diff --git a/.changeset/sturdy-bears-sprint.md b/.changeset/sturdy-bears-sprint.md
new file mode 100644
index 000000000..9903cd78d
--- /dev/null
+++ b/.changeset/sturdy-bears-sprint.md
@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 4318
+---
+**`state advance-plan` no longer strands you when `## Current Position` has lost its labeled plan-position lines** — the failure now returns reason `plan_position_unreadable` with the phase directory's on-disk plan/summary counts and the exact labeled lines to re-insert, instead of a bare unparseable error with no recovery path. (#4093)
diff --git a/docs/CLI-TOOLS.md b/docs/CLI-TOOLS.md
index 4fb30fd1e..25e1a0d7e 100644
--- a/docs/CLI-TOOLS.md
+++ b/docs/CLI-TOOLS.md
@@ -93,6 +93,10 @@ node gsd-tools.cjs state patch --field1 val1 --field2 val2
 
 # Increment plan counter
 node gsd-tools.cjs state advance-plan
+# When no labeled plan position can be parsed (e.g. ## Current Position drifted
+# to pure narrative prose), declines with reason "plan_position_unreadable" plus
+# the disk-derived counts and the exact labeled lines to re-insert; STATE.md is
+# left byte-identical.
 
 # Record execution metrics
 node gsd-tools.cjs state record-metric --phase N --plan M --duration Xmin [--tasks N] [--files N]
diff --git a/gsd-core/bin/lib/tdd-red-evidence.cjs b/gsd-core/bin/lib/tdd-red-evidence.cjs
new file mode 100644
index 000000000..b3644010e
--- /dev/null
+++ b/gsd-core/bin/lib/tdd-red-evidence.cjs
@@ -0,0 +1,133 @@
+"use strict";
+/**
+ * TDD RED-evidence classification (#3770).
+ *
+ * The `type: tdd` executor gate previously accepted ANY nonzero test command as
+ * RED: syntax errors, zero-test discovery, fixture crashes, parser errors, and
+ * unrelated assertions all authorized production edits (GREEN). This module
+ * defines the compact RED evidence the gate now requires — the TARGET test's
+ * identity plus a matching assertion failure — and classifies a persisted test
+ * run into exactly one verdict:
+ *
+ *   RED_EVIDENCE_OK  — nonzero exit AND the target test failed as a REAL test
+ *                      (distinctly named, TAP-reported failure). The ONLY
+ *                      verdict that may advance to GREEN.
+ *   INVALID_RED      — everything else, with a machine-readable reason:
+ *                      unexpected_green | zero_tests_discovered |
+ *                      nonzero_exit_without_test_failure |
+ *                      fixture_or_load_failure | no_target_test_failure |
+ *                      invalid_record | unreadable_record (router arm).
+ *
+ * Everything here is PURE — no fs, no spawn, no clock — so the executor can
+ * persist the record (command, exit code, failing test, expected, actual) and
+ * validate it via `gsd_run check tdd-red-evidence <record.json>`.
+ *
+ * TAP parsing reuses the proven primitives from prohibition-enforcement
+ * (`parseNodeTestSummary`, `tapFailedTestNames`) — the same contract the
+ * prohibition probe's fail-first prover already relies on (#1259).
+ */
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.classifyRedEvidence = classifyRedEvidence;
+exports.buildRedEvidenceRecord = buildRedEvidenceRecord;
+const prohibition_enforcement_cjs_1 = require("./prohibition-enforcement.cjs");
+/** Basename of a path-like string ('' for non-strings) — separators `/` and `\`. */
+function baseOf(p) {
+    return typeof p === 'string' ? (p.split(/[\\/]/).pop() ?? p) : '';
+}
+/** Coerce and validate the raw record's scalar fields. Returns null exit_code only when absent/non-numeric. */
+function readInput(input) {
+    const command = typeof input?.command === 'string' ? input.command : '';
+    const output = typeof input?.output === 'string' ? input.output : '';
+    const targetTest = typeof input?.targetTest === 'string' ? input.targetTest.trim() : '';
+    const exitCode = typeof input?.exitCode === 'number' && Number.isFinite(input.exitCode) ? input.exitCode : null;
+    if (!command || !targetTest || exitCode === null)
+        return null;
+    return { command, exitCode, output, targetTest };
+}
+/**
+ * Classify a persisted RED-phase test run. Fail-closed: malformed input, an
+ * unparseable/empty TAP summary, a file-named (load/crash) failure, or a
+ * failure that is not the target test's are all INVALID_RED — only a nonzero
+ * exit WITH the distinctly-named target test failing is RED_EVIDENCE_OK.
