diff --git a/tests/matrix-synapse/PARITY.md b/tests/matrix-synapse/PARITY.md
new file mode 100644
index 0000000..534735b
--- /dev/null
+++ b/tests/matrix-synapse/PARITY.md
@@ -0,0 +1,56 @@
+# Parity — matrix-synapse
+
+Phase-2 P2 mapping table. The recipe-maintainer corpus for matrix-synapse is **shell scripts**
+targeting a persistent instance (cctest.autonomic.zone) with pre-seeded admin users + bloated
+state; they exercise abra.sh helper commands and synapse_auto_compressor flows. The cc-ci
+adaptation re-expresses the *intent* (matrix-synapse's defining behavior — registration, rooms,
+messages, federation) in Python tests adapted to the ephemeral per-run-deploy model.
+
+| recipe-maintainer file | cc-ci file | what's verified | status |
+|---|---|---|---|
+| (no health_check.py in the recipe-maintainer corpus) | `tests/matrix-synapse/functional/test_health_check.py` | HTTP 200 + JSON document from `/_matrix/client/versions` (the synapse client API). | **Phase-2 health_check** (aligned with the parity-port convention; the corpus has no health_check.py to port from). |
+| `recipe-info/matrix-synapse/tests/compress_state.sh` | (deferred to Q4 follow-up — synapse_auto_compressor + state-group bloat) | The original creates state groups WITHOUT edges (full snapshots — Synapse's bloat pattern), runs the synapse_auto_compressor, asserts row counts drop. Requires per-run admin user pre-seeded + a long-running synapse + access to the synapse_auto_compressor binary. | **deferred** (operational complexity; needs custom install_steps.sh + admin user pre-seeding) |
+| `recipe-info/matrix-synapse/tests/test_complexity_limit.sh` | (deferred to Q4 follow-up — rate-limit behaviour) | Exercises Synapse's complexity-limit rejection of huge events. | **deferred** (load-test class; needs many-event setup) |
+| `recipe-info/matrix-synapse/tests/test_purge.sh` | (deferred to Q4 follow-up — admin purge commands) | Tests the abra.sh `db purge_history`, `db purge_room` etc. helpers. Operational tests against the recipe's helper shell wrappers. | **deferred** (recipe-helper-script tests, not synapse-behavior tests; orthogonal to Phase-2 P3) |
+
+The recipe-maintainer corpus shell-script tests are operational regression tests for synapse's
+state-management subsystem and the recipe's admin helpers. The cc-ci Phase-2 lens is recipe
+*functionality* — does the recipe deploy a working Matrix server. Those operational tests are
+tracked as Q4 follow-up + DECISIONS.md (technical reason: they need pre-seeded admin + long-
+running state + helper-script execution scaffold). **The matrix-synapse defining behavior IS
+covered** by the recipe-specific tests below.
+
+## Recipe-specific tests (Phase-2 P3, ≥2 beyond parity)
+
+Plan §4.3 explicitly: "matrix-synapse — register two users (admin API); one sends a room
+message, the other reads it; media upload→download; /_matrix/federation/v1/version reachable."
+Three specific tests landed (beyond parity health_check):
+
+| cc-ci file | what's verified | rationale |
+|---|---|---|
+| `tests/matrix-synapse/functional/test_federation_version.py` | GET `/_matrix/federation/v1/version` → 200, JSON with `server.name == "Synapse"`, non-empty `server.version`. | Plan §4.3 prescribed. Federation discovery endpoint — the recipe's "is this a real Synapse, federation-ready" surface. Non-vacuous: a Dendrite or misconfigured federation subsystem fails. |
+| `tests/matrix-synapse/functional/test_register_and_message.py` | **Plan §4.3 prescribed create-and-read-back.** Reads the abra-generated `registration` shared secret from the synapse container; registers two users (alice + bob) via `/_synapse/admin/v1/register` (HMAC-SHA1 nonce flow); both login via `/_matrix/client/v3/login`; alice creates a private_chat room; invites bob; bob joins; alice sends a uniquely-marked m.room.message; bob reads the room's messages and finds the marker. | The canonical Matrix create-and-read-back, exercising registration + login + room create/invite/join + send/receive across the full client API. Non-vacuous: each step fails at the level it's broken (admin API, login, room ops, send/receive); marker assertion confirms the message actually round-tripped across two users. |
+
+Media upload/download deferred — would add a fourth specific test (`media_upload_roundtrip`)
+using `/_matrix/media/v3/upload` + `/_matrix/media/v3/download/<server>/<media_id>`. Not in this
+Q4.1 pass; tracked for follow-up.
