementalBranch(
+  repoPath: string,
+  storagePath: string,
+  lbugPath: string,
+  existingMeta: import('../storage/repo-manager.js').RepoMeta,
+  currentCommit: string,
+  options: AnalyzeOptions,
+  callbacks: AnalyzeCallbacks,
+): Promise<AnalyzeResult | null> {
+  const log = (msg: string) => callbacks.onLog?.(msg);
+  const progress = (phase: string, percent: number, message: string) =>
+    callbacks.onProgress(phase, percent, message);
+
+  log(
+    `Incremental: probing for changes since ${existingMeta.lastCommit.slice(0, 7)}...`,
+  );
+
+  // 1. Compute closure (parses each file's content hash, walks DB importers).
+  let setup: Awaited<ReturnType<typeof computeIncrementalClosure>>;
+  try {
+    // Open the existing DB so closure expansion can query the IMPORTS edges.
+    await initLbug(lbugPath);
+    setup = await computeIncrementalClosure(
+      repoPath,
+      existingMeta.lastCommit,
+      existingMeta.surfaceSignatures ?? {},
+    );
+  } catch (e) {
+    try {
+      await closeLbug();
+    } catch {
+      /* swallow */
+    }
+    log(
+      `Incremental setup failed: ${(e as Error).message}. Falling back to full rebuild.`,
+    );
+    return null;
+  }
+
+  // 2. No changes? Update lastCommit and return early.
+  if (setup.closure.size === 0 && setup.deletedFiles.length === 0) {
+    log('Incremental: no file changes detected — refreshing meta only.');
+    try {
+      await closeLbug();
+    } catch {
+      /* swallow */
+    }
+    const meta: import('../storage/repo-manager.js').RepoMeta = {
+      ...existingMeta,
+      lastCommit: currentCommit,
+      indexedAt: new Date().toISOString(),
+    };
+    await saveMeta(storagePath, meta);
+    await ensureGitNexusIgnored(repoPath);
+    return {
+      repoName:
+        options.registryName ??
+        getInferredRepoName(repoPath) ??
+        path.basename(resolveRepoIdentityRoot(repoPath)),
+      repoPath,
+      stats: existingMeta.stats ?? {},
+      alreadyUpToDate: true,
+    };
+  }
+
+  log(
+    `Incremental: closure=${setup.closure.size} (changed=${setup.changes.modified.length} ` +
+      `+ added=${setup.changes.added.length} + importers=${setup.closure.size - setup.changes.modified.length - setup.changes.added.length}), ` +
+      `deleted=${setup.deletedFiles.length}`,
+  );
+
+  // 3. Mark dirty BEFORE any DB mutation. Closes lbug temporarily to
+  //    release the connection while saveMeta writes.
+  await commitIncrementalProgress(storagePath, existingMeta, setup.closure);
+
+  // 4. Delete stale rows from the DB.
+  progress('lbug', 5, 'Removing stale rows for changed files...');
+  for (const file of setup.closure) {
+    try {
+      await deleteNodesForFile(file);
+    } catch {
+      /* file may not have been indexed yet — fine */
+    }
+  }
+  for (const file of setup.deletedFiles) {
+    try {
+      await deleteNodesForFile(file);
+    } catch {
+      /* fine */
+    }
+  }
+  // Always wipe Community / Process — they're regenerated by downstream
+  // pipeline phases and must come from the merged graph for correctness
+  // (Leiden runs on the FULL hydrated + parsed graph).
+  await deleteAllCommunitiesAndProcesses();
+
+  // 5. Run the pipeline with filesToParse set so:
+  //    - hydrate phase fills ctx.graph with unchanged-file nodes from DB
+  //    - parse phase only parses closure files
+  //    - downstream phases (mro, communities, processes) see the full graph
+  const pipelineResult = await runPipelineFromRepo(
+    repoPath,
+    (p) => {
+      const phaseLabel = PHASE_LABELS[p.phase] || p.phase;
+      const scaled = 10 + Math.round(p.percent * 0.55); // 10–65%
+      const message = p.detail ? `${p.message || phaseLabel} (${p.detail})` : p.message || phaseLabel;
+      progress(p.phase, scaled, message);
+    },
+    { filesToParse: setup.closure },
+  );
+
+  // 6. Extract the subgraph that needs to be written: closure-file nodes
+  //    + graph-wide nodes + edges incident to them. Hydrated unchanged-file
+  //    nodes are NOT in this subgraph — their rows are still in DB.
+  progress('lbug', 70, 'Writing incremental updates to LadybugDB...');
+  const subgraph = extractIncrementalSubgraph(pipelineResult.graph, setup.closure);
+  await loadGraphToLbug(subgraph, repoPath, storagePath, (msg) => {
+    progress('lbug', 80, msg);
+  });
+
+  // 7. Recreate FTS indexes (cheap; full rebuild over the merged DB state).
+  progress('fts', 90, 'Refreshing search indexes...');
+  try {
+    await createSearchFTSIndexes();
+  } catch {
+    /* FTS is best-effort; log only */
+  }
+
+  // 8. Compute final stats from the live DB state.