+ * Never throws.
+ */
+function classifyRedEvidence(input) {
+    const parsed = readInput(input);
+    if (!parsed) {
+        return {
+            verdict: 'INVALID_RED',
+            reason: 'invalid_record',
+            evidence: {
+                command: typeof input?.command === 'string' ? input.command : '',
+                exit_code: null,
+                target_test: '',
+                tests: 0,
+                pass: 0,
+                fail: 0,
+                failing_tests: [],
+            },
+        };
+    }
+    const { command, exitCode, output, targetTest } = parsed;
+    const summary = (0, prohibition_enforcement_cjs_1.parseNodeTestSummary)(output);
+    const failing = (0, prohibition_enforcement_cjs_1.tapFailedTestNames)(output);
+    const evidence = {
+        command,
+        exit_code: exitCode,
+        target_test: targetTest,
+        tests: summary.tests,
+        pass: summary.pass,
+        fail: summary.fail,
+        failing_tests: failing,
+    };
+    // Existing fail-fast rule, now machine-checked: exit 0 during RED is an
+    // unexpected GREEN — the feature may already exist or the test is wrong.
+    if (exitCode === 0) {
+        return { verdict: 'INVALID_RED', reason: 'unexpected_green', evidence };
+    }
+    // Zero-test discovery: the discovery pattern / fixture matched no tests.
+    // A run that executed nothing cannot prove anything about the behavior.
+    if (summary.tests === 0) {
+        return { verdict: 'INVALID_RED', reason: 'zero_tests_discovered', evidence };
+    }
+    // Nonzero exit but TAP reports no failing test: harness/setup/parser crash
+    // whose failure never reached a test assertion (or unparseable output).
+    if (summary.fail === 0 || failing.length === 0) {
+        return { verdict: 'INVALID_RED', reason: 'nonzero_exit_without_test_failure', evidence };
+    }
+    // Fixture/load failure: every failing entry is named like the target FILE —
+    // node reports a load-time crash (throw-on-require, syntax error, ENOENT
+    // fixture) as a file-named `not ok 1 - <file>`, never the target test.
+    const targetBase = baseOf(input?.targetFile ?? '');
+    const distinctlyNamed = failing.filter((n) => (targetBase ? baseOf(n) !== targetBase : true));
+    if (distinctlyNamed.length === 0) {
+        return { verdict: 'INVALID_RED', reason: 'fixture_or_load_failure', evidence };
+    }
+    // Unrelated failure: real tests ran and failed, but none is the target test
+    // the plan named — an unrelated assertion must not authorize GREEN.
+    if (!distinctlyNamed.includes(targetTest)) {
+        return { verdict: 'INVALID_RED', reason: 'no_target_test_failure', evidence };
+    }
+    return { verdict: 'RED_EVIDENCE_OK', reason: 'target_test_failed', evidence };
+}
+/**
+ * Project a classification into the persisted record shape — command, exit
+ * code, failing test, expected, actual, verdict, reason — so the evidence
+ * survives past the terminal and the gate can re-verify it deterministically.
+ * Pure: JSON-serializable, no timestamps (the record's mtime/commit carries time).
+ */
+function buildRedEvidenceRecord(input, result) {
+    const failingTest = result.evidence.failing_tests.find((n) => n === result.evidence.target_test) ??
+        result.evidence.failing_tests[0] ??
+        null;
+    return {
+        command: result.evidence.command,
+        exit_code: result.evidence.exit_code,
+        failing_test: failingTest,
+        target_test: result.evidence.target_test,
+        expected: typeof input?.expected === 'string' ? input.expected : null,
+        actual: typeof input?.actual === 'string' ? input.actual : null,
+        verdict: result.verdict,
+        reason: result.reason,
+    };
+}
diff --git a/src/state.cts b/src/state.cts
index 17cbb799b..b44a2ef42 100644
--- a/src/state.cts
+++ b/src/state.cts
@@ -927,11 +927,16 @@ function stateReplaceFieldWithFallback(content: string, primary: string, fallbac
  * Current Position `Phase:` line, milestone-archived layouts) keep today's
  * behavior rather than being newly refused.
  *
- * Returns `{ dir, outstanding }` where `outstanding` is empty when every plan
- * on disk is summarized (vacuously so for a zero-plan phase — #3168's
- * zero-plan-phase posture).
