diff --git a/crates/claude-connector/tests/fixtures/lease_v2/README.md b/crates/claude-connector/tests/fixtures/lease_v2/README.md
new file mode 100644
index 0000000..3cc9766
--- /dev/null
+++ b/crates/claude-connector/tests/fixtures/lease_v2/README.md
@@ -0,0 +1,16 @@
+# lease_v2 fixtures
+
+The exact bytes of the claude lease protocol v2: each file is one whole frame (a u32
+big-endian length, then the named-MessagePack map `{kind, value}`).
+
+- `request.bin`: `claude_lease_request`.
+- `refusal_unknown_caller.bin`, `refusal_expired.bin`, `refusal_busy.bin`,
+  `refusal_provider_rejected.bin`: `claude_lease_refusal`; `kind` is the variant name as a
+  PascalCase string.
+- `grant.bin`: `claude_lease_grant` with `lease_id` and `plan_quota` carrying `five_hour` and
+  `seven_day` windows (utilization_permille, resets_at_unix_ms, status, observed_at_unix_ms).
+  On the wire the grant travels with one SCM_RIGHTS fd; the file holds the frame only.
+
+Huginn's lease client vendors these files from this repository and tests against the same
+bytes. Generator: `tests/lease_wire_golden.rs`; run it with `LEASE_V2_REGENERATE=1`, then
+review the diff: a changed byte is a wire change.
diff --git a/crates/claude-connector/tests/lease.rs b/crates/claude-connector/tests/lease.rs
index 1128a06..2938070 100644
--- a/crates/claude-connector/tests/lease.rs
+++ b/crates/claude-connector/tests/lease.rs
@@ -543,3 +543,99 @@ fn connections_past_the_limit_are_dropped_and_finished_ones_free_their_place() {
     drop(first);
     assert!(granted_ok(&ask_until_granted(&harness, 2)));
 }
+
+#[test]
+fn a_lease_survives_many_polls_while_its_holder_and_invocation_stay() {
+    let harness = start(setup());
+    let mut first = ask(&harness, 60_000);
+    assert!(granted_ok(&first));
+    // Three polls later the lease still holds: a second invocation is Busy.
+    std::thread::sleep(Duration::from_millis(1_700));
+    harness.enter(2);
+    let second = ask(&harness, 60_000);
+    assert_eq!(refusal_of(&second), Some(LeaseRefusalKind::Busy));
+    // The holder talking does not end it either.
+    first._stream.write_all(b"x").unwrap();
+    std::thread::sleep(Duration::from_millis(1_200));
+    harness.enter(3);
+    assert_eq!(
+        refusal_of(&ask(&harness, 60_000)),
+        Some(LeaseRefusalKind::Busy)
+    );
+}
+
+#[test]
+fn a_lease_ends_when_the_unit_runs_a_different_invocation() {
+    let harness = start(setup());
+    let first = ask(&harness, 60_000);
+    assert!(granted_ok(&first));
+    // The same unit, a new invocation: the one that leased is over.
+    harness.enter(2);
+    std::thread::sleep(Duration::from_millis(1_200));
+    assert!(granted_ok(&ask(&harness, 60_000)));
+    drop(first);
+}
+
+#[test]
+fn a_lease_asks_the_system_about_its_holders_process_for_its_own_unit() {
+    let harness = start(setup());
+    let first = ask(&harness, 60_000);
+    assert!(granted_ok(&first));
+    std::thread::sleep(Duration::from_millis(1_200));
+    let asked = harness.units.as_ref().unwrap().asked_about.lock().unwrap().clone();
+    assert!(asked.len() >= 3, "the hold polled: {asked:?}");
+    assert!(asked.iter().all(|(_, unit)| unit == UNIT));
+}
+
+#[test]
+fn an_account_resolves_to_its_uid_and_a_missing_one_to_none() {
+    assert_eq!(claude_connector::user_uid("root"), Some(0));
+    assert_eq!(claude_connector::user_uid("no-such-account-4c1f9a"), None);
+    assert_eq!(claude_connector::user_uid("bad\0name"), None);
+}
+
+#[test]
+fn a_token_up_to_one_atomic_pipe_write_is_lent_and_a_longer_one_is_not() {
+    let exact: &'static str = Box::leak("a".repeat(4096).into_boxed_str());
+    let harness = start(Setup {
+        token: Some(exact),
+        ..setup()
+    });
+    let mut answer = ask(&harness, 60_000);
+    assert!(granted_ok(&answer));
+    let mut read = Vec::new();
+    File::from(answer.fds.remove(0))
+        .read_to_end(&mut read)
+        .unwrap();
+    assert_eq!(read.len(), 4096);
+
+    let long: &'static str = Box::leak("a".repeat(4097).into_boxed_str());
+    let harness = start(Setup {
+        token: Some(long),
+        ..setup()
+    });
+    let refused = ask(&harness, 60_000);
+    assert!(refused.message.is_none() && refused.fds.is_empty());
+}
+
+#[test]
+fn a_request_trickled_past_the_socket_timeout_is_dropped_without_a_lease() {
+    let harness = start(setup());
+    let mut stream = UnixStream::connect(&harness.socket).unwrap();
+    stream
+        .set_read_timeout(Some(Duration::from_secs(8)))
+        .unwrap();
+    stream.write_all(&[0, 0]).unwrap();
+    let started = Instant::now();
+    let mut byte = [0_u8; 1];
+    let outcome = stream.read(&mut byte);
+    // The listener gave up at its own two-second bound and closed the
+    // connection: end of file or a reset, never our own read timing out.
