From 841257c434788534d0e556ae0ae1d97b946b330f Mon Sep 17 00:00:00 2001
From: OmniRoute Ops <ops@nomenak.dev>
Date: Tue, 12 May 2026 10:13:36 +0000
Subject: [PATCH] fix(cliproxyapi): preserve bare metadata.user_id on
 Anthropic-shape bodies
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The post-#2165 strip removed `metadata` unconditionally. That throws away
the inbound `metadata.user_id` field that BYOK clients like Capy send
(stable per Capy user — `user_<base62>`). CPA's outbound cloak then
generates a fresh random UUID per call (cf. `internal/runtime/executor/
helps/cloak_utils.go::generateFakeUserID` in router-for-me/CLIProxyAPI),
so Anthropic sees a different `account_uuid` and `session_uuid` for every
call from the same BYOK user — no prompt-cache reuse, and the account
fails Anthropic's "real Claude Code account" recognition signal that
likely gates `^mcp_[^_]` rejection / "Extra usage required" 400s.

Pass through a bare `{user_id: <string>}` shape so a future CPA-side patch
can use the value as a deterministic seed for the cloaked
`user_<hex>_account_<uuid>_session_<uuid>` triplet. Strip metadata
entirely if Capy's SDK adds anything beyond `user_id` (`session_id`,
`client_info`, etc., which Anthropic rejects).

No client-visible change today — the change only becomes useful when CPA
honors the inbound user_id ; without that patch CPA continues to overwrite
with its random fake. The OmniRoute-side change is a no-op-on-its-own
prerequisite that costs nothing if CPA never adopts the cooperation.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 open-sse/executors/cliproxyapi.ts       | 22 ++++++++++++++-
 tests/unit/cliproxyapi-executor.test.ts | 37 +++++++++++++++++++++++--
 2 files changed, 56 insertions(+), 3 deletions(-)

diff --git a/open-sse/executors/cliproxyapi.ts b/open-sse/executors/cliproxyapi.ts
index 601d100e037c..7262735db9a5 100644
--- a/open-sse/executors/cliproxyapi.ts
+++ b/open-sse/executors/cliproxyapi.ts
@@ -236,7 +236,27 @@ export class CliproxyapiExecutor extends BaseExecutor {
       delete transformed.client_info;
       delete transformed.prompt_cache_key;
       delete transformed.safety_identifier;
-      delete transformed.metadata;
+
+      // Conditional metadata strip. Preserve a bare `{user_id: <string>}`
+      // shape so a CPA-side patch can use the inbound user_id as a
+      // deterministic seed for the cloaked Claude-Code-shaped user_id
+      // (current CPA generates a fresh random UUIDv4 per call → no
+      // Anthropic prompt-cache reuse across calls from the same BYOK
+      // user ; passing through a stable Capy `metadata.user_id` lets CPA
+      // derive a stable `account_uuid`/`session_uuid` triplet from it).
+      //
+      // Strip metadata entirely if it carries any field beyond `user_id`
+      // (Capy's SDK can add `session_id`, `client_info`, etc., which
+      // Anthropic rejects).
+      const md = transformed.metadata;
+      if (md && typeof md === "object") {
+        const mdRec = md as Record<string, unknown>;
+        const isBareUserId = typeof mdRec.user_id === "string" && Object.keys(mdRec).length === 1;
+        if (!isBareUserId) {
+          delete transformed.metadata;
+        }
+        // bare {user_id: <string>} shape : keep as-is.
+      }
 
       // Conditional thinking strip: preserve Anthropic-valid shapes
       // ({type:"enabled"|"disabled", budget_tokens:N}) that applyThinkingBudget
diff --git a/tests/unit/cliproxyapi-executor.test.ts b/tests/unit/cliproxyapi-executor.test.ts
index 0d65bf243134..0eac00bbfdf6 100644
--- a/tests/unit/cliproxyapi-executor.test.ts
+++ b/tests/unit/cliproxyapi-executor.test.ts
@@ -356,17 +356,50 @@ describe("CliproxyapiExecutor", () => {
       assert.equal(result.output_config, undefined);
     });
 
-    it("strips metadata", () => {
+    it("preserves bare metadata {user_id} as a CPA cloak-seed", () => {
       const exec = new CliproxyapiExecutor();
       const result = exec.transformRequest(
         "claude-opus-4-7",
-        anthropicBody({ metadata: { user_id: "abc" } }),
+        anthropicBody({ metadata: { user_id: "user_3DGta5gzamzAUr57ZYZEtmc6lHX" } }),
+        true,
+        {}
+      );
+      assert.deepEqual(result.metadata, {
+        user_id: "user_3DGta5gzamzAUr57ZYZEtmc6lHX",
+      });
+    });
+
+    it("strips metadata when it carries extras beyond user_id", () => {
+      const exec = new CliproxyapiExecutor();
+      const result = exec.transformRequest(
+        "claude-opus-4-7",
+        anthropicBody({
+          metadata: { user_id: "abc", session_id: "s1", client_info: { name: "Capy" } },
+        }),
         true,
         {}
       );
       assert.equal(result.metadata, undefined);
     });
 
+    it("strips metadata when user_id is missing or non-string", () => {
+      const exec = new CliproxyapiExecutor();
+      const result1 = exec.transformRequest(
+        "claude-opus-4-7",
+        anthropicBody({ metadata: { session_id: "s1" } }),
+        true,
+        {}
+      );
+      assert.equal(result1.metadata, undefined);
+      const result2 = exec.transformRequest(
+        "claude-opus-4-7",
+        anthropicBody({ metadata: { user_id: 42 } }),
+        true,
+        {}
+      );
+      assert.equal(result2.metadata, undefined);
+    });
+
     it("strips client_info", () => {
       const exec = new CliproxyapiExecutor();
       const result = exec.transformRequest(