+ * Returns `{ dir, outstanding, planCount, summaryCount }` where `outstanding`
+ * is empty when every plan on disk is summarized (vacuously so for a zero-plan
+ * phase — #3168's zero-plan-phase posture). `planCount`/`summaryCount` are the
+ * countable disk facts behind `outstanding` (live plan files; summaries after
+ * the #3345 blocked filter) — #4093's recovery decline reports them to a
+ * caller whose STATE.md has lost its labeled plan position, so the suggested
+ * repair values are computed from the SAME set `outstanding` was, and can
+ * never disagree with a count-based decision either.
  */
-function scanOutstanding(phasesDir: string, dir: string): { dir: string; outstanding: string[] } | null {
+function scanOutstanding(phasesDir: string, dir: string): { dir: string; outstanding: string[]; planCount: number; summaryCount: number } | null {
   const phaseDirPath = path.join(phasesDir, dir);
   const scan = scanPhasePlans(phaseDirPath);
   if (scan.scope !== SCOPE.COMPLETE) return null;
@@ -942,13 +947,13 @@ function scanOutstanding(phasesDir: string, dir: string): { dir: string; outstan
     (f) => !planDependencyGraphMod.isSummaryFileBlocked(path.join(phaseDirPath, f)),
   );
   const outstanding = coreUtilsMod.findUnsummarizedPlans(scan.planFiles, countableSummaries);
-  return { dir, outstanding };
+  return { dir, outstanding, planCount: scan.planFiles.length, summaryCount: countableSummaries.length };
 }
 
 function unsummarizedPlansForPositionPhase(
   cwd: string,
   positionPhase: string,
-): { dir: string; outstanding: string[] } | null {
+): { dir: string; outstanding: string[]; planCount: number; summaryCount: number } | null {
   const phasesDir = planningPaths(cwd).phases;
   // #3185 (ADR-3180 Decision 1): "which phase directories exist" is owned by
   // listMilestonePhaseDirs — no hand-rolled readdirSync here. The owner
@@ -1003,7 +1008,12 @@ function cmdStateAdvancePlan(cwd: string, raw: boolean): void {
   // named here so the post-lock output path can report it without re-deriving.
   // Holder (not a bare let) so TypeScript's closure-unaware narrowing cannot
   // collapse the post-lock read to `never` — the callback assigns it.
-  const outstandingRef: { value: { dir: string; outstanding: string[] } | null } = { value: null };
+  const outstandingRef: { value: { dir: string; outstanding: string[]; planCount: number; summaryCount: number } | null } = { value: null };
+  // #4093: the position phase token the callback resolved (Current Position
+  // `Phase:` line first, frontmatter `current_phase` as fallback), carried out
+  // so the generic parse-failure decline can derive recovery facts from disk
+  // without re-reading STATE.md outside the lock. Same holder idiom as above.
+  const positionPhaseRef: { value: string | null } = { value: null };
   const wrote = readModifyWriteStateMd(statePath, (content) => {
     // advance-plan has no phase argument of its own — the phase it advances is
     // whatever ## Current Position names. Compare that against the milestone
@@ -1013,6 +1023,17 @@ function cmdStateAdvancePlan(cwd: string, raw: boolean): void {
     const body = stripFrontmatter(content);
     const positionScope = matchCurrentPositionSection(body) ?? body;
     const positionPhase = parseProsePhaseField(stateExtractField(positionScope, 'Phase')).phase;
+    // #4093: a Current Position section with ZERO labeled fields has no
+    // `Phase:` line either; frontmatter `current_phase` is the documented
+    // survivor of body drift (the reporter's document still carried it, and
+    // `buildStateFrontmatter` re-derives it from the body only when the body
+    // HAS the line). It feeds the recovery DECLINE only — never a write.
+    let fmPhase: string | null = null;
+    if (positionPhase === null) {
+      const fmToken = extractFrontmatter(content, statePath)['current_phase'];
+      fmPhase = typeof fmToken === 'string' && fmToken.trim() !== '' ? fmToken.trim() : null;
+    }
+    positionPhaseRef.value = positionPhase ?? fmPhase;
     if (positionPhase !== null) {
       milestoneConflict = milestoneLockMod.checkMilestonePosition(cwd, positionPhase);
       if (milestoneConflict) {
@@ -1100,7 +1121,58 @@ function cmdStateAdvancePlan(cwd: string, raw: boolean): void {
       }, raw, undefined);
       return;
     }
-    output({ error: advancePlanShapeError() }, raw, undefined);
+    // #4093: the generic terminus — no accepted labeled plan-position shape
+    // parsed anywhere in the document (the reporter's case: ## Current
+    // Position drifted to pure narrative prose with zero labeled fields).