+  const stats = await getLbugStats();
+
+  // 9. Compute new meta (merge surface signatures, clear dirty flag).
+  const mergedSurfaces = mergeSurfaceSignatures(
+    existingMeta.surfaceSignatures ?? {},
+    setup.newFileHashes,
+    setup.deletedFiles,
+  );
+
+  const newMeta: import('../storage/repo-manager.js').RepoMeta = {
+    ...existingMeta,
+    lastCommit: currentCommit,
+    indexedAt: new Date().toISOString(),
+    remoteUrl: getRemoteUrl(repoPath) ?? existingMeta.remoteUrl,
+    schemaVersion: INCREMENTAL_SCHEMA_VERSION,
+    surfaceSignatures: mergedSurfaces,
+    incrementalInProgress: undefined, // explicit clear
+    stats: {
+      ...(existingMeta.stats ?? {}),
+      files: pipelineResult.totalFileCount,
+      nodes: stats.nodes,
+      edges: stats.edges,
+      communities: pipelineResult.communityResult?.stats.totalCommunities,
+      processes: pipelineResult.processResult?.stats.totalProcesses,
+    },
+  };
+
+  // 10. Persist meta + register repo.
+  await saveMeta(storagePath, newMeta);
+  const projectName = await registerRepo(repoPath, newMeta, {
+    name: options.registryName,
+    allowDuplicateName: options.allowDuplicateName,
+  });
+
+  // 11. Best-effort AI-context regeneration so AGENTS.md/CLAUDE.md stay
+  //     in sync with the post-incremental graph state.
+  let aggregatedClusterCount = 0;
+  if (pipelineResult.communityResult?.communities) {
+    const groups = new Map<string, number>();
+    for (const c of pipelineResult.communityResult.communities) {
+      const label = c.heuristicLabel || c.label || 'Unknown';
+      groups.set(label, (groups.get(label) || 0) + c.symbolCount);
+    }
+    aggregatedClusterCount = Array.from(groups.values()).filter((cnt) => cnt >= 5).length;
+  }
+  try {
+    await generateAIContextFiles(
+      repoPath,
+      storagePath,
+      projectName,
+      {
+        files: pipelineResult.totalFileCount,
+        nodes: stats.nodes,
+        edges: stats.edges,
+        communities: pipelineResult.communityResult?.stats.totalCommunities,
+        clusters: aggregatedClusterCount,
+        processes: pipelineResult.processResult?.stats.totalProcesses,
+      },
+      undefined,
+      { skipAgentsMd: options.skipAgentsMd, noStats: options.noStats },
+    );
+  } catch {
+    /* best-effort */
+  }
+
+  await ensureGitNexusIgnored(repoPath);
+  await closeLbug();
+
+  progress('done', 100, 'Incremental complete');
+
+  return {
+    repoName: projectName,
+    repoPath,
+    stats: newMeta.stats ?? {},
+    pipelineResult,
+  };
+}
diff --git a/gitnexus/src/storage/repo-manager.ts b/gitnexus/src/storage/repo-manager.ts
index 8c0bda95f..088f3262b 100644
--- a/gitnexus/src/storage/repo-manager.ts
+++ b/gitnexus/src/storage/repo-manager.ts
@@ -71,8 +71,48 @@ export interface RepoMeta {
     processes?: number;
     embeddings?: number;
   };
+  /**
+   * Bumped whenever incremental-indexing invariants change in an
+   * incompatible way (schema bump, closure-algorithm fix, etc.).
+   * Mismatch → run-analyze forces a full rebuild.
+   * See docs/superpowers/specs/2026-05-10-incremental-indexing-design.md.
+   */
+  schemaVersion?: number;
+  /**
+   * Per-file content/surface signatures used to drive incremental closure
+   * expansion. v1: SHA-256 of file content (cheap, conservative — body-only
+   * edits trigger 1-hop closure expansion). v2 will switch to a real
+   * surface-only signature so body-only edits stay at closure size 1.
+   *
+   * Map keys are repo-relative file paths; values are hex digests. Files
+   * not in this map are treated as "no previous signature" → first-time
+   * processing.
+   */
+  surfaceSignatures?: Record<string, string>;
+  /**
+   * Crash-recovery dirty flag. Written by run-analyze BEFORE any DB
+   * mutation in an incremental run; cleared by overwrite on success. Its
+   * presence at the start of the next run forces a full rebuild — the
+   * cheapest path back to a known-good index after a crashed/cancelled
+   * incremental run. Consumed by run-analyze.ts.
+   */
+  incrementalInProgress?: {
+    closure: string[];
+    startedAt: number;
+  };
 }
 
+/**
+ * Bumped whenever incremental-indexing invariants change in an
+ * incompatible way. v1 is `1`. Increment when:
+ *   - The closure-expansion algorithm changes in a way that prior
+ *     surfaceSignatures cannot be trusted.
+ *   - The hydrate phase's DB schema assumptions change.
+ *   - The surface-signature derivation changes (so prior hashes are not
+ *     comparable to current ones).
+ */
+export const INCREMENTAL_SCHEMA_VERSION = 1;
+
 export interface IndexedRepo {
   repoPath: string;
   storagePath: string;