diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3f30449..7f72bae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,14 @@ callers).
 
 ## [Unreleased]
 
+### Fixed
+
+- **`enrich_from_probe` now refreshes `tech_string`** after filling
+  `quality` / `source` / `codec`. Previously the field stayed at its
+  parser-time value, so filename builders saw stale tech tokens even
+  after a successful probe. New `TestTechString` class in
+  `tests/application/test_enrich_from_probe.py` locks the behavior.
+
 ### Added
 
 - **`inspect_release` orchestrator + `InspectedResult` VO**
diff --git a/alfred/application/filesystem/enrich_from_probe.py b/alfred/application/filesystem/enrich_from_probe.py
index 5aba9ee..dd66400 100644
--- a/alfred/application/filesystem/enrich_from_probe.py
+++ b/alfred/application/filesystem/enrich_from_probe.py
@@ -80,3 +80,10 @@ def enrich_from_probe(parsed: ParsedRelease, info: MediaInfo) -> None:
         for lang in info.audio_languages:
             if lang.lower() != "und" and lang.upper() not in existing:
                 parsed.languages.append(lang)
+
+    # Re-derive tech_string so filename builders see the enriched
+    # quality/source/codec. Built the same way as in the parser pipeline:
+    # the non-None parts joined by dots, in order.
+    parsed.tech_string = ".".join(
+        p for p in (parsed.quality, parsed.source, parsed.codec) if p
+    )
diff --git a/tests/application/test_enrich_from_probe.py b/tests/application/test_enrich_from_probe.py
index c192912..5e3a760 100644
--- a/tests/application/test_enrich_from_probe.py
+++ b/tests/application/test_enrich_from_probe.py
@@ -210,3 +210,42 @@ class TestLanguages:
         p = _bare()
         enrich_from_probe(p, MediaInfo())
         assert p.languages == []
+
+
+# --------------------------------------------------------------------------- #
+# tech_string                                                                  #
+# --------------------------------------------------------------------------- #
+
+
+class TestTechString:
+    """tech_string drives the filename builders; it must be re-derived
+    whenever quality / source / codec change."""
+
+    def test_rebuilt_from_filled_quality_and_codec(self):
+        p = _bare()
+        enrich_from_probe(
+            p, _info_with_video(width=1920, height=1080, codec="hevc")
+        )
+        assert p.quality == "1080p"
+        assert p.codec == "x265"
+        assert p.tech_string == "1080p.x265"
+
+    def test_keeps_existing_source_when_enriching(self):
+        # Token-level source must stay; probe fills only None fields.
+        p = _bare(source="BluRay")
+        enrich_from_probe(
+            p, _info_with_video(width=1920, height=1080, codec="hevc")
+        )
+        assert p.tech_string == "1080p.BluRay.x265"
+
+    def test_unchanged_when_no_enrichable_video_info(self):
+        # No video info → nothing to fill → tech_string stays as it was.
+        p = _bare(quality="2160p", source="WEB-DL", codec="x265")
+        p.tech_string = "2160p.WEB-DL.x265"
+        enrich_from_probe(p, MediaInfo())
+        assert p.tech_string == "2160p.WEB-DL.x265"
+
+    def test_empty_when_nothing_known(self):
+        p = _bare()
+        enrich_from_probe(p, MediaInfo())
+        assert p.tech_string == ""