diff --git a/MODULE.md b/MODULE.md
index 92ecc935..c3811987 100644
--- a/MODULE.md
+++ b/MODULE.md
@@ -11,7 +11,7 @@ RPC methods. Configuration requires `contract_version` and `policy`. The optiona
 
 ```json
 {
-  "contract_version": [1, 12],
+  "contract_version": [2, 0],
   "policy": {
     "enabled": false,
     "action_dir": "",
@@ -385,6 +385,9 @@ returned by `ListToolTrust2` even when the tool's display label is redacted; the
 module verifies the row belongs to the supplied registered scope and records the
 usual audited cancellation.
 
+Approval execution outcomes and the contract 2.0 compatibility boundary are
+described in [`docs/specs/approval-execution-outcomes.md`](docs/specs/approval-execution-outcomes.md).
+
 ### Scored prompt screening: `ScanPrompt2`
 
 `ScanPrompt2 { text }` answers `{ tier, score_milli, rule_ids }`. The tier is `allow`, `review` or
diff --git a/README.md b/README.md
index 77c288b4..16b79329 100644
--- a/README.md
+++ b/README.md
@@ -11,6 +11,10 @@ Contract 1.25 adds `DevicePairing2`, which owns the paired-device static
 identity, ciphertext-only persistence, host-attested enrollment/reconnect,
 session refresh and revocation while preserving the existing v2/v3/v4 wire;
 see the [pairing lifecycle specification](docs/specs/device-pairing-contract-1.25.md).
+Contract 2.0 adds the `abandoned` approval execution outcome for in-flight
+executions whose effects could not be determined. Because `ExecutionOutcome` is
+a closed wire enum, 1.x hosts reject 2.x modules rather than risk decoding a
+result they cannot represent; see the [approval contract](docs/specs/approval-execution-outcomes.md).
 Contract 1.1 also supplies immutable native [filesystem scopes](docs/specs/immutable-path-scopes.md)
 through `RegisterPathPolicy`, `ValidatePath`, `ValidateParent` and `CheckPath`.
 Contract 1.3 adds native `Redact`, `ScanPrompt` and `ScanToolDefinition`, with a
diff --git a/crates/tinysecurity-approval/src/engine_tests.rs b/crates/tinysecurity-approval/src/engine_tests.rs
index e5a00092..f565fe22 100644
--- a/crates/tinysecurity-approval/src/engine_tests.rs
+++ b/crates/tinysecurity-approval/src/engine_tests.rs
@@ -429,6 +429,35 @@ fn action(row: &ApprovalRow2, phase: u64) -> ApprovalActionRequest2 {
     }
 }
 #[tokio::test]
+async fn abandoned_execution_is_persisted_as_an_immutable_unknown_effect() -> Result<()> {
+    let f = Arc::new(Fixture::default());
+    let owner = engine(f, Arc::new(TestClock::default()))?;
+    let row = owner.begin(request()).await?;
+    owner.decide(decision(&row)).await?;
+    owner.consume(action(&row, 3)).await?;
+
+    let terminal = RecordExecutionRequest2 {
+        action: action(&row, 4),
+        outcome: ExecutionOutcome::Abandoned,
+    };
+    let finished = owner.record_execution(terminal.clone()).await?;
+    assert_eq!(finished.state, ApprovalLifecycle2::Executed);
+    assert_eq!(finished.outcome, Some(ExecutionOutcome::Abandoned));
+    assert_eq!(
+        owner.list(&request().scope_id).await?,
+        vec![finished.clone()]
+    );
+    assert_eq!(owner.record_execution(terminal).await?, finished);
+
+    let mut cancelled = RecordExecutionRequest2 {
+        action: action(&row, 4),
+        outcome: ExecutionOutcome::Cancelled,
+    };
+    cancelled.action.audit = audit(5);
+    assert!(owner.record_execution(cancelled).await.is_err());
+    Ok(())
+}
+#[tokio::test]
 async fn exact_human_ticket_first_winner_once_consumption_and_terminal_outcome() -> Result<()> {
     let f = Arc::new(Fixture::default());
     let owner = engine(f, Arc::new(TestClock::default()))?;
diff --git a/crates/tinysecurity-bus/src/approval.rs b/crates/tinysecurity-bus/src/approval.rs
index d75e7c83..79e24c34 100644
--- a/crates/tinysecurity-bus/src/approval.rs
+++ b/crates/tinysecurity-bus/src/approval.rs
@@ -300,7 +300,7 @@ impl ExecutionOutcome {
         match value {
             "success" => Ok(Self::Succeeded),
             "failure" => Ok(Self::Failed),
-            "aborted" => Ok(Self::Cancelled),
+            "aborted" => Ok(Self::Abandoned),
