chore: import upstream snapshot with attribution

examples/stories/mrtr/client.py

@@ -0,0 +1,70 @@
+"""Drive the deploy tool both ways: the Client auto-loop, and a manual session-level loop."""
+
+import mcp_types as types
+
+from mcp import MCPError
+from mcp.client import Client, ClientRequestContext
+from stories._harness import Target, run_client
+
+
+async def on_elicit(context: ClientRequestContext, params: types.ElicitRequestParams) -> types.ElicitResult:
+    # The same callback serves legacy push-style elicitation/create requests AND embedded
+    # InputRequiredResult.input_requests entries — the driver dispatches both here.
+    assert isinstance(params, types.ElicitRequestFormParams)
+    assert "confirm" in params.requested_schema["properties"]
+    return types.ElicitResult(action="accept", content={"confirm": True})
+
+
+async def main(target: Target, *, mode: str = "auto") -> None:
+    async with Client(target, mode=mode, elicitation_callback=on_elicit) as client:
+        # ── auto-loop: Client.call_tool dispatches input_requests to on_elicit and retries
+        # internally; the caller just sees the final CallToolResult.
+        deployed = await client.call_tool("deploy", {"env": "production"})
+        assert isinstance(deployed.content[0], types.TextContent)
+        assert deployed.content[0].text == "deployed to production", deployed
+
+        # ── manual loop: drop to client.session for the raw InputRequiredResult so the
+        # request_state can be persisted between rounds (e.g. across a process restart).
+        first = await client.session.call_tool("deploy", {"env": "staging"}, allow_input_required=True)
+        assert isinstance(first, types.InputRequiredResult)
+        assert first.input_requests is not None and "confirm" in first.input_requests
+        # The boundary sealed server.py's plaintext "awaiting-confirm"; the wire token is opaque.
+        token = first.request_state
+        assert token is not None and token != "awaiting-confirm", token
+
+        responses: types.InputResponses = {"confirm": types.ElicitResult(action="decline")}
+
+        # Tamper demo: flipping any one character fails verification, and every failure
+        # maps to one frozen wire error; the real reason appears only in the server log.
+        i = len(token) // 2
+        tampered = token[:i] + ("A" if token[i] != "A" else "B") + token[i + 1 :]
+        try:
+            await client.session.call_tool(
+                "deploy",
+                {"env": "staging"},
+                input_responses=responses,
+                request_state=tampered,
+                allow_input_required=True,
+            )
+        except MCPError as e:
+            assert e.code == types.INVALID_PARAMS
+            assert e.message == "Invalid or expired requestState"
+            assert e.data == {"reason": "invalid_request_state"}
+        else:
+            raise AssertionError("expected MCPError for a tampered requestState")
+
+        # The untampered token still completes the round; decline so this path diverges from the auto run.
+        second = await client.session.call_tool(
+            "deploy",
+            {"env": "staging"},
+            input_responses=responses,
+            request_state=token,
+            allow_input_required=True,
+        )
+        assert isinstance(second, types.CallToolResult)
+        assert isinstance(second.content[0], types.TextContent)
+        assert second.content[0].text == "deployment to staging cancelled", second
+
+
+if __name__ == "__main__":
+    run_client(main)