feat: coverage backstop — guaranteed >=90% ATS in Maximum ATS Mode (R35)

The curated denominator (R34) cleaned the score but natural weaving plateaus
(model-dependent). Per user directive (run = fit; hit 90% regardless; Max ATS =
keywords user-confirmed), added _append_skills_backstop + step 4.6 in generate_v2:
after weaving, any remaining genuine non-fit-gated curated keyword is placed in a
clean Skills "Also:" line (additive, keeps the woven bullets). Guarantees >=90% on
any role run. Honesty line held: _specialty_hit still blocks specialized/regulated;
degrees/certs/employers/seniority/dates never faked. Tests prove >=90% even when the
weave model contributes nothing. Suite green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

HISTORY.md

@@ -4,6 +4,28 @@ A running log of everything built, fixed, and changed. Most recent first.
 
 ---
 
+## 2026-06-27 — Coverage backstop: guaranteed ≥90% in Maximum ATS Mode (R35)
+
+The curated denominator (R34) made the score clean (Rank Math 156→30, real keywords)
+but coverage was still only 8/30 — the natural weave is model-dependent and plateaus.
+Per the user's explicit directive ("if I run it, it's a fit; hit 90% regardless — you
+don't know all my tasks; Maximum ATS Mode is on = treat missing keywords as
+user-confirmed"), added a deterministic guarantee:
+
+- `_append_skills_backstop()` + a `4.6` step in `generate_v2`: after natural weaving,
+  if coverage < 90, any remaining GENUINE (non-`_specialty_hit`) curated keyword is
+  placed into a clean Skills "Also:" line (additive — does NOT strip the woven
+  bullets). `judge_note` gets `+backstop`.
+- This GUARANTEES ≥90% on any role the user runs, while the honesty line still holds:
+  `_specialty_hit` blocks specialized hands-on / regulated terms, and degrees, certs,
+  employers, seniority, and dates are never faked. The Skills line carries genuine
+  JD skills the user confirmed via Maximum ATS Mode; bullets stay natural.
+- Verified: all Rank Math keywords (seo, wordpress, saas, user research, PRDs, …) are
+  ungated → placed → ≥90%. Tests: `test_backstop_places_missing_into_skills`,
+  `test_backstop_guarantees_target` (≥90% even when the weave model adds nothing).
+
+---
+
 ## 2026-06-27 — Phase 15: LLM-curated denominator + weave-to-90 + fixes (R34)
 
 A Rank Math SEO résumé (V2) still scored 30% (47/156). Diagnosis: the Phase-14 hand

src/resume_v2_natural.py

@@ -617,6 +617,38 @@ def _judge_candidates(candidates: list[dict], jd_text: str,
     return 0
 
 
+# ── Coverage backstop (R35) ──────────────────────────────────────────────────
+
+def _append_skills_backstop(src: str, keywords: list[str]) -> str:
+    """Deterministically place genuine missing keywords into a clean Skills line so
+    coverage reliably hits target. Additive only — does NOT strip the woven bullets
+    (unlike _place_sentences_structured). Used as the Maximum-ATS coverage guarantee
+    AFTER natural weaving; callers must pre-filter `_specialty_hit`/regulated terms."""
+    kws = [k.strip() for k in (keywords or []) if k and k.strip()]
+    if not kws:
+        return src
+    skills_start = src.find("\\section{SKILLS}")
+    if skills_start == -1:
+        return src
+    se = src.find("\\end{itemize}", skills_start)
+    if se == -1:
+        return src
+    close = src.rfind("}}", skills_start, se)
+    if close == -1:
+        return src
+    # Title-case-ish display, de-duplicated, capped for a clean line.
+    seen: set = set()
+    disp: list[str] = []
+    for k in kws:
+        kl = k.lower()
+        if kl not in seen:
+            seen.add(kl)
+            disp.append(k)
+    row = (" \\\\\n     \\textbf{Also}{: " + latex_escape(", ".join(disp[:24]))
+           + "} % ats-backstop\n    ")
+    return src[:close] + row + src[close:]
+
+
 # ── Coverage-aware weave pass (R32) ──────────────────────────────────────────
 
 def _coverage_weave_pass(new_src: str, decision: dict, jd_text: str, company: str,
@@ -944,6 +976,25 @@ def generate_v2(
     if _wove:
         judge_note += "+weave_pass"
 
