diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 028b25f9..8abdfd80 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,9 +8,9 @@ on:
 
 # The `test` job runs the unit suites only. The integration suites gated on
 # `ORCA_INTEGRATION=1` need an authenticated `claude`/`gh` and stay skipped —
-# except `BuiltInFlowsCompileTest`, which needs only scala-cli and gets its own
-# `flow-scripts` job, with the env var scoped to that one `testOnly`. Run the
-# rest locally with `ORCA_INTEGRATION=1 sbt testFull`.
+# except `BuiltInFlowsCompileTest` and `CompileProbeTest`, which need only
+# scala-cli and get their own `flow-scripts` job, with the env var scoped to
+# that one `testOnly`. Run the rest locally with `ORCA_INTEGRATION=1 sbt testFull`.
 #
 # Publish runs inline (rather than reusing
 # softwaremill/github-actions-workflows) because `secrets: inherit` only
@@ -60,7 +60,7 @@ jobs:
       - uses: sbt/setup-sbt@v1
       - uses: coursier/cache-action@v6
       - run: |
-          sbt "publishLocal ; shell/testOnly *BuiltInFlowsCompileTest" | tee sbt.log
+          sbt "publishLocal ; shell/testOnly *BuiltInFlowsCompileTest *CompileProbeTest" | tee sbt.log
           if grep "Couldn't resolve a member" sbt.log; then
             echo "::error::Unresolved scaladoc link(s), see above"
             exit 1
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 14aaee75..c4433b56 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -53,15 +53,16 @@ the tests won't see `ORCA_INTEGRATION=1`.
 | `OsGitHubIntegrationTest` | `gh` authenticated |
 | `BuiltInFlowsCompileTest`, `FlowAuthoringSmokeTest` | `scala-cli`, and a `publishLocal` in the same sbt invocation |
 | `ScalaCliSmokeTest` | the above, plus `claude` authenticated — it starts a real flow |
+| `CompileProbeTest` | `scala-cli` |
 
-The three scala-cli suites link a script against the local Ivy cache, so they
+The other three scala-cli suites link a script against the local Ivy cache, so they
 need `publishLocal` in the *same* sbt invocation: the scripts pin that run's
 dynver version (runner's suite reads it from `-Dorca.build.version`, shell's
 from the version resource the build generates).
 
-`BuiltInFlowsCompileTest` is the only one CI runs (its own `flow-scripts` job),
-being the only one needing no credentials. It compiles every built-in flow as
-`BuiltInFlows` stages them for a snapshot build — pin rewritten to the
+CI runs `BuiltInFlowsCompileTest` and `CompileProbeTest` in its own
+`flow-scripts` job. The former compiles
+every built-in flow as `BuiltInFlows` stages them for a snapshot build — pin rewritten to the
 just-published version, `//> using repository ivy2Local` inserted — so an API change that
 breaks the flows fails CI instead of shipping. On a release version there is no
 rewrite (the flows resolve from Maven Central), so it skips itself.
diff --git a/shell/src/main/scala/orca/shell/run/FlowLauncher.scala b/shell/src/main/scala/orca/shell/run/FlowLauncher.scala
index bc05394f..e38fe1d0 100644
--- a/shell/src/main/scala/orca/shell/run/FlowLauncher.scala
+++ b/shell/src/main/scala/orca/shell/run/FlowLauncher.scala
@@ -70,10 +70,7 @@ private[shell] object FlowLauncher:
   private def depArgs(forced: Option[OrcaBuild]): Seq[String] =
     forced.toSeq.flatMap(_.forceArgs)
 
-  /** Tells the flow child its [[FlowSource]] ([[FlowSourceProperty]]). On the
-    * compile probe too, since scala-cli rebuilds when a `--java-prop` value
-    * changes.
-    */
+  /** Tells the flow child its [[FlowSource]] ([[FlowSourceProperty]]). */
   private def flowSourceArgs(source: FlowSource): Seq[String] =
     Seq("--java-prop", FlowSourceProperty.assignment(source))
 