+    assert!(
+        matches!(outcome, Ok(0))
+            || outcome.as_ref().is_err_and(|e| e.kind() == std::io::ErrorKind::ConnectionReset),
+        "{outcome:?}"
+    );
+    assert!(started.elapsed() < Duration::from_secs(6));
+    assert_eq!(harness.tokens.reads.load(Ordering::SeqCst), 0);
+}
diff --git a/crates/claude-connector/tests/lease_wire_golden.rs b/crates/claude-connector/tests/lease_wire_golden.rs
new file mode 100644
index 0000000..e0edec2
--- /dev/null
+++ b/crates/claude-connector/tests/lease_wire_golden.rs
@@ -0,0 +1,95 @@
+//! Pins the bytes of the lease protocol v2: every frame a lease client sends
+//! or receives. The fixtures in `fixtures/lease_v2` are the contract's bytes
+//! for other implementations (Huginn's lease client vendors them and tests
+//! against the same bytes); the types in `claude_connector::lease` own the
+//! shape. Regenerate with `LEASE_V2_REGENERATE=1`, then review the diff.
+#![cfg(target_os = "linux")]
+
+use std::path::{Path, PathBuf};
+
+use claude_connector::{
+    LeaseGranted, LeaseMessage, LeaseRefusalKind, LeaseRefused, LeaseRequest, decode_frame,
+    encode_frame,
+};
+use model_connector::PlanQuota;
+
+const REGENERATE: &str = "LEASE_V2_REGENERATE";
+
+fn fixtures() -> PathBuf {
+    Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/fixtures/lease_v2")
+}
+
+fn assert_frame(name: &str, message: &LeaseMessage) {
+    let path = fixtures().join(name);
+    let bytes = encode_frame(message);
+    if std::env::var_os(REGENERATE).is_some() {
+        std::fs::create_dir_all(fixtures()).unwrap();
+        std::fs::write(&path, &bytes).unwrap();
+    }
+    let committed = std::fs::read(&path).unwrap_or_else(|_| panic!("{name} is missing"));
+    assert_eq!(committed, bytes, "{name} is not what the types encode");
+    assert_eq!(decode_frame(&committed).as_ref(), Some(message), "{name}");
+}
+
+#[test]
+fn the_request_frame_is_pinned() {
+    assert_frame(
+        "request.bin",
+        &LeaseMessage::ClaudeLeaseRequest(LeaseRequest {
+            expires_at_unix_ms: 1_793_307_000_000,
+        }),
+    );
+}
+
+#[test]
+fn every_refusal_frame_is_pinned_with_its_kind_as_a_pascal_case_string() {
+    let kinds = [
+        ("refusal_unknown_caller.bin", LeaseRefusalKind::UnknownCaller, "UnknownCaller"),
+        ("refusal_expired.bin", LeaseRefusalKind::Expired, "Expired"),
+        ("refusal_busy.bin", LeaseRefusalKind::Busy, "Busy"),
+        (
+            "refusal_provider_rejected.bin",
+            LeaseRefusalKind::ProviderRejected,
+            "ProviderRejected",
+        ),
+    ];
+    for (name, kind, spelled) in kinds {
+        let message = LeaseMessage::ClaudeLeaseRefusal(LeaseRefused {
+            kind,
+            detail: "the reason".to_string(),
+        });
+        assert_frame(name, &message);
+        // The kind travels as the variant's name, which other runtimes read.
+        let bytes = encode_frame(&message);
+        let value: rmpv::Value = rmp_serde::from_slice(&bytes[4..]).unwrap();
+        let rmpv::Value::Map(outer) = value else {
+            panic!("a frame is a map")
+        };
+        let rmpv::Value::Map(inner) = &outer[1].1 else {
+            panic!("the value is a map")
+        };
+        assert_eq!(inner[0].0.as_str(), Some("kind"));
+        assert_eq!(inner[0].1.as_str(), Some(spelled));
+    }
+}
+
+#[test]
+fn a_grant_with_both_usage_windows_is_pinned() {
+    let window = |name: &str, permille, status: &str, resets| PlanQuota {
+        window: name.to_string(),
+        utilization_permille: Some(permille),
+        resets_at_unix_ms: resets,
+        status: status.to_string(),
+        observed_at_unix_ms: 1_793_300_000_000,
+    };
+    assert_frame(
+        "grant.bin",
+        &LeaseMessage::ClaudeLeaseGrant(LeaseGranted {
+            lease_id: "lease:0123456789abcdef0123456789abcdef".to_string(),
+            plan_quota: vec![
+                window("five_hour", 420, "allowed", 1_793_307_000_000),
+                window("seven_day", 999, "allowed_warning", 1_793_800_000_000),
+            ],
+        }),
+    );
+}