diff --git a/work/meshai/transport/meshcore_transport.py b/work/meshai/transport/meshcore_transport.py
index ba7a228..3796b4f 100644
--- a/work/meshai/transport/meshcore_transport.py
+++ b/work/meshai/transport/meshcore_transport.py
@@ -1224,10 +1224,16 @@ class MeshCoreTransport(MeshTransport):
     # Telemetry (MeshCore sensor auto-poll)
     # ------------------------------------------------------------------
 
-    def _resolve_contact(self, contact_id: str):
+    def _resolve_contact_for_telemetry(self, contact_id: str):
         """Resolve *contact_id* (a pubkey/prefix OR a name) to a contact dict.
 
-        Mirrors DM / get_node_name resolution: try key-prefix first, then name.
+        Telemetry-only resolver: try key-prefix first, then name. Unlike
+        ``_resolve_contact`` (the DM/path-establishment resolver), this does
+        NOT force a full ``get_contacts(lastmod=0)`` refetch on a cache miss —
+        telemetry only ever targets contacts the operator has explicitly
+        selected in ``meshcore_telemetry_contacts``, which are expected to
+        already be in the roster (added via a prior DM/advert), so the extra
+        firmware round-trip isn't worth paying on every poll cycle.
         Returns the raw contact dict, or None if not resolvable / not connected.
         """
         if self._mc is None or not self._connected:
@@ -1315,7 +1321,7 @@ class MeshCoreTransport(MeshTransport):
 
         Returns the decoded dict, or None on unresolved/timeout/no-response/error.
         """
-        contact = self._resolve_contact(contact_id)
+        contact = self._resolve_contact_for_telemetry(contact_id)
         if contact is None:
             return None
         try:
diff --git a/work/tests/test_no_duplicate_methods.py b/work/tests/test_no_duplicate_methods.py
new file mode 100644
index 0000000..54defce
--- /dev/null
+++ b/work/tests/test_no_duplicate_methods.py
@@ -0,0 +1,131 @@
+"""Guard test: no class in meshai/ may define the same method name twice.
+
+Motivation (issue #127): ``MeshCoreTransport`` defined ``_resolve_contact``
+TWICE — once at module-load-earlier line 171 (PR #56's refetch-on-miss DM
+resolver) and again later at line 1227 (PR #92's telemetry resolver, added
+independently and never noticed it collided with an existing name). Python
+silently keeps only the LAST definition in a class body; the first is not an
+error, a warning, or even visible to static type checkers or linters in the
+configurations this project runs. The result: every caller of the first
+implementation silently got the second implementation's (materially
+different) behavior instead, for months, with no signal anywhere.
+
+This test AST-parses every .py file under meshai/ and asserts that no
+ClassDef body defines the same (non-overload, non-property-pair) function
+name more than once. It is a static, source-level check — it doesn't need
+the module to be importable (meshai.main can't be imported in this test env
+at all; see test_central_boot_guard.py), so it runs over the raw source tree.
+
+Legitimate duplicate-name patterns that must NOT be flagged:
+  - ``@property`` / ``@x.setter`` / ``@x.deleter`` triplets (same name by
+    design — that's how Python properties work).
+  - ``@typing.overload`` stacks (multiple signatures, same name, followed by
+    exactly one real implementation) — a standard typing idiom.
+  - ``@overload`` from other modules aliased/imported differently is treated
+    the same way: any decorator whose name (attribute or plain) ends in
+    "overload" or is exactly "property"/"setter"/"deleter" (as a `.` attr)
+    exempts that definition from the duplicate count.
+"""
+
+from __future__ import annotations
+
+import ast
+import pathlib
+
+import pytest
+
+REPO_ROOT = pathlib.Path(__file__).resolve().parent.parent
+MESHAI_ROOT = REPO_ROOT / "meshai"
+
+
+def _iter_python_files(root: pathlib.Path):
+    yield from root.rglob("*.py")
+
+
+def _decorator_names(node: ast.AST) -> list[str]:
+    """Return the flat list of decorator names on a function/method def.
+
+    Handles ``@overload``, ``@typing.overload`` (Attribute), ``@property``,
+    ``@x.setter``, ``@x.deleter`` (Attribute with .attr == setter/deleter).
+    """
+    names = []
+    for dec in getattr(node, "decorator_list", []):
+        target = dec
+        # Decorators can be bare Name/Attribute, or a Call wrapping one
+        # (e.g. @some_decorator(...)) — unwrap the call to get at the name.
+        if isinstance(target, ast.Call):
+            target = target.func
+        if isinstance(target, ast.Attribute):
+            names.append(target.attr)
+        elif isinstance(target, ast.Name):
+            names.append(target.id)
+    return names
+
+
+def _is_exempt(node: ast.AST) -> bool:
+    """True if this def's decorators mark it as a legitimate same-name reuse."""
+    for name in _decorator_names(node):
+        if name in ("setter", "deleter", "property"):
+            return True
+        if name.endswith("overload"):  # overload / typing.overload
+            return True
+    return False
+
+
+def _find_duplicate_methods_in_class(cls: ast.ClassDef) -> dict[str, int]:
+    """Return {method_name: count} for names defined >1 time in *cls*,
+    excluding property accessor groups and @overload stacks."""
+    counts: dict[str, int] = {}
+    for stmt in cls.body:
+        if isinstance(stmt, (ast.FunctionDef, ast.AsyncFunctionDef)):
+            if _is_exempt(stmt):
+                continue
+            counts[stmt.name] = counts.get(stmt.name, 0) + 1
+    return {name: n for name, n in counts.items() if n > 1}
+
+
+def _collect_all_duplicates() -> dict[str, dict[str, int]]:
+    """Walk every class in every .py file under meshai/; return
+    {"path.py::ClassName": {method_name: count}} for classes with dupes."""
+    findings: dict[str, dict[str, int]] = {}
+    for path in _iter_python_files(MESHAI_ROOT):
+        try:
+            source = path.read_text(encoding="utf-8")
+            tree = ast.parse(source, filename=str(path))
+        except (SyntaxError, UnicodeDecodeError):
+            continue
+        for node in ast.walk(tree):
+            if isinstance(node, ast.ClassDef):
+                dupes = _find_duplicate_methods_in_class(node)
+                if dupes:
+                    rel = path.relative_to(REPO_ROOT)
+                    findings[f"{rel}::{node.name}"] = dupes
+    return findings
+
+
+def test_no_class_defines_the_same_method_twice():
+    """Fails if ANY class body in meshai/ defines a method name more than
+    once (excluding @property/@setter/@deleter groups and @overload stacks).
+
+    This is exactly the failure mode from issue #127: MeshCoreTransport had
+    two ``_resolve_contact`` defs and Python silently kept only the second.
+    """
+    findings = _collect_all_duplicates()
+    assert not findings, (
+        "Duplicate method name(s) found within a single class body — Python "
+        "silently keeps only the LAST definition, discarding the others with "
+        "no error/warning (see issue #127). Fix by renaming or merging:\n"
+        + "\n".join(f"  {cls}: {dupes}" for cls, dupes in sorted(findings.items()))
+    )
+
+
+def test_guard_sanity_meshai_root_is_populated():
+    """Sanity check the guard actually scanned files (protects against a
+    silently-empty rglob due to a path typo hiding a real bug forever)."""
+    files = list(_iter_python_files(MESHAI_ROOT))
+    assert len(files) > 10, f"expected many .py files under {MESHAI_ROOT}, found {len(files)}"
+
+
+if __name__ == "__main__":
+    import sys
+    sys.exit(pytest.main([__file__, "-v"]))