diff --git a/claude_bottle/backend/docker/launch.py b/claude_bottle/backend/docker/launch.py
index dc98195..f8e559c 100644
--- a/claude_bottle/backend/docker/launch.py
+++ b/claude_bottle/backend/docker/launch.py
@@ -278,7 +278,7 @@ def _run_agent_container(plan: DockerBottlePlan, internal_network: str) -> str:
         docker_args.extend(["-e", name])
 
     # PRD 0013: read-only current-config mount so the agent can read
-    # routes.json / allowlist / Dockerfile before composing a
+    # routes.yaml / allowlist / Dockerfile before composing a
     # supervise tool-call proposal. Mounted from the per-bottle
     # stage_dir/current-config/ populated at prepare time.
     if plan.supervise_plan is not None:
diff --git a/claude_bottle/supervise.py b/claude_bottle/supervise.py
index 08a05ab..dbf37c4 100644
--- a/claude_bottle/supervise.py
+++ b/claude_bottle/supervise.py
@@ -425,7 +425,13 @@ def sha256_hex(content: str) -> str:
 # Filenames inside the per-bottle current-config dir. The agent reads
 # these (read-only) from CURRENT_CONFIG_DIR_IN_AGENT and proposes
 # modified versions back via the three MCP tools.
-CURRENT_CONFIG_ROUTES = "routes.json"
+# Filename of the staged egress-proxy routes file inside the agent's
+# read-only current-config mount. JSON content under a `.yaml`
+# extension to match the live file the egress-proxy sidecar reads
+# (`/etc/egress-proxy/routes.yaml`) — the egress-proxy-block tool
+# description points at this exact path, and the apply step writes
+# the new content to the matching live path.
+CURRENT_CONFIG_ROUTES = "routes.yaml"
 CURRENT_CONFIG_ALLOWLIST = "allowlist"
 CURRENT_CONFIG_DOCKERFILE = "Dockerfile"
 
@@ -437,7 +443,7 @@ class SupervisePlan:
     `queue_dir` is the host directory bind-mounted into the sidecar
     at /run/supervise/queue. `current_config_dir` is the host
     directory bind-mounted (read-only) into the *agent* container at
-    /etc/claude-bottle/current-config, holding routes.json + allowlist
+    /etc/claude-bottle/current-config, holding routes.yaml + allowlist
     + Dockerfile so the agent can read them before composing a
     proposal. `internal_network` is empty at prepare time; the
     backend's launch step fills it via dataclasses.replace before
diff --git a/tests/unit/test_dashboard.py b/tests/unit/test_dashboard.py
index 80e8c24..39ce94a 100644
--- a/tests/unit/test_dashboard.py
+++ b/tests/unit/test_dashboard.py
@@ -38,7 +38,7 @@ FIXED = datetime(2026, 5, 25, 12, 0, 0, tzinfo=timezone.utc)
 
 
 def _proposal(slug: str = "dev", tool: str = TOOL_EGRESS_PROXY_BLOCK) -> Proposal:
-    # Per-tool payload shape: cred-proxy gets routes.json, pipelock
+    # Per-tool payload shape: cred-proxy gets routes.yaml, pipelock
     # gets a failed URL (PR #25 follow-up), capability gets a
     # Dockerfile-ish blob. Match the production dispatch in
     # PROPOSED_FILE_FIELD.
diff --git a/tests/unit/test_supervise.py b/tests/unit/test_supervise.py
index f24baa2..9e18c70 100644
--- a/tests/unit/test_supervise.py
+++ b/tests/unit/test_supervise.py
@@ -297,9 +297,9 @@ class TestDiffAndHash(unittest.TestCase):
         self.assertEqual("", render_diff("a\nb\n", "a\nb\n"))
 
     def test_render_diff_shows_changes(self):
-        diff = render_diff("a\nb\nc\n", "a\nB\nc\n", label="routes.json")
-        self.assertIn("routes.json (current)", diff)
-        self.assertIn("routes.json (proposed)", diff)
+        diff = render_diff("a\nb\nc\n", "a\nB\nc\n", label="routes.yaml")
+        self.assertIn("routes.yaml (current)", diff)
+        self.assertIn("routes.yaml (proposed)", diff)
         self.assertIn("-b", diff)
         self.assertIn("+B", diff)
 
@@ -365,7 +365,7 @@ class TestSupervisePrepare(unittest.TestCase):
         self.assertTrue(plan.current_config_dir.is_dir())
         self.assertEqual(
             '{"routes": [{"path": "/x/"}]}\n',
-            (plan.current_config_dir / "routes.json").read_text(),
+            (plan.current_config_dir / "routes.yaml").read_text(),
         )
         self.assertEqual(
             "example.com\n",
@@ -382,7 +382,7 @@ class TestSupervisePrepare(unittest.TestCase):
         plan = _StubSupervise().prepare("dev", self.stage_dir)
         self.assertEqual(
             '{"routes": []}\n',
-            (plan.current_config_dir / "routes.json").read_text(),
+            (plan.current_config_dir / "routes.yaml").read_text(),
         )