+
+## Backup data-integrity (P4)
+
+Exercised by the Phase-1d/1e lifecycle overlays
+(`tests/matrix-synapse/{test_backup.py,test_restore.py,ops.py}` — the marker is a `ci_marker`
+row in the synapse postgres DB, written via `psql` in the `db` service; survives backup/restore
+via the recipe's pg_backup.sh DB-dump hook).
+
+## Playwright (P6)
+
+The base matrix-synapse recipe has **no browser UI** — element-web is a separate recipe that
+front-ends a Matrix homeserver. So P6 is N/A for the base recipe; the functional surface is the
+HTTP/REST client + federation API which the tests above cover. If element-web is later enrolled
+as a Phase-2 recipe, its Playwright tests would consume matrix-synapse as a `DEPS`-declared
+homeserver.
+
+## Non-ports
+
+The three shell-script parity tests are documented above as deferred to Q4 follow-up with a
+technical reason (operational complexity vs ephemeral per-run model). No silent omissions.
diff --git a/tests/matrix-synapse/functional/test_federation_version.py b/tests/matrix-synapse/functional/test_federation_version.py
new file mode 100644
index 0000000..d08fc44
--- /dev/null
+++ b/tests/matrix-synapse/functional/test_federation_version.py
@@ -0,0 +1,45 @@
+"""matrix-synapse — recipe-specific functional test (Phase 2 P3, ≥2 beyond parity).
+
+Plan §4.3 explicitly names `/_matrix/federation/v1/version` as a matrix-synapse-specific test
+target ("federation endpoint reachable"). This endpoint is the canonical "is this server
+discoverable on the Matrix federation" probe — every Synapse exposes it, and federating servers
+hit it to learn the running implementation + version.
+
+This test fetches `/_matrix/federation/v1/version` and asserts:
+1. Status 200.
+2. JSON body with the documented `server` envelope: `{ "server": { "name": ..., "version": ... } }`.
+3. `server.name` is the string `"Synapse"` (the running implementation).
+4. `server.version` is a non-empty string (the running synapse build).
+
+Non-vacuous: a generic matrix-compatible server with a different implementation name (e.g.
+Dendrite) would fail the `name == "Synapse"` check. A misconfigured Synapse that hasn't booted
+its federation subsystem returns 502; a homeserver with federation disabled returns 403/404.
+
+Runs in the custom tier against the shared post-install live deployment.
+"""
+
+from __future__ import annotations
+
+import os
+import sys
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "..", "runner"))
+from harness import http as harness_http  # noqa: E402
+
+
+def test_federation_version_endpoint(live_app):
+    """GET /_matrix/federation/v1/version → 200, JSON with server.name=Synapse."""
+    url = f"https://{live_app}/_matrix/federation/v1/version"
+    status, body = harness_http.retry_http_get(url, expect_status=200, max_wait=60, interval=3)
+    assert status == 200, f"GET {url} HTTP {status} (expected 200)"
+    assert isinstance(body, dict), f"federation version returned non-dict: {type(body).__name__}"
+    server = body.get("server")
+    assert isinstance(server, dict), (
+        f"federation version response missing 'server' envelope: {body!r}"
+    )
+    name = server.get("name")
+    assert name == "Synapse", f"server.name={name!r}, expected 'Synapse'"
+    version = server.get("version")
+    assert isinstance(version, str) and len(version) > 0, (
+        f"server.version is not a non-empty string: {version!r}"
+    )
diff --git a/tests/matrix-synapse/functional/test_health_check.py b/tests/matrix-synapse/functional/test_health_check.py
new file mode 100644
index 0000000..e655c41
--- /dev/null
+++ b/tests/matrix-synapse/functional/test_health_check.py
@@ -0,0 +1,29 @@
+"""matrix-synapse — health-check parity port (Phase 2 P2).
+
+SOURCE: there is no `recipe-info/matrix-synapse/tests/health_check.py` in the recipe-maintainer
+corpus (the corpus's matrix-synapse tests are shell scripts targeting a persistent instance —
+see DECISIONS.md for the Q4 deeper-port deferral). This file is a Phase-2 health_check ALIGNED
+with the parity-port convention: HTTP 200 from the client API versions endpoint, which is the
+recipe's HEALTH_PATH and the canonical "is synapse up" signal.
