diff --git a/roar/filters/omit.py b/roar/filters/omit.py
index ebd85356..868f49c2 100644
--- a/roar/filters/omit.py
+++ b/roar/filters/omit.py
@@ -159,12 +159,36 @@ def was_modified(self) -> bool:
         re.compile(r"(hooks\.slack\.com/services/)([A-Z0-9/]+)", re.IGNORECASE),
         r"\1[REDACTED]",
     ),
-    # Environment variable assignments in commands
+    # Environment variable assignments in commands.
+    #
+    # Case-sensitive, and a single "=" only. Both restrictions are load-bearing.
+    #
+    # This rule matched any name CONTAINING key/token/secret/..., case-insensitively,
+    # followed by "=". A pip requirement satisfies that: "tiktoken==0.12.0" is a name
+    # ending in "token" followed by "=", so the VERSION was redacted as if it were a
+    # credential. A published freeze then carried
+    #
+    #     'tiktoken==[REDACTED]'
+    #
+    # which no installer can execute, so the recorded environment could not be rebuilt
+    # -- the one thing the freeze exists to make possible. It cost a 3.5-hour training
+    # run its reproducibility gate, and it is not specific to tiktoken: authlib,
+    # keyring, tokenizers and python-jose all contain a keyword.
+    #
+    # Environment variables are uppercase by convention, and POSIX reserves that space
+    # for them, so dropping IGNORECASE keeps HF_TOKEN=, API_KEY= and MYTOKEN= while
+    # sparing every lowercase package name. Requiring a single "=" spares version pins
+    # regardless of case.
+    #
+    # The gap this leaves is a lowercase-named variable holding a secret with no
+    # recognisable prefix (hf_token=..., where the value is not hf_...). That is
+    # unconventional, and the value-shaped rules above -- hf_, sk-, ghp_, glpat-, AKIA
+    # -- catch the real providers by their token format rather than by variable name.
     (
         "env_var_assignment",
         re.compile(
-            r"([A-Z_]*(?:KEY|TOKEN|SECRET|PASSWORD|PASSWD|PWD|CREDENTIAL|AUTH)[A-Z_]*)=([^\s]+)",
-            re.IGNORECASE,
+            r"([A-Z_]*(?:KEY|TOKEN|SECRET|PASSWORD|PASSWD|PWD|CREDENTIAL|AUTH)[A-Z_]*)"
+            r"(?<!=)=(?!=)([^\s]+)"
         ),
         r"\1=[REDACTED]",
     ),
diff --git a/tests/unit/test_omit_filter_version_pins.py b/tests/unit/test_omit_filter_version_pins.py
new file mode 100644
index 00000000..838aeb64
--- /dev/null
+++ b/tests/unit/test_omit_filter_version_pins.py
@@ -0,0 +1,100 @@
+"""A version pin is not a credential.
+
+The env-var rule matched any name *containing* key/token/secret/..., case
+insensitively, followed by "=". A pip requirement satisfies that: ``tiktoken==0.12.0``
+is a name ending in "token" followed by "=", so the VERSION was redacted. A published
+freeze then carried ``'tiktoken==[REDACTED]'``, which no installer can execute — the
+recorded environment could not be rebuilt, which is the one thing a freeze exists to
+make possible.
+
+These pin both directions against the real patterns: package pins survive, and actual
+environment assignments are still redacted.
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from roar.filters.omit import OmitFilter
+
+# Assembled at runtime so secret scanners do not flag the fixtures as real credentials.
+FAKE_HF_TOKEN = "hf_" + "AbCdEfGhIjKlMnOpQrStUvWxYz012345"
+FAKE_OPENAI_KEY = "sk-" + "AbCdEfGhIjKlMnOpQrStUv"
+
+
+@pytest.fixture()
+def omit_filter() -> OmitFilter:
+    return OmitFilter({})
+
+
+# Every one of these contains a keyword the rule looks for, and every one is a
+# dependency people really install.
+PACKAGE_PINS = [
+    pytest.param("tiktoken==0.12.0", id="tiktoken"),
+    pytest.param("authlib==1.3.2", id="authlib"),
+    pytest.param("keyring==25.4.1", id="keyring"),
+    pytest.param("tokenizers==0.20.3", id="tokenizers"),
+    pytest.param("python-jose[cryptography]==3.3.0", id="python-jose"),
+    pytest.param("secretstorage==3.3.3", id="secretstorage"),
+]
+
+
+@pytest.mark.parametrize("requirement", PACKAGE_PINS)
+def test_package_pin_survives_filtering(omit_filter: OmitFilter, requirement: str) -> None:
+    result = omit_filter.filter_string(requirement, field="packages")
+
+    assert result.filtered == requirement
+    assert result.detections == []
+
+
+def test_full_install_command_survives(omit_filter: OmitFilter) -> None:
+    # The shape that actually broke: a generated install line from a freeze. If any
+    # version is replaced the command cannot be executed literally, which is exactly
+    # the failure the reproducibility gate catches -- after the compute is spent.
+    command = "pip install torch==2.9.1 tiktoken==0.12.0 regex==2025.9.1 authlib==1.3.2"
+
+    result = omit_filter.filter_string(command, field="command")
+
+    assert result.filtered == command
+    assert "[REDACTED]" not in result.filtered
+
+
+ENV_ASSIGNMENTS = [
+    pytest.param(f"HF_TOKEN={FAKE_HF_TOKEN}", "HF_TOKEN", id="hf-token"),
+    pytest.param(f"OPENAI_API_KEY={FAKE_OPENAI_KEY}", "OPENAI_API_KEY", id="openai-key"),
+    pytest.param("MYTOKEN=abc123def456", "MYTOKEN", id="unprefixed-uppercase"),
+    pytest.param("DB_PASSWORD=hunter2hunter2", "DB_PASSWORD", id="password"),
+    pytest.param("AWS_SECRET=abcdefghijklmnop", "AWS_SECRET", id="secret"),
+]
+
+
+@pytest.mark.parametrize("assignment,name", ENV_ASSIGNMENTS)
+def test_environment_assignment_is_still_redacted(
+    omit_filter: OmitFilter, assignment: str, name: str
+) -> None:
+    # The reason the rule exists. Narrowing it must not cost this.
+    result = omit_filter.filter_string(assignment, field="command")
+
+    assert result.filtered == f"{name}=[REDACTED]"
+    assert assignment.split("=", 1)[1] not in result.filtered
+
+
+def test_assignment_inside_a_command_is_still_redacted(omit_filter: OmitFilter) -> None:
+    command = f"env HF_TOKEN={FAKE_HF_TOKEN} python -m scripts.base_train --depth=14"
+
+    result = omit_filter.filter_string(command, field="command")
+
+    assert FAKE_HF_TOKEN not in result.filtered
+    assert "HF_TOKEN=[REDACTED]" in result.filtered
+    # The unrelated argument must survive intact.
+    assert "--depth=14" in result.filtered
+
+
+def test_provider_token_is_caught_by_value_even_when_the_name_is_lowercase(
+    omit_filter: OmitFilter,
+) -> None:
+    # The gap the narrowing leaves is a lowercase variable name. Real providers are
+    # still caught by the shape of the value, which is why that gap is acceptable.
+    result = omit_filter.filter_string(f"hf_token={FAKE_HF_TOKEN}", field="command")
+
+    assert FAKE_HF_TOKEN not in result.filtered