+    # 4.6. Coverage backstop (R35): Maximum-ATS guarantee. After natural weaving, if
+    #      coverage is still below target, deterministically place any remaining
+    #      GENUINE (non-fit-gated) curated keywords into a clean Skills line. The user
+    #      enables Maximum ATS Mode = "treat missing PM/Product/AI keywords as
+    #      user-confirmed (interview-supportable)", so this is their explicit choice.
+    #      `_specialty_hit` still blocks specialized/regulated terms; honesty held.
+    try:
+        _den = decision.get("curated_keywords") or skill_relevant_filter(
+            atomic_keywords(filter_scraped_noise(
+                decision.get("expected_terms", []), jd_text, company)))
+        _cov = external_coverage(_den, latex_to_text(new_src))
+        if _cov.get("pct", 0) < 90:
+            _missing = [t for t in _cov.get("missing", []) if not _specialty_hit(t)]
+            if _missing:
+                new_src = _append_skills_backstop(new_src, _missing)
+                judge_note += "+backstop"
+    except Exception as exc:
+        log.warning("Coverage backstop failed (non-fatal): %s", exc)
+
     # 5. Compile
     comp: dict = {"compiled": False, "engine": None, "pdf_path": None}
     if compile_pdf and out_dir:

tests/test_phase14_ats.py

@@ -267,6 +267,55 @@ def test_build_report_uses_curated_denominator():
     assert report["pct"] == 67
 
 
+# ── R35: coverage backstop (Maximum-ATS guarantee) ───────────────────────────
+
+def test_backstop_places_missing_into_skills():
+    from src import resume_v2_natural as v2
+    from src.external_ats import external_coverage
+    try:
+        from src.default_resume import get_default_resume_latex
+        from src.latex_resume import latex_to_text
+    except Exception:
+        pytest.skip("resume deps unavailable")
+    src = get_default_resume_latex()
+    out = v2._append_skills_backstop(src, ["seo strategy", "wordpress ecosystem"])
+    assert "ats-backstop" in out and "Also" in out
+    text = latex_to_text(out)
+    assert external_coverage(["seo strategy", "wordpress ecosystem"], text)["pct"] == 100
+    # Additive: the original document is preserved (no content stripped).
+    assert len(out) > len(src)
+
+
+def test_backstop_guarantees_target(monkeypatch):
+    """Even when the weave model adds NOTHING relevant, the backstop guarantees >=90%
+    on a role the user runs (Maximum ATS). Real scoring; only the model is stubbed."""
+    from src import resume_v2_natural as v2
+    try:
+        from src.default_resume import get_default_resume_latex
+    except Exception:
+        pytest.skip("default resume unavailable")
+    CUR = ["alpha skill", "beta skill", "gamma skill", "delta skill", "epsilon skill",
+           "zeta skill", "eta skill", "theta skill", "iota skill", "kappa skill"]
+
+    def fake(self, cfg, system, user, max_tokens=2000):
+        s = (system or "").lower()
+        if "recruiter" in s and "screen" in s:
+            return json.dumps(CUR)
+        if "score each" in s:
+            return json.dumps({k: 80 for k in CUR})
+        if "pick the best" in s:
+            return "1"
+        # Generation / weave: generic bullets containing NONE of the curated terms.
+        return json.dumps({"psm": ["Did generic product work with no special terms."]})
+    monkeypatch.setattr(v2.LLMClient, "_call_with_cfg", fake)
+    monkeypatch.setattr(v2, "_fan_out_cfgs", lambda: [{"name": "M", "api_key": "x"}])
+    monkeypatch.setattr(v2, "_v2_model_cfg", lambda: {"name": "K", "api_key": "x"})
+    rep = v2.generate_v2(get_default_resume_latex(), "jd " + " ".join(CUR),
+                         job_title="PM", company="Co", compile_pdf=False)
+    assert rep["pct"] >= 90, f"backstop must guarantee >=90, got {rep['pct']} ({rep['missing']})"
+    assert "backstop" in rep["judge_note"]
+
+
 # ── Parseability verifier ────────────────────────────────────────────────────
 
 def test_parseability_passes_good_resume():