+    // Every OTHER refusal above carries a machine-readable reason and the
+    // evidence to act on; this one stranded the caller at a bare sentence
+    // with no recovery path. Give it the same posture: a `reason` the caller
+    // can branch on, plus — when the position phase can be resolved and its
+    // directory scanned — the disk-derived facts and the exact labeled lines
+    // to re-insert. Nothing is WRITTEN: STATE.md is returned byte-identical
+    // (the callback already returned the original content for this path),
+    // so the decline is idempotent and no repair is guessed into the file —
+    // the caller (human or agent) applies the suggested lines and re-runs.
+    // Disk is the recovery source per #4067's posture; the values below are
+    // computed from the SAME `scanOutstanding` counts the plans_outstanding
+    // guard uses, so the two declines can never disagree about a phase.
+    const positionToken = positionPhaseRef.value;
+    const diskFacts = positionToken !== null
+      ? unsummarizedPlansForPositionPhase(cwd, positionToken)
+      : null;
+    if (diskFacts === null) {
+      // No resolvable phase (no Phase: line, no current_phase frontmatter, or
+      // no matching phase directory / incomplete scan): keep today's shape
+      // error, plus the reason so callers can tell this refusal from the
+      // ambiguous_* ones without string-matching the sentence.
+      output({ error: advancePlanShapeError(), reason: 'plan_position_unreadable' }, raw, undefined);
+      return;
+    }
+    const planCount = diskFacts.planCount;
+    const summarized = diskFacts.summaryCount;
+    // A summarized count below the plan count means the next plan to execute
+    // is summarized+1; an equal count means the phase is done on disk and the
+    // position line should say so (current = total; the next advance-plan run
+    // takes the #4067-guarded phase-complete branch from it). Zero plan files
+    // means disk has no opinion — suggest nothing rather than `1 of 0`.
+    const payload: Record<string, unknown> = {
+      error: advancePlanShapeError(),
+      reason: 'plan_position_unreadable',
+      phase_dir: diskFacts.dir,
+      disk: { plan_count: planCount, summarized_count: summarized },
+    };
+    if (planCount > 0) {
+      const current = summarized < planCount ? summarized + 1 : planCount;
+      payload['suggested'] = {
+        current_plan: current,
+        total_plans: planCount,
+        lines: [`Current Plan: ${current}`, `Total Plans in Phase: ${planCount}`],
+      };
+      payload['error'] =
+        `${advancePlanShapeError()} Disk for phase ${diskFacts.dir}: ${summarized} of ${planCount} plan(s) summarized. ` +
+        `Re-insert a labeled plan position at the top of ## Current Position (e.g. Current Plan: ${current} with Total Plans in Phase: ${planCount}), then re-run.`;
+    }
+    output(payload, raw, undefined);
     return;
   }
 
diff --git a/tests/lint-compiled-artifact-sync.test.cjs b/tests/lint-compiled-artifact-sync.test.cjs
index e3ef77898..0cee4336d 100644
--- a/tests/lint-compiled-artifact-sync.test.cjs
+++ b/tests/lint-compiled-artifact-sync.test.cjs
@@ -183,8 +183,20 @@ describe('fix-2657: compiled .cjs artifacts are gitignored, not tracked (ADR-457
   });
 
   test('lint-compiled-artifact-sync exits 0 with nothing left to check', () => {
+    // #4093 CI: this spawn is NOT the PROBE class the shared default below
+    // describes. The script's "nothing left to check" path still runs a FULL
+    // `tsc -p tsconfig.build.json` compile to a throwaway outDir whenever any
+    // compiled artifact remains tracked (ten are, deliberately — ADR-457's
+    // staged end state), and under CI shard load that compile can exceed the
+    // 15s probe budget, dying to a SIGTERM with empty piped stdout (observed
+    // twice on ubuntu shard 1/3). Per helpers/timeouts.cjs's own rule, a call
+    // site that genuinely differs from its class — "a real `tsc` compile" —
+    // keeps its own local constant with its own justifying comment; see
+    // tests/ensure-runtime-build.test.cjs's BUILD_TIMEOUT_MS for the other
+    // instance. 60s is that same class, sized for the cold-cache CI case.
