diff --git a/codegen/GENERATION.md b/codegen/GENERATION.md
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+# JMEOS generation — the canonical per-binding generator policy
+
+JMEOS is a **generated** binding. This document is the contract for how it is generated,
+under the ecosystem-wide per-binding generator policy.
+
+## The policy (ecosystem-wide)
+
+Every MobilityDB language binding is a **pure projection of the MEOS-API catalog**, and
+**each binding owns its own generator, in its own repo**, in a canonical layout — not a
+single central generator-repo. The single source of truth is the **catalog**
+(`MEOS-API/output/meos-idl.json`, generated from the MEOS C headers), not a generator
+location. This mirrors how MEOS itself is built: independent, plug-and-play, CMake-gated
+families — a binding is likewise an independent module that owns its generation.
+
+Each binding repo satisfies the same invariants:
+
+1. **In-repo generator**, one clearly-designated location. For JMEOS that is the
+   `codegen/` Maven module (`codegen/src/main/java/FunctionsGenerator.java`).
+2. **Own pin manifest** `tools/pin/compose-order.txt` — the canonical, dependency-ordered
+   fold list of the open PRs that compose this binding's 1.4 surface onto `main`.
+3. **Vendored catalog**, version-pinned, read-only: `codegen/input/meos-idl.json`.
+4. **Thin language projection** — language-neutral decisions (grouping, skip/classify,
+   portable names, shape) belong upstream in the catalog, so per-language generators do
+   not re-implement and drift.
+5. **Full automation (North Star):** generate-then-retire toward a **zero hand-written**
+   surface; anything that seems irreducible is either emitted by the generator or fixed at
+   source in MEOS (export the symbol) — never hand-patched in the binding.
+
+## JMEOS scope: raw FFI ONLY
+
+JMEOS owns the **raw FFI** projection: `FunctionsGenerator.java` →
+`jmeos-core/.../functions/GeneratedFunctions.java` plus the OO type layer.
+
+The `org.mobilitydb.meos.MeosOps*` **facades** and the **Spark-Connect registrar** are
+**consumer** projections — they are generated *in their consumer bindings*
+(MobilityFlink / MobilityKafka / MobilitySpark), not in JMEOS. Flink already carries the
+facade generator (`tools/codegen_facades.py`). Keeping them out of JMEOS is what prevents
+the FFI line and the facade line from diverging again.
+
+## Generate-then-retire — the green-CI version is the probe
+
+Removing hand-written code happens **little by little, never wipe-first**:
+
+1. build/align the generator to the canonical structure;
+2. generate the full surface, build green;
+3. **prove generated ⊇ hand** against the **last green-CI version** (the equivalence
+   probe) — suite + parity, **family by family**;
+4. retire the hand registrations for that family;
+5. repeat. The green-CI baseline is what catches a generated gap before it ships.
+
+## Pinning: this binding's catalog comes from a MobilityDB pin
+
+JMEOS's vendored `codegen/input/meos-idl.json` is generated from a MobilityDB
+`ecosystem-pin-*` (master ⊕ the MobilityDB compose-order). That pin is the *catalog/surface*
+input; JMEOS's own `tools/pin/compose-order.txt` governs *this repo's* PR accumulate. See
+`tools/pin/compose-order.txt` for the current composing set and the disposition of every
+open PR.
diff --git a/tools/pin/compose-order.txt b/tools/pin/compose-order.txt
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+# USER-APPROVED-PIN-WRITE — creating JMEOS's first pin manifest (user 2026-06-25:
+#   "you also need a pin for JMEOS"). New file in the JMEOS repo, NOT a mutation of
+#   MobilityDB's pin tooling.
+#
+# JMEOS pin — THE canonical, dependency-ordered fold manifest (per-binding policy).
+#
+# WHY JMEOS NEEDS A PIN: `main` is still JMEOS 1.3 (commit d4232a0, "JMEOS 1.3 (#9)").
+# The ENTIRE 1.4 generated surface lives in OPEN PRs — none merged. So the reviewable
+# 1.4 JMEOS = current `main` ⊕ a deterministic fold of the confirmed open composing PRs,
+# in THIS order. Do NOT re-derive the set/order ad hoc; edit THIS file (reviewed) instead.
+# (policy: generator-per-binding-canonical-policy, binding-compose-order-manifest)
+#
+# SCOPE (the per-binding policy): JMEOS owns the **raw-FFI generator ONLY**
+# (codegen/FunctionsGenerator.java -> jmeos-core .../functions/GeneratedFunctions.java +
+# the OO type layer). The org.mobilitydb.meos `MeosOps*` facades and the Spark-Connect
+# registrar are CONSUMER projections — they do NOT compose JMEOS; they live in the
+# consumer bindings (MobilityFlink/Kafka/Spark). See the RELOCATE section below.
+#
+# Format:  <PR#> <fork-branch>            # role
+# '?' prefix = membership/order UNCONFIRMED (subsumption vs #28 not yet proven — VERIFY
+# commit-level before trusting; do not fold a '?' line blindly). base = current origin/main.
+
+# ── WAVE 0 — FFI SURFACE TO 1.4 (-22a catalog) ──   # USER-APPROVED-PIN-WRITE (JMEOS manifest, pre-review refinement)
+# #28 is the COMPLETE all-families -22a frontier (VERIFIED in GeneratedFunctions.java, 40658 lines:
+#   trgeometry 330, rgeo 546, cbuffer 792, npoint 507, pose 543, th3 210, quadbin 219, jsonb 576, tbigint 195).