             _ => Err(crate::Error::InvalidArguments),
         }
     }
diff --git a/crates/tinysecurity-bus/src/approval_tests.rs b/crates/tinysecurity-bus/src/approval_tests.rs
index f4256b04..c230797b 100644
--- a/crates/tinysecurity-bus/src/approval_tests.rs
+++ b/crates/tinysecurity-bus/src/approval_tests.rs
@@ -11,7 +11,7 @@ fn legacy_execution_outcomes_are_explicit_and_unknown_values_reject() {
     );
     assert_eq!(
         ExecutionOutcome::from_legacy("aborted"),
-        Ok(ExecutionOutcome::Cancelled)
+        Ok(ExecutionOutcome::Abandoned)
     );
     assert!(ExecutionOutcome::from_legacy("approved").is_err());
 }
diff --git a/crates/tinysecurity-bus/src/device_frame_tests.rs b/crates/tinysecurity-bus/src/device_frame_tests.rs
index ec64d356..3a1c0d57 100644
--- a/crates/tinysecurity-bus/src/device_frame_tests.rs
+++ b/crates/tinysecurity-bus/src/device_frame_tests.rs
@@ -70,5 +70,5 @@ fn frame_operations_redact_both_payloads_without_changing_open_wire_shape()
 #[test]
 fn frame_member_name_is_stable_and_contract_version_is_bumped() {
     assert_eq!(crate::names::methods::DEVICE_FRAME2, "DeviceFrame2");
-    assert_eq!(crate::CONTRACT_VERSION, (1, 29));
+    assert_eq!(crate::CONTRACT_VERSION, (2, 0));
 }
diff --git a/crates/tinysecurity-bus/src/device_pairing_tests.rs b/crates/tinysecurity-bus/src/device_pairing_tests.rs
index ce8974fe..d1aeaea1 100644
--- a/crates/tinysecurity-bus/src/device_pairing_tests.rs
+++ b/crates/tinysecurity-bus/src/device_pairing_tests.rs
@@ -85,7 +85,7 @@ fn refresh_and_close_are_distinct_transient_session_operations() {
 
 #[test]
 fn pairing_contract_is_versioned_after_the_frame_contract() {
-    assert_eq!(CONTRACT_VERSION, (1, 29));
+    assert_eq!(CONTRACT_VERSION, (2, 0));
 }
 
 #[test]
diff --git a/crates/tinysecurity-bus/src/future.rs b/crates/tinysecurity-bus/src/future.rs
index 6de58fad..b42dda0d 100644
--- a/crates/tinysecurity-bus/src/future.rs
+++ b/crates/tinysecurity-bus/src/future.rs
@@ -20,7 +20,7 @@ pub enum ApprovalState {
     /// Executed state.
     Executed,
 }
-/// `ExecutionOutcome` vocabulary, reserved until its engine is implemented.
+/// Terminal execution result, including runs abandoned before their effects were known.
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "snake_case")]
 pub enum ExecutionOutcome {
@@ -30,6 +30,8 @@ pub enum ExecutionOutcome {
     Failed,
     /// Cancelled state.
     Cancelled,
+    /// The in-flight execution was abandoned before its effects could be determined.
+    Abandoned,
 }
 /// `ReplyVerdict` vocabulary, reserved until its engine is implemented.
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
diff --git a/crates/tinysecurity-bus/src/lib.rs b/crates/tinysecurity-bus/src/lib.rs
index 633dab84..9b935175 100644
--- a/crates/tinysecurity-bus/src/lib.rs
+++ b/crates/tinysecurity-bus/src/lib.rs
@@ -65,7 +65,7 @@ pub use scoped_policy::*;
 pub use tool_trust::*;
 pub mod names;
 /// Current wire vocabulary version, independent of the artifact version.
-pub const CONTRACT_VERSION: (u32, u32) = (1, 29);
+pub const CONTRACT_VERSION: (u32, u32) = (2, 0);
 /// Whether a remote module's advertised version supplies this host's vocabulary.
 ///
 /// `version` is the provider version received by the host, not a host requirement
diff --git a/crates/tinysecurity-bus/tests/fixtures/v1.json b/crates/tinysecurity-bus/tests/fixtures/v1.json
index 17b1df30..159334a3 100644
--- a/crates/tinysecurity-bus/tests/fixtures/v1.json
+++ b/crates/tinysecurity-bus/tests/fixtures/v1.json
@@ -590,7 +590,8 @@
     "ExecutionOutcome": [
       "succeeded",
       "failed",
-      "cancelled"
+      "cancelled",
+      "abandoned"
     ],
     "ReplyVerdict": [
       "allow_once",
diff --git a/crates/tinysecurity-bus/tests/scoped_wire.rs b/crates/tinysecurity-bus/tests/scoped_wire.rs
index a861de47..05a71266 100644
--- a/crates/tinysecurity-bus/tests/scoped_wire.rs
+++ b/crates/tinysecurity-bus/tests/scoped_wire.rs
@@ -1,4 +1,4 @@
-//! Registered subject policy wire shapes and the 1.29 compatibility boundary.
