diff --git a/adam/tests/run-tests.sh b/adam/tests/run-tests.sh
index a9061c6..023a4b2 100755
--- a/adam/tests/run-tests.sh
+++ b/adam/tests/run-tests.sh
@@ -631,6 +631,27 @@ else
   echo "  FAIL: hex/epoch fingerprint mismatch (a=$fp_a b=$fp_b)"; FAIL=$((FAIL+1))
 fi
 
+# --- Test 36b: fingerprint — file-tool success objects are not errors ---
+echo "Test 36b: Read/Edit/Write success objects with error words return null"
+fp_r=$(node -e "import('$HOOK').then(m => console.log(m.errorFingerprint({type:'text',file:{filePath:'/x/cache.go',content:'return fmt.Errorf(\"failed: not found\")'}})))")
+fp_e=$(node -e "import('$HOOK').then(m => console.log(m.errorFingerprint({filePath:'/x/a.ts',oldString:'throw new Error(1)',newString:'x',originalFile:'undefined error'})))")
+fp_w=$(node -e "import('$HOOK').then(m => console.log(m.errorFingerprint({type:'create',filePath:'/x/b.ts',content:'const errorRateTier = \"failed\"'})))")
+if [ "$fp_r" = "null" ] && [ "$fp_e" = "null" ] && [ "$fp_w" = "null" ]; then
+  echo "  PASS: file-tool success shapes not fingerprinted"; PASS=$((PASS+1))
+else
+  echo "  FAIL: success shape fingerprinted (r=$fp_r e=$fp_e w=$fp_w)"; FAIL=$((FAIL+1))
+fi
+
+# --- Test 36c: fingerprint — real error shapes still fingerprinted ---
+echo "Test 36c: is_error:true with filePath and plain error strings still fingerprint"
+fp_x=$(node -e "import('$HOOK').then(m => console.log(m.errorFingerprint({is_error:true,filePath:'/x/a.ts',content:'String to replace not found in file.'})))")
+fp_s=$(node -e "import('$HOOK').then(m => console.log(m.errorFingerprint('Error: result (70,310 characters) exceeds maximum allowed tokens')))")
+if [ "$fp_x" != "null" ] && [ "$fp_s" != "null" ]; then
+  echo "  PASS: error shapes keep fingerprints ($fp_x, $fp_s)"; PASS=$((PASS+1))
+else
+  echo "  FAIL: error shape lost fingerprint (x=$fp_x s=$fp_s)"; FAIL=$((FAIL+1))
+fi
+
 # --- Test 37: correction corpus — strong tokens fire ---
 echo "Test 37: strong-correction tokens each emit correction signal"
 strong_ok=1
diff --git a/hooks/adam-observe.mjs b/hooks/adam-observe.mjs
index 386a65b..b99bb47 100755
--- a/hooks/adam-observe.mjs
+++ b/hooks/adam-observe.mjs
@@ -249,6 +249,12 @@ function snapshotContext(state) {
 
 function errorFingerprint(toolResponse) {
   if (!toolResponse) return null;
+  // Read/Edit/Write success objects carry `file`/`filePath` and no `is_error`.
+  // PostToolUse never receives failed calls (CC routes them to
+  // PostToolUseFailure), so ERROR_RE here would only match source-file text.
+  if (typeof toolResponse === "object" && !Array.isArray(toolResponse) &&
+      toolResponse.is_error !== true &&
+      ("file" in toolResponse || "filePath" in toolResponse)) return null;
   let text = "";
   if (typeof toolResponse === "string") text = toolResponse;
   else if (toolResponse.content !== undefined) {