feat(spec): X11 citation-corroboration + INV-G10 amendment + Opus 4.8 halacha extraction

ספ חדש לשכבת citator פנימית — תיקוף הלכות לפי טיפול-שיפוטי מצטבר (ציטוטים נכנסים),
לצמצום היקף האישור-הידני של היו"ר:

- docs/spec/X11-citation-corroboration.md — 6 invariants (INV-COR1–COR6), כל אחד עם
  ≥3 מקורות מקצועיים (Shepard's/KeyCite, Hellyer LLJ 2018, UNC Law, NCSC/JTC, CEPEJ).
- docs/spec/00-constitution.md — תיקון מבוקר ל-INV-G10: השער מסופק ע"י טיפול-שיפוטי-מצטבר
  לתת-הקבוצה החיובית, שער-היו"ר נשאר חובה לזנב ולשלילי. + X11 באינדקס.
- Opus 4.8 @ xhigh כמודל חילוץ הלכות (config HALACHA_EXTRACT_MODEL/EFFORT, env-tunable;
  claude_session model/effort params; halacha_extractor מחווט). מבוסס A/B 2026-05-31:
  פחות חילוץ-יתר, 100% quote-verified, ביטחון מכויל.
- scripts/ab_halacha_opus48.py — harness A/B לא-הרסני להשוואת מודל/effort בחילוץ הלכות.
- .taskmaster #70 (FU-2c-b) — תיעוד dedup שפר + סריקת-קורפוס (0 stubs תקועים נותרו).

תנאי-קדם (זהות נקייה) הושלם: שפר מוזג לרשומה קנונית + סריקת 128 רשומות.
audit-findings גלויים ב-X11 §7: קישור הלכה↔ציטוט + סיווג-טיפול = greenfield, ל-implementation plan.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mcp-server/src/legal_mcp/config.py

@@ -42,6 +42,19 @@ POSTGRES_URL = os.environ.get(
 # Redis
 REDIS_URL = os.environ.get("REDIS_URL", "redis://127.0.0.1:6380/0")
 
+# Claude CLI — model + effort for halacha extraction.
+# All LLM calls go through the local `claude -p` CLI (claude_session.py).
+# By default the CLI uses the developer's session default model with no
+# explicit effort. For halacha extraction we pin Opus 4.8 @ xhigh: the
+# 2026-05-31 A/B (scripts/ab_halacha_opus48.py) showed it cuts over-extraction
+# (~124→51 on שטיין) at 100% quote-verification with honest confidence
+# calibration. Env-overridable so the model/effort can be tuned without a
+# code change (set to "" to fall back to the CLI default). Other extractors
+# (claims, metadata, block-writing, QA) keep the CLI default unless similarly
+# pinned.
+HALACHA_EXTRACT_MODEL = os.environ.get("HALACHA_EXTRACT_MODEL", "claude-opus-4-8")
+HALACHA_EXTRACT_EFFORT = os.environ.get("HALACHA_EXTRACT_EFFORT", "xhigh")
+
 # Voyage AI
 VOYAGE_API_KEY = os.environ.get("VOYAGE_API_KEY", "")
 VOYAGE_MODEL = os.environ.get("VOYAGE_MODEL", "voyage-law-2")

mcp-server/src/legal_mcp/services/claude_session.py

@@ -47,6 +47,8 @@ async def query(
     max_turns: int = 1,
     *,
     system: str | None = None,
+    model: str | None = None,
+    effort: str | None = None,
 ) -> str:
     """Send a prompt to Claude Code headless and return the text response.
 
@@ -62,6 +64,13 @@ async def query(
             CLI doesn't expose API-level caching. The parameter exists so
             extractors can structure their calls cleanly today, and to make
             a future SDK-backed path drop-in.
+        model: Optional model alias/id (e.g. ``claude-opus-4-8``). When set,
+            passed as ``--model``; otherwise the CLI's session default is
+            used. Lets quality-sensitive extractors (halacha) pin a stronger
+            model without changing the default for every caller.
+        effort: Optional effort level (``low``/``medium``/``high``/``xhigh``/
+            ``max``). When set, passed as ``--effort``. Pairs with ``model``;
+            an empty string is treated as "unset" (CLI default).
 
     Returns:
         The text response from Claude.
@@ -80,6 +89,10 @@ async def query(
         "--output-format", "json",
         "--max-turns", str(max_turns),
     ]
+    if model:
+        cmd += ["--model", model]
+    if effort:
+        cmd += ["--effort", effort]
 
     try:
         proc = await asyncio.create_subprocess_exec(
@@ -135,12 +148,15 @@ async def query_json(
     timeout: int = DEFAULT_TIMEOUT,
     *,
     system: str | None = None,
+    model: str | None = None,
+    effort: str | None = None,
 ) -> dict | list | None:
     """Send a prompt and parse the response as JSON.
 
     Uses parse_llm_json for robust parsing (handles markdown wrapping, truncation).
+    ``model``/``effort`` are forwarded to :func:`query` (see its docstring).
     """
-    raw = await query(prompt, timeout=timeout, system=system)
+    raw = await query(prompt, timeout=timeout, system=system, model=model, effort=effort)
     return parse_llm_json(raw)
 
 

mcp-server/src/legal_mcp/services/halacha_extractor.py

@@ -304,7 +304,12 @@ async def _extract_chunk(
     last_err: Exception | None = None
     for attempt in range(CHUNK_RETRY_ATTEMPTS + 1):
         try:
-            result = await claude_session.query_json(user_msg, system=base_prompt)
+            result = await claude_session.query_json(
+                user_msg,
+                system=base_prompt,
+                model=config.HALACHA_EXTRACT_MODEL or None,
+                effort=config.HALACHA_EXTRACT_EFFORT or None,
+            )
         except Exception as e:
             last_err = e
             logger.warning(