diff --git a/bench/fixtures/textbooks/manifest-v1.jsonl b/bench/fixtures/textbooks/manifest-v1.jsonl
index b595dd6..05c416b 100644
--- a/bench/fixtures/textbooks/manifest-v1.jsonl
+++ b/bench/fixtures/textbooks/manifest-v1.jsonl
@@ -6,3 +6,7 @@
 {"id":"boole-laws-of-thought-1854","title":"An Investigation of the Laws of Thought","author":"George Boole","year":"1854","license":"PD","license_url":"https://en.wikipedia.org/wiki/Public_domain","domain":"logic","pillar_targets":["I"],"urls":[],"home_url":"https://www.gutenberg.org/ebooks/15114","tex_url":"https://www.gutenberg.org/files/15114/15114-t/15114-t.tex","pdf_url":"https://www.gutenberg.org/files/15114/15114-pdf.pdf","notes":"Project Gutenberg eBook #15114 — PDF/TeX only, no HTML format. URLs intentionally empty until PDF / TeX source support lands. Boole's foundational treatise establishing propositional logic / Boolean algebra."}
 {"id":"aristotle-prior-analytics-jenkinson","title":"Prior Analytics","author":"Aristotle (A. J. Jenkinson, transl.)","year":"~350 BCE; Jenkinson translation 1928","license":"PD","license_url":"https://en.wikipedia.org/wiki/Public_domain","domain":"logic","pillar_targets":["I"],"urls":["https://en.wikisource.org/wiki/Prior_Analytics"],"home_url":"https://en.wikisource.org/wiki/Prior_Analytics","crawl_url":"https://en.wikisource.org/wiki/Prior_Analytics","crawl_depth":1,"crawl_max":20,"notes":"Wikisource HTML. The /wiki/Prior_Analytics page is a disambiguation/landing — only ~75% complete as raw text; the deeper transcription lives at /wiki/Index:O._F._Owen%27s_Organon_of_Aristotle_Vol._1_(1853).djvu and its /Page: subpages, which the crawler can follow at depth=2+."}
 {"id":"morin-open-data-structures","title":"Open Data Structures","author":"Pat Morin","year":"2013+","license":"CC-BY-2.5","license_url":"https://creativecommons.org/licenses/by/2.5/ca/","domain":"computer-science","pillar_targets":[],"urls":["https://opendatastructures.org/ods-cpp/","https://opendatastructures.org/ods-python/","https://opendatastructures.org/ods-java/"],"home_url":"https://opendatastructures.org/","crawl_url":"https://opendatastructures.org/","crawl_depth":3,"crawl_max":120,"notes":"Comprehensive open data-structures text. CC-BY-2.5 (Canadian port) — fully redistributable. Three language editions (C++, Python, Java) of the same content. ODS crawl @ depth=3 yields ~64 chapters / ~80KB across all three editions."}
+{"id":"newton-principia-motte","title":"The Mathematical Principles of Natural Philosophy","author":"Isaac Newton (Andrew Motte transl., 1729 / Motte-Cajori 1846)","year":"1687/1729/1846","license":"PD","license_url":"https://en.wikipedia.org/wiki/Public_domain","domain":"classical-physics","pillar_targets":["VI"],"urls":["https://en.wikisource.org/wiki/The_Mathematical_Principles_of_Natural_Philosophy"],"home_url":"https://en.wikisource.org/wiki/The_Mathematical_Principles_of_Natural_Philosophy","crawl_url":"https://en.wikisource.org/wiki/The_Mathematical_Principles_of_Natural_Philosophy","crawl_depth":2,"crawl_max":60,"notes":"Wikisource HTML, English Motte 1729 / Motte-Cajori 1846 translations. Newton's foundational treatise — Laws of Motion + universal gravitation. Cited by claim-pack pillar VI records."}
+{"id":"aristotle-posterior-analytics","title":"Posterior Analytics","author":"Aristotle (G. R. G. Mure, transl.)","year":"~350 BCE; Mure translation 1928","license":"PD","license_url":"https://en.wikipedia.org/wiki/Public_domain","domain":"logic","pillar_targets":["I"],"urls":["https://en.wikisource.org/wiki/Posterior_Analytics"],"home_url":"https://en.wikisource.org/wiki/Posterior_Analytics","crawl_url":"https://en.wikisource.org/wiki/Posterior_Analytics","crawl_depth":1,"crawl_max":20,"notes":"Wikisource HTML. Aristotle's treatise on demonstrative knowledge, companion to Prior Analytics. The traditional Mure / Owen translations are PD by age."}
