phase: 102_extensionless_filenames

All verification complete — every gate green, no defects found in previously completed work.

**Phase 102 final verification pass — report**

Verified (all three task files present in `complete/`; working-tree implementation matches D1–D5 design):
- `match_extension` choke point in `app/rag/importer.py` (walk + `formats` counter), `doc_format` name-token badge in `app/api/docs.py`, config/`.env.example` docs, fixture `tests/fixtures/extensionless_kb/`, integration + E2E suites — all present and correct
- Completion criteria: end-to-end sync (✓ integration + E2E), case matrix incl. `mydockerfile`/`Dockerfile.dev`/`.dockerfile` exclusions (✓ unit), `formats=dockerfile:1` not `unknown` (✓ log-line assertion), badge `dockerfile`/`containerfile` + `text` fallback + suffixed unchanged (✓ unit/integration/E2E), prune-on-token-removal (✓ `pruned==2`), suffixed-path rule byte-identical (✓ single-line swap, existing cases untouched)

Test / lint results (exact commands):
- `uv run pytest --cov=app --cov-report=term-missing` → 2084 passed, **99%** coverage (>90% gate)
- `uv run pytest tests/e2e/test_extensionless_import.py -v --no-cov` → 2 passed, isolated, DB up
- Regressions isolated: `test_import_documents` 3✓, `test_import_extensions_env` 2✓, `test_quadlet_jinja_import` 4✓, `test_document_viewer` 7✓, `test_kb_tree` 8✓
- `uv run ruff check .` → clean; `uv run pyright` → 0 errors, 0 warnings

Notable: commit intentionally not made (harness commits the phase); 102's task files already sit in `complete/`, overview stays in `todo/` for the harness.
Next pending phases: 98, 99, 103, 104, 105 (numeric next after 102: `103_suggestions_session_openers`).

tests/unit/test_document_viewer.py

@@ -2,7 +2,9 @@
 
 Python side:
 * ``doc_format`` — format from the path suffix (incl. ``.markdown`` and the
-  no-suffix fallback);
+  no-suffix fallback) + the phase-102 extensionless name-token rule
+  (``Dockerfile`` → ``dockerfile`` with a configured token, suffixes still
+  unconditional, no-arg calls byte-identical to the suffix-only rule);
 * the content endpoint's 200/404 mapping — tested WITHOUT a database by
   stubbing the session via FastAPI's dependency override (unknown pairs and
   traversal-style paths map to 404 ``{detail: "document not found"}``;
@@ -74,6 +76,43 @@ def test_doc_format_from_suffix(path: str, expected: str) -> None:
     assert doc_format(path) == expected
 
 
+def test_doc_format_no_args_extensionless_falls_back_to_text() -> None:
+    """The no-arg contract: default ``extensions=frozenset()`` keeps the
+    pre-phase-102 result for every path — an extensionless name that LOOKS
+    like a configured token still badges ``text`` without the token set."""
+    assert doc_format("Dockerfile") == "text"
+    assert doc_format("README") == "text"
+
+
+#: A token set in the dotted form ``import_extension_set`` passes it.
+_TOKEN_EXTS = frozenset({".md", ".dev", ".dockerfile", ".containerfile"})
+
+
+@pytest.mark.parametrize(
+    ("path", "extensions", "expected"),
+    [
+        # Name-token branch (phase 102): suffix-less name in the set.
+        ("services/api/Dockerfile", _TOKEN_EXTS, "dockerfile"),
+        ("DOCKERFILE", _TOKEN_EXTS, "dockerfile"),  # case-insensitive name
+        ("Containerfile", _TOKEN_EXTS, "containerfile"),
+        # Suffix precedence: display never depends on the import list.
+        ("Dockerfile.dev", _TOKEN_EXTS, "dev"),  # suffixed → its suffix rules
+        ("readme.rst", _TOKEN_EXTS, "rst"),  # out-of-scope suffix still badges
+        ("notes/README.dev", _TOKEN_EXTS, "dev"),
+        ("dockerfile.bak", _TOKEN_EXTS, "bak"),  # lookalike → suffix, not name
+        ("kubernetes.md", frozenset(), "md"),  # empty set: suffix unconditional
+        # Extensionless names NOT in the set fall back to text — exact
+        # name only, no partial names.
+        ("README", _TOKEN_EXTS, "text"),
+        ("mydockerfile", _TOKEN_EXTS, "text"),
+    ],
+)
+def test_doc_format_with_token_set(
+    path: str, extensions: frozenset[str], expected: str
+) -> None:
+    assert doc_format(path, extensions) == expected
+
+
 # ---------------------------------------------------------------------------
 # Content endpoint mapping — stubbed session, no database required
 # ---------------------------------------------------------------------------