diff --git a/tests/e2e/conftest.py b/tests/e2e/conftest.py
index 8426e8564..3e745dc97 100644
--- a/tests/e2e/conftest.py
+++ b/tests/e2e/conftest.py
@@ -43,6 +43,28 @@ def installed_aelf() -> Sequence[str]:
     return ("uv", "run", "aelf")
 
 
+@pytest.fixture
+def installed_console_script(
+    installed_aelf: Sequence[str],
+) -> "callable[[str], Sequence[str]]":  # type: ignore[name-defined]
+    """Resolve a sibling aelfrice console script (e.g. `aelf-commit-ingest`).
+
+    Console scripts declared in pyproject.toml all land in the same bin
+    directory regardless of install method (uv-tool, pipx, venv-pip), so
+    sibling resolution from `installed_aelf` is safe. The local
+    `uv run aelf` fallback maps to `uv run <name>` for parity.
+    """
+
+    def _resolve(name: str) -> Sequence[str]:
+        head = installed_aelf[0]
+        if head == "uv" and len(installed_aelf) >= 2 and installed_aelf[1] == "run":
+            return ("uv", "run", name)
+        sibling = Path(head).with_name(name)
+        return (str(sibling),)
+
+    return _resolve
+
+
 @pytest.fixture
 def aelf_run(
     installed_aelf: Sequence[str],
diff --git a/tests/e2e/test_hook_inject_roundtrip.py b/tests/e2e/test_hook_inject_roundtrip.py
new file mode 100644
index 000000000..35b6aea7a
--- /dev/null
+++ b/tests/e2e/test_hook_inject_roundtrip.py
@@ -0,0 +1,92 @@
+"""E2E scenario #2 (#334): hook -> ingest -> rebuild -> inject roundtrip.
+
+Exercises the seam the UserPromptSubmit / PreCompact hooks travel:
+
+    pre-seeded store + recent-turn transcript
+        -> rebuild_v14 (the same code path the hook calls)
+        -> stdout context block
+        -> what the next turn would see injected.
+
+`aelf rebuild --transcript <jsonl>` is the manual entry point onto
+the hook code path (CLI docstring: "same code path as the PreCompact
+hook"), so a passing test here means the hook would also produce the
+expected block on real input. A regression on any of the three
+moving parts (transcript reader, retrieval, block renderer) drops a
+locked belief out of the rebuild output and fails this test.
+"""
+from __future__ import annotations
+
+import json
+import subprocess
+from pathlib import Path
+from typing import Callable
+
+import pytest
+
+
+pytestmark = pytest.mark.timeout(120)
+
+
+def test_locked_belief_reaches_rebuild_block(
+    aelf_run: Callable[..., subprocess.CompletedProcess[str]],
+    tmp_path: Path,
+) -> None:
+    """A locked belief related to a recent transcript turn must appear
+    in the rebuild block stdout. Failure here means the hook would
+    inject an empty / stale memory block to the next turn.
+    """
+    distinctive = (
+        "Wibble pickling requires the canonical protocol header bytes."
+    )
+    aelf_run("lock", distinctive)
+
+    # the host harness internal transcript shape: type/message/sessionId/
+    # timestamp/cwd. The rebuilder accepts this format via
+    # `--transcript` (read_recent_turns_claude_transcript).
+    transcript = tmp_path / "claude-session.jsonl"
+    turn = {
+        "type": "user",
+        "message": {
+            "role": "user",
+            "content": "How does wibble pickling handle the header?",
+        },
+        "sessionId": "e2e-hook-roundtrip",
+        "timestamp": "2026-05-02T22:00:00Z",
+        "cwd": str(tmp_path),
+    }
+    transcript.write_text(json.dumps(turn) + "\n")
+
+    result = aelf_run("rebuild", "--transcript", str(transcript))
+    assert result.returncode == 0, (
+        f"rebuild exited {result.returncode}; stderr: {result.stderr!r}"
+    )
+
+    block = result.stdout
+    # The locked belief carries the distinctive token. If retrieval +
+    # pack-to-budget are wired, "wibble" lands in the block. The exact
+    # rendering format is not coupled to here — only the content.
+    assert "wibble" in block.lower(), (
+        f"expected locked belief in rebuild block; got:\n{block!r}"
+    )
+
+
+def test_empty_store_rebuild_completes_cleanly(
+    aelf_run: Callable[..., subprocess.CompletedProcess[str]],
+    tmp_path: Path,
+) -> None:
+    """Rebuild against an empty store + empty transcript must exit 0.
