diff --git a/environments/compact/compact/program.py b/environments/compact/compact/program.py
index c9d3736daa..610992cab0 100644
--- a/environments/compact/compact/program.py
+++ b/environments/compact/compact/program.py
@@ -1,6 +1,6 @@
 # /// script
 # requires-python = ">=3.10"
-# dependencies = ["openai", "mcp"]
+# dependencies = ["openai", "mcp>=1.24.0,<2"]
 # ///
 """The compacting harness's program: a context-REWRITE loop (so every turn branches).
 
diff --git a/verifiers/v1/harnesses/bash/program.py b/verifiers/v1/harnesses/bash/program.py
index aa9326c806..c2b71a7183 100644
--- a/verifiers/v1/harnesses/bash/program.py
+++ b/verifiers/v1/harnesses/bash/program.py
@@ -1,6 +1,6 @@
 # /// script
 # requires-python = ">=3.10"
-# dependencies = ["openai", "mcp", "httpx", "tenacity"]
+# dependencies = ["openai", "mcp>=1.24.0,<2", "httpx", "tenacity"]
 # ///
 """Secrets arrive through argv so local tool subprocesses do not inherit them."""
 
diff --git a/verifiers/v1/harnesses/null/program.py b/verifiers/v1/harnesses/null/program.py
index 189f55633a..b17b619a1f 100644
--- a/verifiers/v1/harnesses/null/program.py
+++ b/verifiers/v1/harnesses/null/program.py
@@ -1,6 +1,6 @@
 # /// script
 # requires-python = ">=3.11"
-# dependencies = ["openai", "mcp", "httpx", "tenacity"]
+# dependencies = ["openai", "mcp>=1.24.0,<2", "httpx", "tenacity"]
 # ///
 """The interception endpoint and secret arrive through argv rather than the environment."""
 
diff --git a/verifiers/v1/harnesses/rlm/harness.py b/verifiers/v1/harnesses/rlm/harness.py
index 9bc4194301..8e9b47339f 100644
--- a/verifiers/v1/harnesses/rlm/harness.py
+++ b/verifiers/v1/harnesses/rlm/harness.py
@@ -94,6 +94,8 @@ async def setup(self, runtime: Runtime) -> None:
         ensure = shlex.quote(f"[ -x {RLM_BIN} ] || ({install})")
         guarded = f"mkdir -p {RLM_DIR} && flock {RLM_DIR}/install.lock sh -c {ensure}"
         env = {**self.config.resolved_env, "RLM_HOME": RLM_HOME}
+        extra_uv_args = env.get("RLM_EXTRA_UV_ARGS", "")
+        env["RLM_EXTRA_UV_ARGS"] = f"{extra_uv_args} --with mcp~=1.28".strip()
         result = await runtime.run(["sh", "-c", guarded], env)
         if result.exit_code != 0:
             raise RuntimeError(f"rlm install failed: {result.stderr.strip()[-500:]}")