diff --git a/docs/plans/2026-05-11-add-fabro-mcp-server-test-plan.md b/docs/plans/2026-05-11-add-fabro-mcp-server-test-plan.md
index d90a41459..ee9224c99 100644
--- a/docs/plans/2026-05-11-add-fabro-mcp-server-test-plan.md
+++ b/docs/plans/2026-05-11-add-fabro-mcp-server-test-plan.md
@@ -273,7 +273,7 @@ Covered action space:
 
 - CLI executable commands: `fabro mcp --help`, `fabro mcp start --help`, `fabro mcp config --help`, `fabro mcp init --help`, `fabro mcp config`, `fabro mcp config --server --storage-dir`, and `fabro mcp init claude|cursor|windsurf`.
 - MCP protocol actions: stdio process startup, `initialize`, `tools/list`, and `tools/call`.
-- MCP tool actions: `fabro_run_create`; `fabro_run_search`; `fabro_run_interact` actions `get`, `start`, `message`, `cancel`, `archive`, `unarchive`, `get_questions`, `answer`; `fabro_run_gather`; `fabro_run_events` actions `list`, `details`, and `search`.
+- MCP tool actions: `fabro_run_create`; `fabro_run_search`; `fabro_run_interact` actions `get`, `start`, `message`, `interrupt`, `cancel`, `archive`, `unarchive`, `get_questions`, `answer`; `fabro_run_gather`; `fabro_run_events` actions `list`, `details`, and `search`.
 - Error and boundary behavior: invalid local parameters, too many run ids, null input conversion, missing action fields, unsupported answer shapes, invalid agent config JSON, missing auth, unreachable server after local validation, timeout expiry, and service liveness after tool errors.
 - Integration boundaries: CLI auth store reuse, Fabro API client, real local Fabro server, run manifest construction/validation, event store, generated API answer types, and existing `fabro-mcp` client crate.
 - Performance smoke: initialize plus `tools/list` without auth/server.
diff --git a/lib/crates/fabro-cli/tests/it/cmd/mcp.rs b/lib/crates/fabro-cli/tests/it/cmd/mcp.rs
index 358372879..332af03e8 100644
--- a/lib/crates/fabro-cli/tests/it/cmd/mcp.rs
+++ b/lib/crates/fabro-cli/tests/it/cmd/mcp.rs
@@ -1369,6 +1369,11 @@ async fn mcp_interact_actions_resolve_selector_and_call_expected_endpoints() {
             .json_body(serde_json::json!({ "text": "continue", "interrupt": true }));
         then.status(202);
     });
+    let interrupt = server.mock(|when, then| {
+        when.method(POST)
+            .path(format!("/api/v1/runs/{run_id}/interrupt"));
+        then.status(202);
+    });
     let cancel = server.mock(|when, then| {
         when.method(POST)
             .path(format!("/api/v1/runs/{run_id}/cancel"));
@@ -1408,6 +1413,12 @@ async fn mcp_interact_actions_resolve_selector_and_call_expected_endpoints() {
         }),
     )
     .await;
+    let interrupt_result = call_tool_json(
+        &client,
+        "fabro_run_interact",
+        serde_json::json!({ "run_id": selector, "action": "interrupt" }),
+    )
+    .await;
     let cancel_result = call_tool_json(
         &client,
         "fabro_run_interact",
@@ -1419,12 +1430,14 @@ async fn mcp_interact_actions_resolve_selector_and_call_expected_endpoints() {
     assert_eq!(start_result["result"]["summary"]["run_id"], run_id);
     assert_eq!(message_result["result"]["message"], "continue");
     assert_eq!(message_result["result"]["interrupt"], true);
+    assert_eq!(interrupt_result["result"]["interrupted"], true);
     assert_eq!(cancel_result["result"]["summary"]["run_id"], run_id);
-    resolve.assert_calls(4);
+    resolve.assert_calls(5);
     retrieve.assert_calls(1);
     projection.assert();
     start.assert();
     message.assert();
+    interrupt.assert();
     cancel.assert();
     client
         .shutdown()
diff --git a/lib/crates/fabro-mcp-server/src/run_tools/interact.rs b/lib/crates/fabro-mcp-server/src/run_tools/interact.rs
index abd6b6cf7..28542abd2 100644
--- a/lib/crates/fabro-mcp-server/src/run_tools/interact.rs
+++ b/lib/crates/fabro-mcp-server/src/run_tools/interact.rs
@@ -17,6 +17,11 @@ pub(crate) enum RunInteractAction {
     Get,
     Start,
     Message,
+    /// Cancel the active API-mode agent's current LLM round and park it
+    /// waiting for a later `message`. The run sits idle until you follow up
+    /// with `message` or `cancel`. To redirect the agent, prefer `message`
+    /// (optionally with `interrupt: true`).
+    Interrupt,
     Cancel,
     Archive,
     Unarchive,
@@ -111,6 +116,7 @@ pub(crate) enum ValidatedInteractAction {
         message:   String,
         interrupt: bool,
     },
+    Interrupt,
     Cancel,
     Archive,
     Unarchive,
@@ -127,6 +133,7 @@ impl ValidatedInteractAction {
             Self::Get => RunInteractAction::Get,
             Self::Start => RunInteractAction::Start,
             Self::Message { .. } => RunInteractAction::Message,
+            Self::Interrupt => RunInteractAction::Interrupt,
             Self::Cancel => RunInteractAction::Cancel,
             Self::Archive => RunInteractAction::Archive,
             Self::Unarchive => RunInteractAction::Unarchive,
@@ -160,6 +167,7 @@ impl TryFrom<FabroRunInteractParams> for ValidatedInteractRun {
                     interrupt: params.interrupt.unwrap_or(false),
                 }
             }
+            RunInteractAction::Interrupt => ValidatedInteractAction::Interrupt,
             RunInteractAction::Cancel => ValidatedInteractAction::Cancel,
             RunInteractAction::Archive => ValidatedInteractAction::Archive,
             RunInteractAction::Unarchive => ValidatedInteractAction::Unarchive,
@@ -224,6 +232,13 @@ pub(crate) async fn interact_run(
                 .map_err(|err| ToolError::from_anyhow(&err))?;
             json!({ "message": message, "interrupt": interrupt })
         }
+        ValidatedInteractAction::Interrupt => {
+            client
+                .interrupt_run(&run_id)
+                .await
+                .map_err(|err| ToolError::from_anyhow(&err))?;
+            json!({ "interrupted": true })
+        }
         ValidatedInteractAction::Cancel => {
             let summary = client
                 .cancel_run(&run_id)
@@ -396,4 +411,23 @@ mod tests {
 
