diff --git a/.changeset/416-active-milestone-archive-null.md b/.changeset/416-active-milestone-archive-null.md
new file mode 100644
index 000000000..bb7940716
--- /dev/null
+++ b/.changeset/416-active-milestone-archive-null.md
@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 416
+---
+`getActiveMilestoneArchiveDir` no longer falls back to the newest archive directory when the active milestone has no archive yet — returns `null` so the verifier no longer reports prior-milestone phases as "active" (eliminates W007 false positives during the flat→archive transition).
diff --git a/get-shit-done/bin/lib/verify.cjs b/get-shit-done/bin/lib/verify.cjs
index 4383e7b57..59f332a6c 100644
--- a/get-shit-done/bin/lib/verify.cjs
+++ b/get-shit-done/bin/lib/verify.cjs
@@ -441,24 +441,38 @@ function forEachArchivedPhaseToken(planBase, onPhase) {
 }
 
 function getActiveMilestoneArchiveDir(planBase) {
+  // Knuth invariant: the resolver answers exactly one question —
+  // "what archive directory holds the active milestone's phases?"
+  // Answer space: <dir> | null.
+  //
+  // When STATE.md is present and names a milestone:
+  //   - If a matching milestones/<vX.Y>-phases/ directory exists → return it.
+  //   - If no matching directory exists → return null. The active milestone
+  //     has no archive yet (phases live in flat phases/). Falling through to
+  //     an older milestone's archive is wrong and produces W007 false positives.
+  //
+  // The version-sort fallback to the newest archive fires ONLY when STATE.md is
+  // absent or unparseable — not when it cleanly names an unarchived milestone.
+
   const archiveDirs = listMilestoneArchiveDirs(planBase);
   if (archiveDirs.length === 0) return null;
 
-  // Prefer STATE.md milestone when it maps to an on-disk archive dir.
+  // STATE.md present and parseable: match wins, no-match returns null.
   try {
     const statePath = path.join(planBase, 'STATE.md');
     if (fs.existsSync(statePath)) {
       const state = fs.readFileSync(statePath, 'utf-8');
-      const m = state.match(/^\s*(?:\*\*)?milestone(?:\*\*)?:\s*([^\s\r\n#]+).*$/mi);
+      const m = state.match(/^\s*(?:\*\*)?milestone(?:\*\*)?:\s*\*{0,2}\s*([^\s*\r\n#][^\s\r\n#]*)/mi);
       if (m && m[1]) {
         const milestone = m[1].trim();
         const candidate = path.join(planBase, 'milestones', `${milestone}-phases`);
-        if (archiveDirs.includes(candidate)) return candidate;
+        // Return the matching archive, or null if the active milestone has no archive yet.
+        return archiveDirs.includes(candidate) ? candidate : null;
       }
     }
-  } catch { /* intentionally empty */ }
+  } catch { /* intentionally empty — fall through to version-sort below */ }
 
-  // Fallback when STATE.md is absent/stale: highest (most recent) archive by version-ish name.
+  // Fallback: STATE.md is absent or unparseable — highest (most recent) archive by version-ish name.
   return archiveDirs[archiveDirs.length - 1];
 }
 
diff --git a/tests/bug-416-archive-dir-null.test.cjs b/tests/bug-416-archive-dir-null.test.cjs
new file mode 100644
index 000000000..6c67caf32
--- /dev/null
+++ b/tests/bug-416-archive-dir-null.test.cjs
@@ -0,0 +1,212 @@
+'use strict';
+
+/**
+ * Regression tests for issue #416 (open-gsd/get-shit-done-redux).
+ *
+ * Bug: getActiveMilestoneArchiveDir falls back to the newest archive directory
+ * when STATE.md names a milestone that has no matching archive yet, producing
+ * W007 false positives for phases from a prior (completed) milestone.
+ *
+ * Fix: when STATE.md is present and parseable and names a milestone, but no
+ * milestones/<vX.Y>-phases/ directory matches, return null. The version-sort
+ * fallback to the newest archive fires only when STATE.md is absent or
+ * unparseable.
+ *
+ * Knuth invariant: the resolver answers one question —
+ * "what archive directory holds the active milestone's phases?"