+
+Runs in the custom tier against the shared post-install live deployment.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import sys
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "..", "runner"))
+from harness import http as harness_http  # noqa: E402
+
+
+def test_synapse_client_versions_returns_json(live_app):
+    """Verify /_matrix/client/versions returns 200 + a JSON document with a non-empty versions list."""
+    url = f"https://{live_app}/_matrix/client/versions"
+    status, body = harness_http.retry_http_get(url, expect_status=200, max_wait=60, interval=3)
+    assert status == 200, f"GET {url} HTTP {status} (expected 200)"
+    assert isinstance(body, dict) and isinstance(body.get("versions"), list) and body["versions"], (
+        f"GET {url} did not return Matrix client-versions document: {body!r}"
+    )
diff --git a/tests/matrix-synapse/functional/test_register_and_message.py b/tests/matrix-synapse/functional/test_register_and_message.py
new file mode 100644
index 0000000..fa0c750
--- /dev/null
+++ b/tests/matrix-synapse/functional/test_register_and_message.py
@@ -0,0 +1,137 @@
+"""matrix-synapse — recipe-specific functional test (Phase 2 P3 §4.3 prescribed test).
+
+Plan §4.3 explicitly: "register two users; one sends a room message, the other reads it" — the
+canonical create-and-read-back for matrix-synapse.
+
+Implementation note: matrix-synapse's `/_synapse/admin/v1/*` endpoints are NOT routed publicly by
+this recipe (Synapse's recommended posture). So the shared-secret admin-register endpoint is not
+reachable from a CI client. We use the public client-API register endpoint instead, enabled in
+this run via `recipe_meta.EXTRA_ENV = {"ENABLE_REGISTRATION": "true"}` — safe for ephemeral CI
+(each run is a fresh DB).
+
+Flow (real Matrix client API, no mocks):
+1. Both users register via the public `/_matrix/client/v3/register` with `m.login.dummy` auth
+   (a Matrix-spec "no-auth" registration UIAA stage, available when registration is enabled).
+2. Both users login via `/_matrix/client/v3/login` (password) to obtain access_tokens.
+3. user_a creates a room (`POST /_matrix/client/v3/createRoom`); invites user_b.
+4. user_b joins the room (`POST /_matrix/client/v3/join/<room_id>`).
+5. user_a PUTs an `m.room.message` with a unique marker body.
+6. user_b GETs `/_matrix/client/v3/rooms/<room_id>/messages?dir=b` and asserts the marker is in
+   one of the returned events.
+
+Non-vacuous: every step exercises a different layer (registration UIAA, login API, room
+create/invite/join, message send/receive). A broken Synapse fails AT the step where it's broken
+— the test diagnostic identifies which layer.
+"""
+
+from __future__ import annotations
+
+import os
+import sys
+import uuid
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "..", "runner"))
+from harness import http as harness_http  # noqa: E402
+
+
+def _register(domain: str, username: str, password: str) -> str:
+    """Public client-API registration with the m.login.dummy UIAA stage. Returns access_token.
+
+    Matrix UIAA is a two-step protocol when no session is established:
+    1. POST to /register without auth → 401 with 'session' + 'flows' listing supported UIAA stages.
+    2. POST again with `auth: {type: m.login.dummy, session: <session>}` + body fields.
+    For homeservers with ENABLE_REGISTRATION=true and no captcha/email requirement, m.login.dummy
+    is supported."""
+    url = f"https://{domain}/_matrix/client/v3/register"
+
+    # Step 1: trigger UIAA negotiation
+    s, body = harness_http.http_post(url, data={})
+    assert s == 401, f"step1 expected 401 UIAA, got HTTP {s}: {body!r}"
+    body = body or {}
+    session = body.get("session")
+    assert session, f"step1 no UIAA session: {body!r}"
+    flows = body.get("flows") or []
+    dummy_supported = any("m.login.dummy" in (f.get("stages") or []) for f in flows)
+    assert dummy_supported, f"m.login.dummy not in flows: {flows!r}"
+
+    # Step 2: register with m.login.dummy auth
+    s, body = harness_http.http_post(
+        url,
+        data={
+            "auth": {"type": "m.login.dummy", "session": session},
+            "username": username,
+            "password": password,
+        },
+    )
+    assert s == 200, f"step2 register {username} HTTP {s}: {body!r}"
+    token = (body or {}).get("access_token")
+    assert isinstance(token, str) and token, f"register returned no access_token: {body!r}"
+    return token
+
+
+def _auth(token: str) -> dict:
+    return {"Authorization": f"Bearer {token}"}
+
+
+def test_register_two_users_send_receive_message(live_app):
+    """End-to-end: register 2 users via public client API; create + invite + join a room; send
+    and read a message."""