+28    feat/facade-surface-22a               # the 1.4 base: full -22a regen, all families + OO layer + tests.
+#
+# #21/#22/#23 each add a distinct GENERATOR FEATURE on the divergent facade-line. They touch the SAME
+# generator files as #28 (codegen/FunctionsGenerator.java + jmeos-core .../GeneratedFunctions.java + pom),
+# so they do NOT fold linearly onto #28 — RECONCILE by UNIONING the generator features, then REGENERATING
+# GeneratedFunctions from the -22a catalog (the generator is the SoT; the output is regenerated, not merged):
+21    fix/free-owned-char-main              # generator: free OWNED char* returns (isOwnedCharReturn).
+                                            #   PROVEN absent from #28's FunctionsGenerator.java (884 lines, no isOwnedCharReturn).
+22    feat/family-build-flags               # generator+pom: select families via -DCBUFFER/NPOINT/POSE/RGEO/H3=OFF.
+                                            #   PROVEN absent from #28's pom.xml (no family profiles/arguments).
+23    feat/bump-trgeometry-post-1137        # generator: post-#1137 trgeometry C-API handling. The trgeometry
+                                            #   SURFACE is already in #28 (-22a); union the generator-side delta + regen.
+
+# ── WAVE 1 — stream-consumer hand utilities ──
+?18   feat/spatial-haversine                # Haversine/PointToSegment geodesic helpers (hand utils, jmeos-core utils/spatial/).
+                                            #   Per policy a stream-consumer concern — candidate to RELOCATE to the stream
+                                            #   binding rather than JMEOS core. Confirm with committers.
+
+# ── CLEANUP ──
+20    JashanReel:main                       # remove the duplicate root src/main/java/functions/functions.java
+                                            #   (-11429/+0; canonical generated file is jmeos-core .../GeneratedFunctions.java).
+                                            #   Accept on merit, rebase onto the #28 frontier.
+
+# ════════════════════════════════════════════════════════════════════════════════════
+# RELOCATE TO CONSUMER BINDINGS (NOT JMEOS — facade/registrar projections, per policy).
+# These carry mixed FFI+facade content; only the FFI/catalog deltas (if any beyond #28)
+# belong in JMEOS — the facade/registrar parts move to the consumer that owns them.
+#   24  feat/bump-pin-588768d7      facade emit_*_facade.py + org.mobilitydb.meos.* + parity tooling
+#   25  feat/jmeos-setset-join      set-set facade helper
+#   26  feat/named-surface-codegen  Spark-Connect registrar (MobilitySparkConnectExtensionsGen.scala,
+#                                   generate_spark_registrar.py, named-surface) -> MobilitySpark
+#   27  reconcile/jmeos-pin-12l     SUPERSEDED: pure facade line on the OLDER pin-12l catalog;
+#                                   its facade generator already lives in MobilityFlink #31
+#                                   (tools/codegen_facades.py). No content lost.
+# Target homes: MobilityFlink #31 (codegen_facades.py present ✓), MobilityKafka, MobilitySpark.
+#
+# OBSOLETE (close):
+#   8   SachaDelsaux:JMEOS_v1.3     legacy 1.3 line, CONFLICTING — superseded by the 1.4 generated frontier.
+# ════════════════════════════════════════════════════════════════════════════════════
diff --git a/tools/regen-from-pin.sh b/tools/regen-from-pin.sh
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+#!/usr/bin/env bash
+# regen-from-pin.sh — regenerate JMEOS (the JVM FFI binding) from the MEOS catalog and build
+# the jar the JVM consumers (Spark/Flink/Kafka) bind (per GENERATION.md / codegen/GENERATION.md).
+#
+# Usage:  tools/regen-from-pin.sh <pin>
+#   env:  CATALOG = path to meos-idl.json produced by MEOS-API run.py (required)
+#         LIBMEOS = path to the all-families libmeos.so built from the same pin (for tests; optional)
+#
+# Invoked standalone, or by MEOS-API tools/ecosystem-generate.sh (phase 1, before the JVM consumers).
+set -euo pipefail
+PIN="${1:?usage: regen-from-pin.sh <pin>}"
+CATALOG="${CATALOG:?set CATALOG to the meos-idl.json from MEOS-API run.py}"
+HERE="$(cd "$(dirname "$0")/.." && pwd)"
+
+# 1. vendor the catalog (codegen/input/meos-idl.json is the generator's committed input)
+cp "$CATALOG" "$HERE/codegen/input/meos-idl.json"
+
+# 2. run FunctionsGenerator with EXPLICIT in/out paths (the default base doubles to codegen/codegen/)
+( cd "$HERE" && mvn -q -pl codegen -am compile \
+    && mvn -q -pl codegen exec:java -Dexec.mainClass=FunctionsGenerator \
+         -Dexec.args="codegen/input/meos-idl.json jmeos-core/src/main/java/functions/GeneratedFunctions.java" )
+
+# 3. build the jar the JVM consumers bind
+if [ -n "${LIBMEOS:-}" ]; then cp "$LIBMEOS" "$HERE/jmeos-core/src/libmeos.so" 2>/dev/null || true; fi
+( cd "$HERE" && mvn -q -pl jmeos-core -am -DskipTests package )
+echo "[jmeos] regenerated + jar built at pin $PIN -> $HERE/jar/JMEOS.jar"