+    const TSC_COMPILE_TIMEOUT_MS = 60000;
     const args = [path.join(REPO_ROOT, 'scripts', 'lint-compiled-artifact-sync.cjs')];
-    const result = run(process.execPath, args);
+    const result = run(process.execPath, args, { timeoutMs: TSC_COMPILE_TIMEOUT_MS });
     assert.equal(result.status, 0, describeFailure(process.execPath, args, result));
   });
 });
diff --git a/tests/state.test.cjs b/tests/state.test.cjs
index 0fb0f3808..099f9a24d 100644
--- a/tests/state.test.cjs
+++ b/tests/state.test.cjs
@@ -2096,6 +2096,156 @@ describe('cmdStateAdvancePlan (state advance-plan)', () => {
       assert.ok(updated.includes('Plan: 2 of 3'), 'Plan counter should advance to 2 of 3');
     });
   });
+
+  describe('cmdStateAdvancePlan #4093 zero-labeled-fields recovery decline', () => {
+    // The reporter's exact shape: ## Current Position has drifted to pure
+    // narrative prose — zero matches for Phase:/Plan:/Current Plan:/Total
+    // Plans in Phase: anywhere in the file, bold or plain — while frontmatter
+    // still carries current_phase and the phase directory still holds the
+    // plan/summary set that IS the position. advance-plan must not strand the
+    // caller at a bare "cannot parse" error: the decline carries a
+    // machine-readable reason plus the disk-derived facts needed to repair.
+    const narrativeFixture = [
+      '---',
+      'status: Executing',
+      'current_phase: 01',
+      'current_phase_name: Implementation',
+      'last_activity: 2026-09-01',
+      '---',
+      '',
+      '# Project State',
+      '',
+      '## Current Position',
+      '',
+      '**Phase 1 plan 2** (auth flow): EXECUTED — token round-trip verified end to end.',
+      "Follow-ups captured in plan 3's tasks.",
+      '',
+      '## Session',
+      '',
+      'Session ID: abc',
+      '',
+    ].join('\n');
+
+    const seedPhaseDir = (dir, planCount, summaryCount) => {
+      const phaseDir = path.join(tmpDir, '.planning', 'phases', dir);
+      fs.mkdirSync(phaseDir, { recursive: true });
+      for (let i = 1; i <= planCount; i++) {
+        fs.writeFileSync(path.join(phaseDir, `01-0${i}-PLAN.md`), `# plan ${i}\n`);
+      }
+      for (let i = 1; i <= summaryCount; i++) {
+        fs.writeFileSync(path.join(phaseDir, `01-0${i}-SUMMARY.md`), `# summary ${i}\n`);
+      }
+      return phaseDir;
+    };
+
+    test('#4093 declines with disk-derived repair guidance when Current Position has zero labeled fields', () => {
+      fs.writeFileSync(path.join(tmpDir, '.planning', 'STATE.md'), narrativeFixture);
+      seedPhaseDir('01-impl', 2, 1);
+
+      const result = runGsdTools('state advance-plan', tmpDir);
+      assert.ok(result.success, `Command should exit 0: ${result.error}`);
+
+      const out = JSON.parse(result.output);
+      assert.ok(typeof out.error === 'string' && /cannot read the plan position/i.test(out.error),
+        `error should still name the unreadable plan position; got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.reason, 'plan_position_unreadable',
+        `reason should be plan_position_unreadable; got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.phase_dir, '01-impl',
+        `phase_dir should name the disk phase directory; got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.disk.plan_count, 2,
+        `disk.plan_count should count the 2 plan files; got: ${JSON.stringify(out.disk)}`);
+      assert.strictEqual(out.disk.summarized_count, 1,
+        `disk.summarized_count should count the 1 summary; got: ${JSON.stringify(out.disk)}`);
+      assert.strictEqual(out.suggested.current_plan, 2,
+        `next plan after 1 summarized of 2 is 2; got: ${JSON.stringify(out.suggested)}`);
+      assert.strictEqual(out.suggested.total_plans, 2,
+        `suggested total is the on-disk plan count; got: ${JSON.stringify(out.suggested)}`);
+      assert.ok(out.suggested.lines.includes('Current Plan: 2') && out.suggested.lines.includes('Total Plans in Phase: 2'),
+        `suggested lines should name the legacy pair to re-insert; got: ${JSON.stringify(out.suggested)}`);
+
+      const after = fs.readFileSync(path.join(tmpDir, '.planning', 'STATE.md'), 'utf-8');
+      assert.strictEqual(after, narrativeFixture,
