diff --git a/.github/workflows/branch-checks.yml b/.github/workflows/branch-checks.yml
index 72f8273c1a..7b0c77c8fd 100644
--- a/.github/workflows/branch-checks.yml
+++ b/.github/workflows/branch-checks.yml
@@ -164,8 +164,8 @@ jobs:
         run: |
           cargo clippy --workspace --all-targets -- -D warnings
           cargo clippy --manifest-path e2e/rust/Cargo.toml --all-targets -- -D warnings
-          cargo check --manifest-path examples/governance-interceptor/Cargo.toml --all-targets
-          cargo check --manifest-path examples/supervisor-middleware-content-guard/Cargo.toml --all-targets
+          cargo clippy --manifest-path examples/governance-interceptor/Cargo.toml --all-targets -- -D warnings
+          cargo clippy --manifest-path examples/supervisor-middleware-content-guard/Cargo.toml --all-targets -- -D warnings
 
       - name: Test
         env:
@@ -207,6 +207,11 @@ jobs:
             exit 1
           fi
 
+      - name: Verify Cargo lockfiles unchanged
+        run: |
+          tasks/scripts/check-cargo-lockfiles.sh
+          git diff --exit-code HEAD -- ':(glob)**/Cargo.lock'
+
   python:
     name: Python (${{ matrix.runner }})
     needs: pr_metadata
@@ -247,7 +252,6 @@ jobs:
         run: |
           bash tasks/scripts/test-gateway-pull-policy.sh
           bash tasks/scripts/test-gateway-config.sh
-
   go:
     name: Go SDK
     needs: pr_metadata
diff --git a/TESTING.md b/TESTING.md
index 5d9674dd06..aaad71aa41 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -46,6 +46,8 @@ Run Rust tests only:
 mise run test:rust     # cargo test --workspace
 ```
 
+Rust validation checks tracked Cargo lockfiles; run `mise run rust:lockfiles:check` to check them directly. If one is stale, refresh it with Cargo using its adjacent manifest, review the diff, and commit the update.
+
 ## Python Unit Tests
 
 Python unit tests use the `*_test.py` suffix convention (not `test_*` prefix)
diff --git a/architecture/build.md b/architecture/build.md
index 5f3b913e1b..d6ad9914a9 100644
--- a/architecture/build.md
+++ b/architecture/build.md
@@ -514,6 +514,9 @@ Published docs live in `docs/`, and Fern site configuration lives in `fern/`. Se
 
 ## Validation Expectations
 
+Rust CI rejects stale or modified Cargo lockfiles and runs Clippy for the
+workspace, E2E crate, and standalone examples.
+
 - Run `mise run pre-commit` before committing.
 - Run `mise run test` after code changes.
 - Run `mise run e2e` for sandbox, policy, driver, or deployment changes when the
diff --git a/tasks/ci.toml b/tasks/ci.toml
index cc4158448f..e2a388e6b1 100644
--- a/tasks/ci.toml
+++ b/tasks/ci.toml
@@ -54,6 +54,7 @@ description = "Run repository lint checks"
 depends = [
   "license:check",
   "rust:format:check",
+  "rust:lockfiles:check",
   "rust:lint",
   "python:format:check",
   "python:lint",
diff --git a/tasks/rust.toml b/tasks/rust.toml
index e62e22b3cf..e8c45fd54c 100644
--- a/tasks/rust.toml
+++ b/tasks/rust.toml
@@ -5,17 +5,24 @@
 
 ["rust:check"]
 description = "Check all Rust crates for errors"
+depends = ["rust:lockfiles:check"]
 run = "cargo check --workspace"
 run_windows = "powershell -NoProfile -ExecutionPolicy Bypass -File tasks/scripts/windows-msvc.ps1 check native"
 hide = true
 
+["rust:lockfiles:check"]
+description = "Verify all tracked Cargo lockfiles are current"
+run = "tasks/scripts/check-cargo-lockfiles.sh"
+hide = true
+
 ["rust:lint"]
 description = "Lint Rust code with Clippy (deny warnings)"
+depends = ["rust:lockfiles:check"]
 run = [
   "cargo clippy --workspace --all-targets -- -D warnings",
   "cargo clippy --manifest-path e2e/rust/Cargo.toml --all-targets -- -D warnings",
-  "cargo check --manifest-path examples/governance-interceptor/Cargo.toml --all-targets",
-  "cargo check --manifest-path examples/supervisor-middleware-content-guard/Cargo.toml --all-targets",
+  "cargo clippy --manifest-path examples/governance-interceptor/Cargo.toml --all-targets -- -D warnings",
+  "cargo clippy --manifest-path examples/supervisor-middleware-content-guard/Cargo.toml --all-targets -- -D warnings",
 ]
 run_windows = "powershell -NoProfile -ExecutionPolicy Bypass -File tasks/scripts/windows-msvc.ps1 lint native"
 hide = true
diff --git a/tasks/scripts/check-cargo-lockfiles.sh b/tasks/scripts/check-cargo-lockfiles.sh
new file mode 100755
index 0000000000..bd74d8d647
--- /dev/null
+++ b/tasks/scripts/check-cargo-lockfiles.sh
@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+set -euo pipefail
+
+check_lockfile() {
+  local lockfile="$1"
+  local manifest="${lockfile%Cargo.lock}Cargo.toml"
+
+  if [[ ! -f "$manifest" ]]; then
+    printf 'error: tracked lockfile %s has no adjacent Cargo.toml\n' "$lockfile" >&2
+    return 1
+  fi
+
+  printf 'Checking %s\n' "$lockfile"
+  if ! cargo metadata \
+    --locked \
+    --format-version 1 \
+    --manifest-path "$manifest" \
+    >/dev/null; then
+    printf 'error: validation failed for %s\n' "$lockfile" >&2
+    return 1
+  fi
+}
+
+main() {
+  local lockfile
+  local found=0
+  local failed=0
+
+  cd "$(git rev-parse --show-toplevel)"
+
+  # Policy: every tracked Cargo.lock represents an intentionally reproducible
+  # Cargo workspace and must resolve against its adjacent Cargo.toml. Manifests
+  # that intentionally do not own a lockfile are outside this check.
+  while IFS= read -r -d '' lockfile; do
+    found=1
+    check_lockfile "$lockfile" || failed=1
+  done < <(git ls-files -z -- ':(glob)**/Cargo.lock')
+
+  if [[ "$found" -eq 0 ]]; then
+    echo "error: no tracked Cargo.lock files found" >&2
+    return 1
+  fi
+
+  if [[ "$failed" -ne 0 ]]; then
+    echo "Resolve the reported errors. If a lockfile needs updating, refresh it with Cargo and commit the result." >&2
+  fi
+
+  return "$failed"
+}
+
+main "$@"
diff --git a/tasks/test.toml b/tasks/test.toml
index 0fa0bd8496..8c41e70025 100644
--- a/tasks/test.toml
+++ b/tasks/test.toml
@@ -78,6 +78,7 @@ run = "bash tasks/scripts/e2e-gpu-build-images.sh"
 
 ["test:rust"]
 description = "Run Rust tests"
+depends = ["rust:lockfiles:check"]
 env = { OPENSHELL_TELEMETRY_ENABLED = "false" }
 run = [
   # Run the workspace once without openshell-server so we can run that crate