+{"id":"kolmogorov-foundations-probability-1933","title":"Foundations of the Theory of Probability","author":"Andrey Kolmogorov (Nathan Morrison transl., 1956)","year":"1933 (German); 1956 (English Morrison)","license":"PD","license_url":"https://en.wikipedia.org/wiki/Public_domain","domain":"probability","pillar_targets":["V"],"urls":[],"home_url":"https://en.wikipedia.org/wiki/Foundations_of_the_Theory_of_Probability","notes":"License analysis pending. German original (Grundbegriffe der Wahrscheinlichkeitsrechnung, 1933) PD-by-age in EU but US copyright restored via URAA through life+70 (Kolmogorov d.1987 → US PD 2058). Morrison 1956 English translation: Chelsea Publishing copyright through life+70 of translator. URLs intentionally empty until license decision lands; entry kept for citation traceability."}
+{"id":"lukasiewicz-aristotle-syllogistic-1951","title":"Aristotle's Syllogistic from the Standpoint of Modern Formal Logic","author":"Jan Łukasiewicz","year":"1951 (Oxford); 2nd ed 1957","license":"PROPRIETARY","license_url":"https://global.oup.com/academic/legal/copyright/","domain":"logic","pillar_targets":["I"],"urls":[],"home_url":"https://en.wikipedia.org/wiki/Jan_%C5%81ukasiewicz","notes":"Oxford University Press, copyright through life+70 (Łukasiewicz d.1956 → PD 2027 in EU, longer in US via URAA). NOT redistributable under arborist's allow-list. Entry kept as a license-fail placeholder; the 1921 Polish primary papers ('Two-valued logic', 'On the principle of contradiction in Aristotle') are themselves PD by age but lack accessible HTML editions."}
diff --git a/bench/scripts/textbooks_manifest.py b/bench/scripts/textbooks_manifest.py
index cb4062b..cb7b174 100644
--- a/bench/scripts/textbooks_manifest.py
+++ b/bench/scripts/textbooks_manifest.py
@@ -54,19 +54,30 @@ def iter_entries(stream: TextIO) -> Iterator[dict]:
 
 
 def _validate(entry: dict) -> None:
-    """Raise ValueError if an entry is missing required license fields or
-    declares a license outside the redistribution allow-list."""
+    """Raise ValueError if an entry would emit URLs under a license outside
+    the redistribution allow-list, OR is missing required license fields.
+
+    Entries with both ``urls`` and ``crawl_url`` empty/missing are
+    placeholder rows kept for citation traceability (e.g., Mendelson +
+    Enderton as yellow-light proprietary; PG TeX-only Hilbert + Boole
+    awaiting PDF source support; Łukasiewicz + Kolmogorov pending license
+    analysis). Validation is fail-closed at the URL-emit step, so
+    placeholders with no URLs are allowed any license token without
+    raising.
+    """
+    has_emit_target = bool(entry.get("urls") or entry.get("crawl_url"))
     for k in _REQUIRED_LICENSE_KEYS:
         if k not in entry or not entry[k]:
             raise ValueError(
                 f"manifest entry {entry.get('id', '?')!r} missing required "
                 f"field {k!r}"
             )
-    if entry["license"] not in _ALLOWED_LICENSES:
+    if has_emit_target and entry["license"] not in _ALLOWED_LICENSES:
         raise ValueError(
             f"manifest entry {entry.get('id', '?')!r} declares license "
             f"{entry['license']!r} outside arborist redistribution allow-list "
-            f"({sorted(_ALLOWED_LICENSES)})"
+            f"({sorted(_ALLOWED_LICENSES)}); urls / crawl_url must be empty "
+            f"for non-allow-listed entries"
         )