+        'a recovery decline must leave STATE.md byte-identical');
+    });
+
+    test('#4093 resolves the position phase from the Phase line when frontmatter has none', () => {
+      const noFm = [
+        '# Project State',
+        '',
+        '## Current Position',
+        '',
+        'Phase: 2 — Build out',
+        '',
+        'All narrative from here; the labeled plan lines were displaced by executor notes.',
+        '',
+      ].join('\n') + '\n';
+      fs.writeFileSync(path.join(tmpDir, '.planning', 'STATE.md'), noFm);
+      const phaseDir = path.join(tmpDir, '.planning', 'phases', '02-second');
+      fs.mkdirSync(phaseDir, { recursive: true });
+      for (let i = 1; i <= 3; i++) fs.writeFileSync(path.join(phaseDir, `02-0${i}-PLAN.md`), `# plan ${i}\n`);
+      fs.writeFileSync(path.join(phaseDir, '02-01-SUMMARY.md'), '# summary 1\n');
+
+      const result = runGsdTools('state advance-plan', tmpDir);
+      assert.ok(result.success, `Command should exit 0: ${result.error}`);
+
+      const out = JSON.parse(result.output);
+      assert.strictEqual(out.reason, 'plan_position_unreadable', `got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.phase_dir, '02-second',
+        `phase should resolve from the Phase: prose line; got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.suggested.current_plan, 2, `got: ${JSON.stringify(out.suggested)}`);
+      assert.strictEqual(out.suggested.total_plans, 3, `got: ${JSON.stringify(out.suggested)}`);
+    });
+
+    test('#4093 names the reason even when no phase can be resolved from disk or frontmatter', () => {
+      fs.writeFileSync(
+        path.join(tmpDir, '.planning', 'STATE.md'),
+        '# Project State\n\n## Current Position\n\nPure narrative, no labeled lines anywhere.\n',
+      );
+
+      const result = runGsdTools('state advance-plan', tmpDir);
+      assert.ok(result.success, `Command should exit 0: ${result.error}`);
+
+      const out = JSON.parse(result.output);
+      assert.strictEqual(out.reason, 'plan_position_unreadable', `got: ${JSON.stringify(out)}`);
+      assert.ok(/cannot read the plan position/i.test(out.error),
+        `the accepted-shape sentence must survive; got: ${out.error}`);
+      assert.strictEqual(out.phase_dir, undefined,
+        `no resolvable phase means no phase_dir; got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.disk, undefined, `no resolvable phase means no disk block`);
+    });
+
+    test('#4093 omits suggested values when the phase directory has no plan files', () => {
+      fs.writeFileSync(path.join(tmpDir, '.planning', 'STATE.md'), narrativeFixture);
+      seedPhaseDir('01-impl', 0, 0);
+
+      const result = runGsdTools('state advance-plan', tmpDir);
+      assert.ok(result.success, `Command should exit 0: ${result.error}`);
+
+      const out = JSON.parse(result.output);
+      assert.strictEqual(out.reason, 'plan_position_unreadable', `got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.phase_dir, '01-impl', `got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.disk.plan_count, 0, `got: ${JSON.stringify(out.disk)}`);
+      assert.strictEqual(out.suggested, undefined,
+        `zero plans on disk means nothing to suggest; got: ${JSON.stringify(out)}`);
+    });
+
+    test('#4093 gives the same recovery decline for a present-but-unreadable plan field', () => {
+      fs.writeFileSync(
+        path.join(tmpDir, '.planning', 'STATE.md'),
+        narrativeFixture.replace("Follow-ups captured in plan 3's tasks.", 'Plan: TBD'),
+      );
+      seedPhaseDir('01-impl', 2, 1);
+
+      const result = runGsdTools('state advance-plan', tmpDir);
+      assert.ok(result.success, `Command should exit 0: ${result.error}`);
+
+      const out = JSON.parse(result.output);
+      assert.strictEqual(out.reason, 'plan_position_unreadable', `got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.phase_dir, '01-impl', `got: ${JSON.stringify(out)}`);
+      assert.strictEqual(out.suggested.current_plan, 2, `got: ${JSON.stringify(out.suggested)}`);
+      assert.strictEqual(out.advanced, undefined, 'an unreadable position must never be advanced');
+    });
+  });
 });
 
 describe('cmdStateRecordMetric (state record-metric)', () => {