diff --git a/Cargo.lock b/Cargo.lock
index d19a0716..43ef6f13 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -509,7 +509,7 @@ checksum = "c8d4a3bb8b1e0c1050499d1815f5ab16d04f0959b233085fb31653fbfc9d98f9"
 
 [[package]]
 name = "cli-sub-agent"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "chrono",
@@ -701,7 +701,7 @@ dependencies = [
 
 [[package]]
 name = "csa-acp"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "agent-client-protocol",
  "anyhow",
@@ -721,7 +721,7 @@ dependencies = [
 
 [[package]]
 name = "csa-config"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "chrono",
@@ -739,7 +739,7 @@ dependencies = [
 
 [[package]]
 name = "csa-core"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "agent-teams",
  "chrono",
@@ -755,7 +755,7 @@ dependencies = [
 
 [[package]]
 name = "csa-eval"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "chrono",
@@ -769,7 +769,7 @@ dependencies = [
 
 [[package]]
 name = "csa-executor"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "agent-teams",
  "anyhow",
@@ -797,7 +797,7 @@ dependencies = [
 
 [[package]]
 name = "csa-hooks"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "chrono",
@@ -816,7 +816,7 @@ dependencies = [
 
 [[package]]
 name = "csa-lock"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "chrono",
@@ -830,7 +830,7 @@ dependencies = [
 
 [[package]]
 name = "csa-mcp-hub"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "axum",
@@ -853,7 +853,7 @@ dependencies = [
 
 [[package]]
 name = "csa-memory"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -872,7 +872,7 @@ dependencies = [
 
 [[package]]
 name = "csa-process"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "chrono",
@@ -891,7 +891,7 @@ dependencies = [
 
 [[package]]
 name = "csa-resource"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "csa-core",
@@ -907,7 +907,7 @@ dependencies = [
 
 [[package]]
 name = "csa-scheduler"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "chrono",
@@ -925,7 +925,7 @@ dependencies = [
 
 [[package]]
 name = "csa-session"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "chrono",
@@ -951,7 +951,7 @@ dependencies = [
 
 [[package]]
 name = "csa-todo"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "chrono",
@@ -4516,7 +4516,7 @@ dependencies = [
 
 [[package]]
 name = "weave"
-version = "0.1.733"
+version = "0.1.734"
 dependencies = [
  "anyhow",
  "clap",
diff --git a/Cargo.toml b/Cargo.toml
index f942c814..a628703f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,7 +20,7 @@ default-members = [
 resolver = "2"
 
 [workspace.package]
-version = "0.1.733"
+version = "0.1.734"
 edition = "2024"
 rust-version = "1.88"
 license = "Apache-2.0"
diff --git a/crates/cli-sub-agent/src/run_cmd_attempt_support.rs b/crates/cli-sub-agent/src/run_cmd_attempt_support.rs
index c2a1d861..13acb1fe 100644
--- a/crates/cli-sub-agent/src/run_cmd_attempt_support.rs
+++ b/crates/cli-sub-agent/src/run_cmd_attempt_support.rs
@@ -7,16 +7,19 @@ use crate::pipeline;
 
 pub(crate) fn allow_cross_tool_failover(
     strategy: ToolSelectionStrategy,
-    resolved_tier_name: Option<&str>,
-    force_ignore_tier_setting: bool,
+    _resolved_tier_name: Option<&str>,
+    _force_ignore_tier_setting: bool,
     no_failover: bool,
 ) -> bool {
     if no_failover {
         return false;
     }
 
+    // Explicit `--tool` (from CLI or skill agent_config) is the user's hard
+    // selection: never silently fall over to a different tool, even when a
+    // tier is also specified (#1440). Tier still drives model selection for
+    // the chosen tool via `resolve_requested_tool_from_tier`.
     !matches!(strategy, ToolSelectionStrategy::Explicit(_))
-        || (!force_ignore_tier_setting && resolved_tier_name.is_some())
 }
 
 pub(crate) fn resolve_attempt_initial_response_timeout_seconds(
diff --git a/crates/cli-sub-agent/src/run_cmd_attempt_tests.rs b/crates/cli-sub-agent/src/run_cmd_attempt_tests.rs
index d08d8905..125a52a2 100644
--- a/crates/cli-sub-agent/src/run_cmd_attempt_tests.rs
+++ b/crates/cli-sub-agent/src/run_cmd_attempt_tests.rs
@@ -595,13 +595,15 @@ fn explicit_tool_no_failover_blocks_cross_tool_failover() {
     ));
 }
 
+// Regression #1440: explicit `--tool` blocks cross-tool failover even with `--tier`.
 #[test]
-fn explicit_tool_in_tier_keeps_cross_tool_failover_available() {
-    assert!(allow_cross_tool_failover(
-        ToolSelectionStrategy::Explicit(ToolName::Codex),
-        Some("tier-3-complex"),
-        false,
+fn explicit_tool_in_tier_blocks_cross_tool_failover() {
+    let strategy = ToolSelectionStrategy::Explicit(ToolName::ClaudeCode);
+    assert!(!allow_cross_tool_failover(
+        strategy,
+        Some("t4"),
         false,
+        false
     ));
 }