+
+    Guards the no-op contract: the hook fires every turn and must
+    never wedge an empty session. If the rebuilder raised when the
+    transcript / store had no usable input, every fresh project
+    would crash on first prompt.
+    """
+    transcript = tmp_path / "empty-session.jsonl"
+    transcript.write_text("")
+    result = aelf_run(
+        "rebuild", "--transcript", str(transcript), check=False
+    )
+    assert result.returncode == 0, (
+        f"empty-input rebuild exited {result.returncode}; "
+        f"stderr: {result.stderr!r}"
+    )
diff --git a/tests/e2e/test_source_type_discrimination.py b/tests/e2e/test_source_type_discrimination.py
new file mode 100644
index 000000000..736bde412
--- /dev/null
+++ b/tests/e2e/test_source_type_discrimination.py
@@ -0,0 +1,187 @@
+"""E2E scenario #3 (#334): ingest-source discrimination across paths.
+
+Catches the #190 R1 class of regression: an INGEST_SOURCE_* constant
+is defined in `aelfrice.models`, exported, but never written to the
+store by the path that should be writing it. Unit tests are green at
+every step because each module is correct in isolation; the contract
+drift only shows up after a real cross-module ingest.
+
+The discriminating signal on a single-shot first ingest lives in
+`ingest_log.source_kind` (the v2.0 #205 source-of-truth log written
+by `record_ingest`). The corroboration table's `source_type` is the
+same wiring expressed on the re-assertion edge, but it only fires on
+content_hash hits, which a one-shot test can't reliably trigger.
+
+Each path is exercised through its real entry point and the resulting
+row in `ingest_log` is read back via stdlib `sqlite3` — no in-process
+imports of the aelfrice package, per the e2e boundary rule:
+
+    cli_remember  ->  `aelf lock <statement>`
+    filesystem    ->  `aelf ingest-transcript <jsonl>` (source_path
+                       distinguishes transcript from other filesystem
+                       ingest paths within `ingest_log`)
+    git           ->  `aelf-commit-ingest` (PostToolUse hook entry
+                       point) fed a synthetic Bash-tool payload
+
+If any of these console-script paths fails to write the expected
+`source_kind` to the store, this test fails — independent of whether
+the in-process unit tests for that module still pass.
+"""
+from __future__ import annotations
+
+import json
+import os
+import sqlite3
+import subprocess
+from pathlib import Path
+from typing import Callable, Sequence
+
+import pytest
+
+
+pytestmark = pytest.mark.timeout(120)
+
+
+def _read_ingest_source_kinds(db_path: Path) -> set[str]:
+    """Return the distinct source_kind values in `ingest_log`.
+
+    Stdlib sqlite3 read-only access; no aelfrice imports.
+    """
+    if not db_path.exists():
+        return set()
+    uri = f"file:{db_path}?mode=ro"
+    with sqlite3.connect(uri, uri=True) as conn:
+        rows = conn.execute(
+            "SELECT DISTINCT source_kind FROM ingest_log"
+        ).fetchall()
+    return {str(r[0]) for r in rows}
+
+
+def _read_transcript_source_paths(db_path: Path) -> set[str]:
+    """Distinct source_path values for filesystem-kind ingest_log rows.
+
+    Lets the test prove that `aelf ingest-transcript` lands the
+    transcript label, not just the generic filesystem source_kind.
+    """
+    if not db_path.exists():
+        return set()
+    uri = f"file:{db_path}?mode=ro"
+    with sqlite3.connect(uri, uri=True) as conn:
+        rows = conn.execute(
+            "SELECT DISTINCT source_path FROM ingest_log "
+            "WHERE source_kind = 'filesystem'"
+        ).fetchall()
+    return {str(r[0]) for r in rows if r[0] is not None}
+
+
+def test_three_paths_record_distinct_source_types(
+    aelf_run: Callable[..., subprocess.CompletedProcess[str]],
+    installed_console_script: Callable[[str], Sequence[str]],
+    ephemeral_db: Path,
+    tiny_project: Path,
+    tmp_path: Path,
+) -> None:
+    """All three first-class ingest paths must record their declared
+    `source_type` in `belief_corroborations`. Asserts the union of
+    observed source_types contains the three declared constants.
+    """
+    # Path 1: cli_remember via `aelf lock`.
+    aelf_run("lock", "Quokkas calibrate the knob carefully on Tuesdays.")
+
+    # Path 2: transcript_ingest via `aelf ingest-transcript`. A
+    # transcript-logger turns.jsonl line is the simplest accepted shape.
