diff --git a/acceptance/cmd/workspace/apps/run-local-node/script b/acceptance/cmd/workspace/apps/run-local-node/script
index 9749e979748..2bd2238c54b 100755
--- a/acceptance/cmd/workspace/apps/run-local-node/script
+++ b/acceptance/cmd/workspace/apps/run-local-node/script
@@ -2,8 +2,6 @@ cd app
 
 # Ports are allocated per run so that tests in parallel worktrees do not collide.
 read -r APP_PORT PROXY_PORT DEBUG_PORT PREPARE_PORT <<< "$(free_port.py 4)"
-add_repl "$PROXY_PORT" PROXY_PORT
-add_repl "$DEBUG_PORT" DEBUG_PORT
 
 # The app and the proxy start asynchronously; allow up to 15s for them to come up.
 export RETRY_MAX_ATTEMPTS=30
diff --git a/acceptance/cmd/workspace/apps/run-local-node/test.toml b/acceptance/cmd/workspace/apps/run-local-node/test.toml
index f46c1e68b26..de4fc763760 100644
--- a/acceptance/cmd/workspace/apps/run-local-node/test.toml
+++ b/acceptance/cmd/workspace/apps/run-local-node/test.toml
@@ -9,3 +9,17 @@ Ignore = [
 ]
 
 # The command is unrelated to bundle deployment, so run it once rather than per engine.
+
+# Ports are allocated per run. Mask them by context: a bare-number replacement would also hit
+# a matching run of digits inside the debugger's UUID and break its [UUID] masking.
+[[Repls]]
+Old = 'http://127\.0\.0\.1:\d+'
+New = 'http://127.0.0.1:[PROXY_PORT]'
+
+[[Repls]]
+Old = 'ws://127\.0\.0\.1:\d+'
+New = 'ws://127.0.0.1:[DEBUG_PORT]'
+
+[[Repls]]
+Old = 'attach a debugger to port \d+'
+New = 'attach a debugger to port [DEBUG_PORT]'
diff --git a/acceptance/cmd/workspace/apps/run-local/script b/acceptance/cmd/workspace/apps/run-local/script
index fd8b8b3c23e..f16f7db1d78 100755
--- a/acceptance/cmd/workspace/apps/run-local/script
+++ b/acceptance/cmd/workspace/apps/run-local/script
@@ -2,8 +2,6 @@ cd app
 
 # Ports are allocated per run so that tests in parallel worktrees do not collide.
 read -r APP_PORT PROXY_PORT ENTRY_POINT_PORT <<< "$(free_port.py 3)"
-add_repl "$APP_PORT" APP_PORT
-add_repl "$PROXY_PORT" PROXY_PORT
 
 # The app and the proxy start asynchronously; allow up to 15s for them to come up.
 export RETRY_MAX_ATTEMPTS=30
diff --git a/acceptance/cmd/workspace/apps/run-local/test.toml b/acceptance/cmd/workspace/apps/run-local/test.toml
index 43720d22644..cc57c18eb4b 100644
--- a/acceptance/cmd/workspace/apps/run-local/test.toml
+++ b/acceptance/cmd/workspace/apps/run-local/test.toml
@@ -3,7 +3,15 @@ RecordRequests = false
 
 # The command is unrelated to bundle deployment, so run it once rather than per engine.
 
-# The ports are registered as replacements by the script, which is where they are allocated.
+# Ports are allocated per run. Mask them by context: a bare-number replacement would also hit
+# a matching run of digits inside the X-Request-Id UUID and break its [UUID] masking.
+[[Repls]]
+Old = 'http://(127\.0\.0\.1|localhost):\d+'
+New = 'http://$1:[PROXY_PORT]'
+
+[[Repls]]
+Old = '"Host": "127\.0\.0\.1:\d+"'
+New = '"Host": "127.0.0.1:[APP_PORT]"'
 
 [[Repls]]
 Old='curl/[0-9]+\.[0-9]+\.[0-9]+'