+ * Answer space: <dir> | null.
+ */
+
+process.env.GSD_TEST_MODE = '1';
+
+const { describe, test, before, after } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+const os = require('node:os');
+
+const { runGsdTools } = require('./helpers.cjs');
+
+// ── helpers ──────────────────────────────────────────────────────────────────
+
+function mkplanning(base) {
+  const planningDir = path.join(base, '.planning');
+  const phasesDir = path.join(planningDir, 'phases');
+  fs.mkdirSync(phasesDir, { recursive: true });
+  return planningDir;
+}
+
+function writeMinimalRoadmap(planningDir, phases) {
+  // phases: array of { num, name, checked }
+  const checkboxes = phases.map(({ num, name, checked }) =>
+    `- [${checked ? 'x' : ' '}] **Phase ${num}:** ${name}`,
+  ).join('\n');
+  const headings = phases.map(({ num, name }) =>
+    `### Phase ${num}: ${name}\n**Goal:** Completed.\n`,
+  ).join('\n');
+  fs.writeFileSync(
+    path.join(planningDir, 'ROADMAP.md'),
+    `# Roadmap\n\n${checkboxes}\n\n${headings}`,
+  );
+}
+
+function writeStateMdMilestone(planningDir, milestone) {
+  fs.writeFileSync(
+    path.join(planningDir, 'STATE.md'),
+    `# State\n\n**milestone:** ${milestone}\n**Current Phase:** 23\n**Status:** In progress\n`,
+  );
+}
+
+function writeProjectMd(planningDir) {
+  fs.writeFileSync(
+    path.join(planningDir, 'PROJECT.md'),
+    '# Project\n\n## What This Is\nTest.\n\n## Core Value\nTest.\n\n## Requirements\nTest.\n',
+  );
+}
+
+function writeConfigJson(planningDir) {
+  fs.writeFileSync(
+    path.join(planningDir, 'config.json'),
+    JSON.stringify({ model_profile: 'balanced' }),
+  );
+}
+
+function mkArchivePhases(planningDir, version, phaseNums) {
+  // Creates .planning/milestones/<version>-phases/<NN>-phase-name/ dirs
+  const archiveDir = path.join(planningDir, 'milestones', `${version}-phases`);
+  for (const num of phaseNums) {
+    const padded = String(num).padStart(2, '0');
+    fs.mkdirSync(path.join(archiveDir, `${padded}-phase-${num}`), { recursive: true });
+  }
+  return archiveDir;
+}
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Case 1: STATE.md milestone: v6.0, only v5.0-phases/ on disk
+//         → resolver returns null, verifier emits zero W007 for phases 17–22
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe('bug #416 case 1: STATE.md v6.0 with only v5.0-phases/ on disk → null, no W007', () => {
+  let tmpDir;
+
+  before(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-416-c1-'));
+    const planningDir = mkplanning(tmpDir);
+    writeProjectMd(planningDir);
+    writeConfigJson(planningDir);
+
+    // Active milestone is v6.0 — no archive for it yet (phases live in flat phases/)
+    writeStateMdMilestone(planningDir, 'v6.0');
+
+    // v5.0 was the prior completed milestone; its archive exists on disk
+    mkArchivePhases(planningDir, 'v5.0', [17, 18, 19, 20, 21, 22]);
+
+    // ROADMAP reflects only v6.0 phases (v5.0 phases are in a prior milestone,
+    // not in the current roadmap section)
+    writeMinimalRoadmap(planningDir, [
+      { num: 23, name: 'New Foundation', checked: false },
+    ]);
+  });
+
+  after(() => { fs.rmSync(tmpDir, { recursive: true, force: true }); });
+
+  test('validate health emits zero W007 warnings (no prior-milestone phases surfaced)', () => {
+    const result = runGsdTools(['validate', 'health', '--json'], tmpDir);
+    assert.strictEqual(result.success, true, `validate health failed: ${result.error}`);
+    const data = JSON.parse(result.output);
+    const w007 = (data.warnings ?? []).filter((w) => w.code === 'W007');
+    assert.strictEqual(
+      w007.length,
+      0,
+      `Expected zero W007 — phases 17–22 from v5.0-phases/ must not appear as "active".\nGot: ${JSON.stringify(w007, null, 2)}`,