@@ -110,7 +107,8 @@ private[shell] object FlowLauncher:
 
   /** The compile probe's argv — same `--workspace` treatment as [[argv]], and
     * for the same reason: without it, the probe (run whenever the forced
-    * version fails) would write its own `.scala-build` next to `flow` too.
+    * version fails) would write its own `.scala-build` next to `flow` too. No
+    * [[flowSourceArgs]]: `scala-cli compile` rejects `--java-prop`.
     */
   private[run] def compileArgv(
       flow: LaunchedFlow,
@@ -121,8 +119,7 @@ private[shell] object FlowLauncher:
       "scala-cli",
       "compile",
       flow.path.toString
-    ) ++ forced.forceArgs ++ flowSourceArgs(flow.source) ++
-      Seq("--workspace", workspaceDir.toString)
+    ) ++ forced.forceArgs ++ Seq("--workspace", workspaceDir.toString)
 
   /** What to do once the forced run has finished. */
   enum NextAction:
diff --git a/shell/src/test/scala/orca/shell/run/CompileProbeTest.scala b/shell/src/test/scala/orca/shell/run/CompileProbeTest.scala
new file mode 100644
index 00000000..0db25c9a
--- /dev/null
+++ b/shell/src/test/scala/orca/shell/run/CompileProbeTest.scala
@@ -0,0 +1,32 @@
+package orca.shell.run
+
+import orca.progress.FlowSource
+import orca.shell.OrcaBuild
+import orca.testkit.TempDirs
+
+/** Runs [[FlowLauncher.compileArgv]] through a real `scala-cli`, so a flag
+  * `scala-cli compile` rejects fails here instead of turning every flow failure
+  * into a version-pin fallback offer. Pins a published release, so no
+  * `publishLocal` is needed. Gated on `ORCA_INTEGRATION` (network + a real
+  * scala-cli on PATH); skipped otherwise.
+  */
+class CompileProbeTest extends munit.FunSuite:
+
+  override def munitTests(): Seq[Test] =
+    if sys.env.contains("ORCA_INTEGRATION") then super.munitTests()
+    else Nil
+
+  override def munitTimeout: scala.concurrent.duration.Duration =
+    import scala.concurrent.duration.DurationInt
+    5.minutes
+
+  test("compileArgv compiles a valid flow"):
+    val dir = TempDirs.dir()
+    val script = dir / "flow.sc"
+    os.write(script, "println(\"ok\")\n")
+    val flow = LaunchedFlow(script, FlowSource.Catalog("flow.sc"))
+    val argv =
+      FlowLauncher.compileArgv(flow, OrcaBuild.Release("0.2.1"), dir)
+    val result =
+      os.proc(argv).call(cwd = dir, check = false, mergeErrIntoOut = true)
+    assertEquals(result.exitCode, 0, result.out.text())
diff --git a/shell/src/test/scala/orca/shell/run/FlowLauncherTest.scala b/shell/src/test/scala/orca/shell/run/FlowLauncherTest.scala
index c5d8be90..5de3ffe3 100644
--- a/shell/src/test/scala/orca/shell/run/FlowLauncherTest.scala
+++ b/shell/src/test/scala/orca/shell/run/FlowLauncherTest.scala
@@ -119,12 +119,6 @@ class FlowLauncherTest extends munit.FunSuite:
       )
     )
 
-  test("compileArgv passes the same flow source as argv"):
-    // scala-cli rebuilds when a --java-prop value changes.
-    val compile =
-      FlowLauncher.compileArgv(flow, OrcaBuild.Release("0.0.18"), workspaceDir)
-    assert(compile.containsSlice(Seq("--java-prop", sourceProp)), compile)
-
   test("resolveNextAction: a zero exit is Succeed, without the compile probe"):
     val probeCalls = new java.util.concurrent.atomic.AtomicInteger(0)
     val result =