+    transcript = tmp_path / "turns.jsonl"
+    transcript.write_text(
+        json.dumps(
+            {
+                "role": "user",
+                "text": "The aardvark counter resets at midnight.",
+                "session_id": "e2e-source-type",
+                "ts": "2026-05-02T22:00:00Z",
+            }
+        )
+        + "\n"
+    )
+    aelf_run("ingest-transcript", str(transcript))
+
+    # Path 3: commit_ingest via the PostToolUse hook entry point. The
+    # hook reads a the host harness Bash tool payload from stdin and runs
+    # `git log -1 --format=%B <hash>` against `cwd` to fetch the body.
+    # `tiny_project` is a real git repo, so we land a fresh commit on
+    # it and shape a payload mirroring what the host harness emits.
+    # The triple extractor needs at least one (subject, relation, object)
+    # match in the message body, otherwise the hook short-circuits before
+    # opening the store. Pattern: `<NP> <verb> <NP>` with a permitted
+    # relation verb. "supports" is in the relation bank.
+    commit_msg = "feat: the yokozuna parser supports nested meridian keys"
+    git_env = {
+        **os.environ,
+        "GIT_AUTHOR_NAME": "tiny-project",
+        "GIT_AUTHOR_EMAIL": "tiny@example.invalid",
+        "GIT_COMMITTER_NAME": "tiny-project",
+        "GIT_COMMITTER_EMAIL": "tiny@example.invalid",
+    }
+    (tiny_project / "MARKER").write_text("present\n")
+    subprocess.run(  # noqa: S603, S607
+        ["git", "add", "MARKER"], cwd=tiny_project, env=git_env, check=True,
+        capture_output=True,
+    )
+    commit_proc = subprocess.run(  # noqa: S603, S607
+        ["git", "commit", "-q", "-m", commit_msg],
+        cwd=tiny_project, env=git_env, check=True, capture_output=True, text=True,
+    )
+    short_hash_proc = subprocess.run(  # noqa: S603, S607
+        ["git", "rev-parse", "--short=12", "HEAD"],
+        cwd=tiny_project, env=git_env, check=True, capture_output=True, text=True,
+    )
+    short_hash = short_hash_proc.stdout.strip()
+    # Synthesise the bracket-prefix line `[branch hash] subject` the
+    # hook expects in tool_response.stdout. Real the host harness prints
+    # this line after every successful `git commit`.
+    fake_stdout = f"[main {short_hash}] {commit_msg}\n"
+    payload = {
+        "tool_name": "Bash",
+        "tool_input": {"command": f"git commit -m {commit_msg!r}"},
+        "tool_response": {"stdout": fake_stdout, "isError": False},
+        "cwd": str(tiny_project),
+    }
+
+    hook_argv = installed_console_script("aelf-commit-ingest")
+    env = os.environ.copy()
+    env["AELFRICE_DB"] = str(ephemeral_db)
+    hook_proc = subprocess.run(  # noqa: S603
+        list(hook_argv),
+        input=json.dumps(payload),
+        env=env,
+        capture_output=True,
+        text=True,
+        timeout=60,
+        check=True,  # hook contract is exit 0 even on internal errors
+    )
+    # Hook is non-blocking by contract; surface stderr if it tracebacked.
+    assert "Traceback" not in hook_proc.stderr, hook_proc.stderr
+    # commit subprocess succeeded; sanity-check stdout had the bracket line
+    assert short_hash in commit_proc.stdout or commit_proc.returncode == 0
+
+    observed_kinds = _read_ingest_source_kinds(ephemeral_db)
+
+    # The three constants are declared in src/aelfrice/models.py:
+    # INGEST_SOURCE_CLI_REMEMBER, INGEST_SOURCE_FILESYSTEM, INGEST_SOURCE_GIT.
+    # Hard-code the literal values here so a rename-without-call-site-update
+    # on either side fails this test loudly — that is the #190 R1 bug class.
+    expected_kinds = {"cli_remember", "filesystem", "git"}
+    missing = expected_kinds - observed_kinds
+    assert not missing, (
+        f"missing source_kind rows in ingest_log: {sorted(missing)}; "
+        f"observed: {sorted(observed_kinds)}"
+    )
+
+    # Transcript ingest must additionally land its source_label so it is
+    # distinguishable from other filesystem-kind ingest paths (e.g. raw
+    # filesystem scanner). The default label from `aelf ingest-transcript`
+    # is "transcript".
+    transcript_paths = _read_transcript_source_paths(ephemeral_db)
+    assert "transcript" in transcript_paths, (
+        f"expected source_path='transcript' for filesystem-kind ingest; "
+        f"got {sorted(transcript_paths)}"
+    )