+    );
+  });
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Case 2: No STATE.md, multiple archives on disk → version-sort fallback
+//         returns the highest-versioned archive (existing behavior preserved)
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe('bug #416 case 2: no STATE.md + multiple archives → version-sort fallback to newest', () => {
+  let tmpDir;
+
+  before(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-416-c2-'));
+    const planningDir = mkplanning(tmpDir);
+    writeProjectMd(planningDir);
+    writeConfigJson(planningDir);
+
+    // No STATE.md — resolver must use the version-sort fallback
+    // Two archives: v4.0 and v5.0; v5.0 is newer
+    mkArchivePhases(planningDir, 'v4.0', [10, 11, 12]);
+    mkArchivePhases(planningDir, 'v5.0', [17, 18, 19]);
+
+    // ROADMAP lists v5.0 phases so W007 does not fire
+    writeMinimalRoadmap(planningDir, [
+      { num: 17, name: 'Alpha', checked: true },
+      { num: 18, name: 'Beta', checked: true },
+      { num: 19, name: 'Gamma', checked: true },
+    ]);
+  });
+
+  after(() => { fs.rmSync(tmpDir, { recursive: true, force: true }); });
+
+  test('validate health succeeds and does not emit W007 for v5.0 archive phases', () => {
+    const result = runGsdTools(['validate', 'health', '--json'], tmpDir);
+    assert.strictEqual(result.success, true, `validate health failed: ${result.error}`);
+    const data = JSON.parse(result.output);
+    const w007 = (data.warnings ?? []).filter((w) => w.code === 'W007');
+    // v5.0 phases (17–19) are in the archive returned by the fallback and
+    // in the ROADMAP, so no W007 should fire.
+    assert.strictEqual(
+      w007.length,
+      0,
+      `Expected zero W007 for v5.0 archive phases present in ROADMAP.\nGot: ${JSON.stringify(w007, null, 2)}`,
+    );
+  });
+});
+
+// ─────────────────────────────────────────────────────────────────────────────
+// Case 3: STATE.md milestone: v5.0, matching v5.0-phases/ exists → returns it
+//         (regression guard — happy path must not break)
+// ─────────────────────────────────────────────────────────────────────────────
+
+describe('bug #416 case 3: STATE.md v5.0 with matching v5.0-phases/ → returns archive dir', () => {
+  let tmpDir;
+
+  before(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-416-c3-'));
+    const planningDir = mkplanning(tmpDir);
+    writeProjectMd(planningDir);
+    writeConfigJson(planningDir);
+
+    // STATE.md names v5.0 and a matching archive exists
+    writeStateMdMilestone(planningDir, 'v5.0');
+    mkArchivePhases(planningDir, 'v5.0', [17, 18, 19, 20, 21, 22]);
+
+    // ROADMAP lists v5.0 phases so W007 does not fire
+    writeMinimalRoadmap(planningDir, [
+      { num: 17, name: 'Alpha', checked: true },
+      { num: 18, name: 'Beta', checked: true },
+      { num: 19, name: 'Gamma', checked: true },
+      { num: 20, name: 'Delta', checked: true },
+      { num: 21, name: 'Epsilon', checked: true },
+      { num: 22, name: 'Zeta', checked: true },
+    ]);
+  });
+
+  after(() => { fs.rmSync(tmpDir, { recursive: true, force: true }); });
+
+  test('validate health emits zero W007 — archive phases are in ROADMAP and active', () => {
+    const result = runGsdTools(['validate', 'health', '--json'], tmpDir);
+    assert.strictEqual(result.success, true, `validate health failed: ${result.error}`);
+    const data = JSON.parse(result.output);
+    const w007 = (data.warnings ?? []).filter((w) => w.code === 'W007');
+    assert.strictEqual(
+      w007.length,
+      0,
+      `Expected zero W007 for matching v5.0 archive with v5.0 in STATE.md.\nGot: ${JSON.stringify(w007, null, 2)}`,
+    );
+  });
+});