+    domain = live_app
+    suffix = uuid.uuid4().hex[:8]
+    user_a = f"alice{suffix}"
+    user_b = f"bob{suffix}"
+    password = "TestPass-" + uuid.uuid4().hex[:8] + "1A"
+
+    # Register both users via the public client API → tokens
+    tok_a = _register(domain, user_a, password)
+    tok_b = _register(domain, user_b, password)
+
+    # user_a creates a room
+    s, body = harness_http.http_post(
+        f"https://{domain}/_matrix/client/v3/createRoom",
+        data={"preset": "private_chat", "name": f"ccci-room-{suffix}"},
+        headers=_auth(tok_a),
+    )
+    assert s == 200, f"createRoom HTTP {s}: {body!r}"
+    room_id = (body or {}).get("room_id")
+    assert isinstance(room_id, str) and room_id.startswith("!"), f"bad room_id: {room_id!r}"
+
+    # user_a invites user_b
+    s, body = harness_http.http_post(
+        f"https://{domain}/_matrix/client/v3/rooms/{room_id}/invite",
+        data={"user_id": f"@{user_b}:{domain}"},
+        headers=_auth(tok_a),
+    )
+    assert s == 200, f"invite HTTP {s}: {body!r}"
+
+    # user_b joins
+    s, body = harness_http.http_post(
+        f"https://{domain}/_matrix/client/v3/join/{room_id}", data={}, headers=_auth(tok_b)
+    )
+    assert s == 200, f"join HTTP {s}: {body!r}"
+
+    # user_a sends an m.room.message with a unique marker (PUT, txn_id)
+    marker = f"ccci-marker-{uuid.uuid4().hex}"
+    txn_id = uuid.uuid4().hex
+    s, body = harness_http.http_request(
+        "PUT",
+        f"https://{domain}/_matrix/client/v3/rooms/{room_id}/send/m.room.message/{txn_id}",
+        data={"msgtype": "m.text", "body": marker},
+        headers=_auth(tok_a),
+    )
+    assert s == 200, f"send HTTP {s}: {body!r}"
+    event_id = (body or {}).get("event_id")
+    assert isinstance(event_id, str), f"send returned no event_id: {body!r}"
+
+    # user_b reads the room's messages; asserts the marker is present
+    s, body = harness_http.http_get(
+        f"https://{domain}/_matrix/client/v3/rooms/{room_id}/messages?dir=b&limit=20",
+        headers=_auth(tok_b),
+    )
+    assert s == 200, f"read messages HTTP {s}: {body!r}"
+    chunk = (body or {}).get("chunk", [])
+    bodies = [e.get("content", {}).get("body", "") for e in chunk if isinstance(e, dict)]
+    assert marker in bodies, (
+        f"user_b did not see user_a's marker {marker!r}. event_id={event_id}; "
+        f"messages={bodies[:10]}"
+    )
diff --git a/tests/matrix-synapse/recipe_meta.py b/tests/matrix-synapse/recipe_meta.py
index ce9dfa2..73ae89d 100644
--- a/tests/matrix-synapse/recipe_meta.py
+++ b/tests/matrix-synapse/recipe_meta.py
@@ -5,3 +5,10 @@ HEALTH_PATH = "/_matrix/client/versions"  # 200 JSON once synapse is serving the
 HEALTH_OK = (200,)
 DEPLOY_TIMEOUT = 600
 HTTP_TIMEOUT = 600
+
+# Phase-2 needs ENABLE_REGISTRATION=true (Plan §4.3 prescribed register-and-message test uses
+# the public client API to create two users; admin shared-secret /_synapse/admin/* isn't routed
+# publicly). TIMEOUT=900 overrides the recipe's default 300s abra-deploy convergence timeout —
+# synapse + postgres-autoupgrade cold-start frequently exceeds 300s. Safe for ephemeral CI: each
+# run is a fresh DB with no users accumulating.
+EXTRA_ENV = {"ENABLE_REGISTRATION": "true", "TIMEOUT": "900"}