         assert!(err.as_str().contains("option, options, text"));
     }
+
+    #[test]
+    fn interrupt_action_requires_only_run_id() {
+        let validated = ValidatedInteractRun::try_from(FabroRunInteractParams {
+            action:      RunInteractAction::Interrupt,
+            run_id:      "run_123".to_string(),
+            message:     None,
+            interrupt:   None,
+            question_id: None,
+            answer:      None,
+        })
+        .expect("interrupt should validate with only run_id");
+
+        assert_eq!(validated.run_id, "run_123");
+        assert!(matches!(
+            validated.action,
+            ValidatedInteractAction::Interrupt
+        ));
+    }
 }
diff --git a/lib/crates/fabro-mcp-server/src/server.rs b/lib/crates/fabro-mcp-server/src/server.rs
index e82b2e404..b44fb4803 100644
--- a/lib/crates/fabro-mcp-server/src/server.rs
+++ b/lib/crates/fabro-mcp-server/src/server.rs
@@ -93,7 +93,7 @@ impl FabroMcpServer {
 
     #[tool(
         name = "fabro_run_interact",
-        description = "Get, start, message, cancel, archive, unarchive, inspect questions, or answer a Fabro run."
+        description = "Get, start, message, interrupt, cancel, archive, unarchive, inspect questions, or answer a Fabro run."
     )]
     async fn fabro_run_interact(
         &self,