diff --git a/crates/aura-cli/tests/cli_run.rs b/crates/aura-cli/tests/cli_run.rs
index 1b70856..27d1056 100644
--- a/crates/aura-cli/tests/cli_run.rs
+++ b/crates/aura-cli/tests/cli_run.rs
@@ -3039,6 +3039,114 @@ fn generalize_without_explicit_window_falls_back_to_the_first_symbols_full_windo
     assert!(stdout.contains("\"family_id\":\"generalize-0\""), "family handle: {stdout}");
 }
 
+/// Property (#213, no-window semantics): invoked WITHOUT `--from`/`--to`, a
+/// multi-symbol `generalize` resolves the ONE shared campaign window as the
+/// INTERSECTION of the listed symbols' full archive windows — the latest start
+/// and earliest end, i.e. the only span over which EVERY listed instrument
+/// actually has data. `generalize` is the cross-instrument comparison (the
+/// worst-case R floor, #146); a floor pooled over a different period per
+/// instrument conflates the instrument axis with the period axis, so the common
+/// window is the only one that isolates what the verb measures. Today's fallback
+/// picks `symbols[0]`'s full window alone (the superseded shape test above):
+/// listing the WIDER symbol first (`AAPL.US`, archive from 2006) keeps AAPL's
+/// early start, whereas the intersection with the later-starting `GER40` (archive
+/// from 2014) must start at GER40's first bar and end at whichever archive ends
+/// first — so on the current tree the resolved window differs from the
+/// intersection on both bounds. Each symbol's full window is resolved
+/// independently here: a single-symbol `sweep` with no window records it into its
+/// generated campaign document, in the same Unix-ms currency and via the same
+/// `campaign_window_ms(full_window)` probe generalize itself resolves against —
+/// so the expected intersection is derived from the live archive, never a
+/// hard-coded span that shifts as the archive grows. Archive-gated; skips
+/// cleanly on a data-less host.
+#[test]
+fn generalize_without_explicit_window_resolves_the_intersection_of_all_symbols() {
+    if !local_data_present() {
+        eprintln!("skip: no local data at {}", data_server::DEFAULT_DATA_PATH);
+        return;
+    }
+    let (cwd, _g) = fresh_project();
+    let fixture = format!("{}/examples/r_sma_open.json", env!("CARGO_MANIFEST_DIR"));
+
+    // The resolved shared window persists verbatim in the generated campaign
+    // document; read the (from_ms, to_ms) of the one whose `name` field matches.
+    let window_of = |name: &str| -> (i64, i64) {
+        let dir = cwd.join("runs").join("campaigns");
+        for entry in std::fs::read_dir(&dir).expect("campaigns dir exists after a run") {
+            let path = entry.expect("readable dir entry").path();
+            let doc: serde_json::Value =
+                serde_json::from_str(&std::fs::read_to_string(&path).expect("read campaign doc"))
+                    .expect("campaign doc parses as JSON");
+            if doc["name"].as_str() == Some(name) {
+                let w = &doc["data"]["windows"][0];
+                return (
+                    w["from_ms"].as_i64().expect("from_ms is an integer"),
+                    w["to_ms"].as_i64().expect("to_ms is an integer"),
+                );
+            }
+        }
+        panic!("no campaign document named {name:?} in {}", dir.display());
+    };
+
+    // Resolve one symbol's full archive window by running a single-symbol,
+    // single-cell sweep with NO --from/--to; the window it records is exactly the
+    // `campaign_window_ms(full_window)` value generalize resolves per symbol.
+    let probe = |symbol: &str, name: &str| -> (i64, i64) {
+        let out = std::process::Command::new(env!("CARGO_BIN_EXE_aura"))
+            .args([
+                "sweep", &fixture, "--real", symbol,
+                "--axis", "sma_signal.fast.length=3", "--axis", "sma_signal.slow.length=12",
+                "--name", name,
+            ])
+            .current_dir(cwd)
+            .output()
+            .expect("spawn aura sweep");
+        assert_eq!(
+            out.status.code(), Some(0),
+            "single-symbol window-probe sweep for {symbol} must run to exit 0: {}",
+            String::from_utf8_lossy(&out.stderr)
+        );
+        window_of(name)
+    };
+
+    let aapl = probe("AAPL.US", "probe-aapl");
+    let ger40 = probe("GER40", "probe-ger40");
+    // Precondition: the archives genuinely differ, so "the intersection" is a
+    // distinct claim from "symbols[0]'s full window" (else the test is vacuous).
+    assert_ne!(
+        aapl, ger40,
+        "AAPL.US {aapl:?} and GER40 {ger40:?} must span different windows for the test to bite"
+    );
+
+    // The contract: the shared window is the intersection — latest start, earliest end.
+    let expected = (aapl.0.max(ger40.0), aapl.1.min(ger40.1));
+
+    // AAPL.US listed FIRST: today's `symbols[0]` fallback keeps AAPL's (wider)
+    // window, which differs from the intersection on both bounds — so a pass here
+    // can only mean the intersection semantics landed.
+    let out = std::process::Command::new(env!("CARGO_BIN_EXE_aura"))
+        .args([
+            "generalize", &fixture, "--real", "AAPL.US,GER40",
+            "--axis", "sma_signal.fast.length=3", "--axis", "sma_signal.slow.length=12",
+            "--name", "gen-both",
+        ])
+        .current_dir(cwd)
+        .output()
+        .expect("spawn aura generalize");
+    assert_eq!(
+        out.status.code(), Some(0),
+        "two-symbol no-window generalize must run to exit 0: {}",
+        String::from_utf8_lossy(&out.stderr)
+    );
+    let resolved = window_of("gen-both");
+
+    assert_eq!(
+        resolved, expected,
+        "no-window generalize must resolve the INTERSECTION {expected:?} of AAPL.US {aapl:?} \
+         and GER40 {ger40:?} — not symbols[0]'s ({aapl:?}) full window (resolved {resolved:?})"
+    );
+}
+
 /// Property: a single-instrument generalize is refused at parse time (exit 2),
 /// before any data access — so it asserts the arity refusal on any machine.
 #[test]