--- a/crates/aiflow-analyze/src/lib.rs
+++ b/crates/aiflow-analyze/src/lib.rs
@@ -337,8 +337,15 @@
         let row = entries.iter().find(|r|r[key].as_str()==Some(name.as_str())).ok_or_else(||format!("Fields did not solve {group}.{name}; resolve its missing terminals or copper and rerun analyze"))?;
         if kind == "thermal" {
             let watts = value["watts"].as_f64().unwrap();
+            // Fields explicitly calls a source without a declared thermal tab "leads".
+            // Match that model only; a named tab net must still match exactly.
+            let tab_matches = if value.get("tabNet").is_none_or(Value::is_null) {
+                row["tabNet"] == "leads"
+            } else {
+                row["tabNet"] == value["tabNet"]
+            };
             if !row["watts"].as_f64().is_some_and(|v| v.is_finite() && (v-watts).abs() <= 1e-8)
-                || row["tabNet"] != value["tabNet"] {
+                || !tab_matches {
                 return Err(format!("Fields {name} thermal source differs from its declared watts or tab net"));
             }
             let rise_limit = value.get("maxRiseC").or_else(|| spec.get("hotMaxRiseC"));
@@ -482,6 +489,22 @@
         f
     }
     #[test]
+    fn lead_cooled_sources_match_only_the_fields_leads_model() {
+        let spec=json!({"hotMaxRiseC":35,"hot":{"Q1":{"watts":5}}});
+        let mut f=thermal_report();f["chips"][0]["tabNet"]=json!("leads");
+        field_screen(&f,&spec,b"board",b"spec","thermal").unwrap();
+        for net in [Value::Null,json!(""),json!("GND"),json!("VCC")] {
+            let mut bad=f.clone();bad["chips"][0]["tabNet"]=net;
+            assert!(field_screen(&bad,&spec,b"board",b"spec","thermal").is_err());
+        }
+        let mut over=f.clone();over["chips"][0]["riseC"]=json!(35.0);
+        assert!(field_screen(&over,&spec,b"board",b"spec","thermal").is_err());
+        let mut stale=f.clone();stale["inputIdentity"]["board"]=json!("old");
+        assert!(field_screen(&stale,&spec,b"board",b"spec","thermal").is_err());
+        let named=json!({"hotMaxRiseC":35,"hot":{"Q1":{"watts":5,"tabNet":"VCC"}}});
+        assert!(field_screen(&f,&named,b"board",b"spec","thermal").is_err());
+    }
+    #[test]
     fn individual_thermal_limit_and_rounding_allowance_are_enforced() {
         let spec=json!({"hotMaxRiseC":35,"hot":{"Q1":{"watts":5,"tabNet":"VCC","maxRiseC":15}}});
         field_screen(&thermal_report(),&spec,b"board",b"spec","thermal").unwrap();