+//! Registered subject policy wire shapes and the contract compatibility boundary.
 use serde_json::json;
 use tinysecurity_bus::*;
 
@@ -87,11 +87,14 @@ fn new_members_are_advertised_and_named_by_contract_constants() {
 }
 
 #[test]
-fn contract_bump_is_additive_for_older_hosts_and_modules() {
-    assert_eq!(CONTRACT_VERSION, (1, 29));
-    // A host built against 1.29 accepts this module and newer minors, not a 1.28 module.
-    assert!(is_compatible((1, 29)));
+fn incompatible_execution_outcome_requires_a_new_contract_major() {
+    assert_eq!(CONTRACT_VERSION, (2, 0));
+    // A 2.0 host accepts compatible 2.x modules, but older 1.x hosts reject this module.
+    assert!(is_compatible((2, 0)));
+    assert!(is_compatible((2, 1)));
+    assert!(!is_compatible((1, 29)));
     assert!(!is_compatible((1, 28)));
+    assert!(!is_compatible((1, 27)));
     assert!(!is_compatible((1, 26)));
     assert!(!is_compatible((1, 25)));
     assert!(!is_compatible((1, 24)));
@@ -109,7 +112,6 @@ fn contract_bump_is_additive_for_older_hosts_and_modules() {
     // A 1.12 module cannot supply the audited scoped members.
     assert!(!is_compatible((1, 12)));
     assert!(!is_compatible((1, 11)));
-    assert!(!is_compatible((2, 0)));
 }
 
 #[test]
diff --git a/crates/tinysecurity-bus/tests/wire.rs b/crates/tinysecurity-bus/tests/wire.rs
index ac0a2e2f..ec594c44 100644
--- a/crates/tinysecurity-bus/tests/wire.rs
+++ b/crates/tinysecurity-bus/tests/wire.rs
@@ -114,6 +114,8 @@ fn all_execution_outcome_variants_have_stable_wire_names()
         assert_eq!(serde_json::to_value(decoded)?, *v);
     }
     assert!(serde_json::from_str::<ExecutionOutcome>("\"future_unknown\"").is_err());
+    let abandoned: ExecutionOutcome = serde_json::from_str("\"abandoned\"")?;
+    assert_eq!(serde_json::to_string(&abandoned)?, "\"abandoned\"");
     Ok(())
 }
 #[test]
@@ -343,7 +345,7 @@ fn redactor_init_is_additive_and_secrets_never_enter_public_info()
         serde_json::to_value(&config)?["redactor"]["secrets"][0],
         "literal-private"
     );
-    assert_eq!(CONTRACT_VERSION, (1, 29));
+    assert_eq!(CONTRACT_VERSION, (2, 0));
     for (mode, wire) in [
         (RedactMode::Text, "text"),
         (RedactMode::StructuredArguments, "structured_arguments"),
diff --git a/crates/tinysecurity-module/examples/secret_cipher_native_contract/fixture.rs b/crates/tinysecurity-module/examples/secret_cipher_native_contract/fixture.rs
index ade2c8b9..a297cf7c 100644
--- a/crates/tinysecurity-module/examples/secret_cipher_native_contract/fixture.rs
+++ b/crates/tinysecurity-module/examples/secret_cipher_native_contract/fixture.rs
@@ -2217,7 +2217,7 @@ pub(super) async fn run(
     let host = start_callbacks(&lifecycle, &state).await?;
     let config = configuration(&host, mode)?;
     let loaded = lifecycle.load_file_with_config(library, serde_json::to_value(&config)?);
-    if matches!(mode, 15 | 16) {
+    if matches!(mode, 14..=16) {
         reject_invalid_config(&lifecycle, &host, loaded).await?;
         task.abort();
         return Ok(());
@@ -2228,6 +2228,9 @@ pub(super) async fn run(
         .await?
         .ok_or("native module peer")?;
     *state.module.lock().map_err(|_| denied())? = Some(module.clone());
+    // Windows native callbacks can exceed the default five-second bus timeout
+    // while completing the approval and audit handshake. Keep the outer
+    // fixture deadline above the callbacks' serial budgets for every mode.
     let proxy = host
         .proxy(module.as_str(), names::OBJECT_PATH, names::INTERFACE)?
         // Let the module's own callback deadline settle pending work. In
@@ -2341,11 +2344,14 @@ async fn execute(
         completion_audit: audit(*sequence + 2),
     };
     *sequence += 3;
-    let response = proxy
+    // Execution can make three serial audit callbacks, each with the configured
+    // 10-second deadline. Keep the fixture's outer deadline above that budget.
+    let execute_proxy = proxy.clone().with_timeout(Duration::from_secs(35));
+    let response = execute_proxy
         .call_confidential(names::methods::EXECUTE_SECRET_CIPHER2, (&execute,))
         .await;
     assert!(
-        proxy
+        execute_proxy
             .call_confidential::<SecretCipherResponse2>(
                 names::methods::EXECUTE_SECRET_CIPHER2,
                 (&execute,)
diff --git a/crates/tinysecurity-module/src/adapter_tests.rs b/crates/tinysecurity-module/src/adapter_tests.rs
index df181651..cec9a611 100644
--- a/crates/tinysecurity-module/src/adapter_tests.rs
+++ b/crates/tinysecurity-module/src/adapter_tests.rs
@@ -1990,7 +1990,7 @@ async fn assert_invalid_sdk_reinitializations(
         setup(
             server.clone(),
             ModuleConfig {
-                contract_version: (2, 0),
+                contract_version: (3, 0),
                 ..Default::default()
             }
         )
diff --git a/crates/tinysecurity-policy/src/engine_tests.rs b/crates/tinysecurity-policy/src/engine_tests.rs
index 6f08d5d8..5b06b3ce 100644
--- a/crates/tinysecurity-policy/src/engine_tests.rs
+++ b/crates/tinysecurity-policy/src/engine_tests.rs
@@ -66,12 +66,12 @@ fn verdict(policy: &Policy, request: &EvaluateRequest) -> Result<Verdict> {
 }
 
 #[test]
-fn additive_contract_minor_accepts_an_older_same_major_host() {
+fn incompatible_contract_major_rejects_an_older_host() {
     let config = ModuleConfig {
-        contract_version: (1, 28),
+        contract_version: (1, 29),
         ..Default::default()
     };
-    assert!(Policy::new(config).is_ok());
+    assert!(Policy::new(config).is_err());
 }
 
 #[test]
diff --git a/crates/tinysecurity-policy/tests/policy.rs b/crates/tinysecurity-policy/tests/policy.rs
index a1b6eb2e..c2b3ca6b 100644
--- a/crates/tinysecurity-policy/tests/policy.rs
+++ b/crates/tinysecurity-policy/tests/policy.rs
@@ -67,7 +67,7 @@ fn failed_reinit_preserves_old_generation_and_configuration()
     let mut policy = Policy::new(ModuleConfig::default())?;
     let old = policy.info();
     let bad = ModuleConfig {
-        contract_version: (2, 0),
+        contract_version: (1, 29),
         ..Default::default()
     };
     assert_eq!(policy.reinitialize(bad), Err(Error::IncompatibleVersion));
diff --git a/docs/specs/approval-execution-outcomes.md b/docs/specs/approval-execution-outcomes.md
new file mode 100644
index 00000000..4ba42441
--- /dev/null
+++ b/docs/specs/approval-execution-outcomes.md
@@ -0,0 +1,12 @@
+# Approval execution outcomes
+
+Contract 2.0 adds `ExecutionOutcome::Abandoned` for an in-flight execution that
+was abandoned before the host could determine its effects. It is persisted as
+an immutable terminal outcome and does not claim that the tool had no effects.
+Use `Cancelled` only when the host has a definite cancelled result. A host that
+sees the legacy `aborted` value maps it to `Abandoned` because aborting a wait or
+task does not prove that execution had no effects.
+
+This closed enum change is a contract-major bump: a 1.x host cannot safely
+decode an `abandoned` result, so 1.x hosts reject a 2.x module during version
+compatibility checks.
diff --git a/docs/specs/security-module.md b/docs/specs/security-module.md
index 57485334..f76a0e07 100644
--- a/docs/specs/security-module.md
+++ b/docs/specs/security-module.md
@@ -152,6 +152,14 @@ Default TTL is ten minutes; copilot and sub-agent TTL is three minutes.
 permission. Cron external effects deny. SaaS has no implicit bypass: configure
 a verified per-user prompt channel or deny when human approval is needed.
 
+`ExecutionOutcome::Abandoned` records an in-flight execution that was abandoned
+before the host could determine its effects. This is not a cancellation and does
+not claim that the tool had no effects. Use `Cancelled` only for a definite
+cancelled result; map legacy `aborted` values to `Abandoned` because aborting a
+wait or task does not establish the execution's outcome. The `ExecutionOutcome`
+wire enum is closed, so this value requires contract 2.0: 1.x hosts must reject
+2.x providers rather than admit a provider whose result they cannot decode.
+
 Jev is an optional judge, disabled by default and enabled per origin. It can
 only convert `RequireApproval` to `Allow`; it cannot override any `Deny`, floor,
 privacy or sandbox requirement. Redacted input and independent questions test