feat: pass through zero data retention opt-in (CMD_ZDR) (#8)

Command Code exposes ZDR as x-cmd-zdr: 1, the same opt-in its CLI reads
from CMD_ZDR=1. Mirror it for plugin users and strip any caller-supplied
header when the opt-in is absent, so a session that never asked for ZDR
cannot emit the flag by accident. Applied on the strict Command Code host
only, never on a lookalike that merely shares the request path.

Author: JoshRob297

CHANGELOG.md

@@ -5,6 +5,16 @@ Format: [Keep a Changelog](https://keepachangelog.com/en/1.1.0/) - SemVer.
 
 ## [Unreleased]
 
+## [1.0.7] - 2026-10-31
+
+### Added
+- Zero data retention passthrough. With `CMD_ZDR=1` every request to
+  `api.commandcode.ai` carries `x-cmd-zdr: 1`, mirroring the Command Code CLI.
+  When the opt-in is absent, any caller-supplied `x-cmd-zdr` header is stripped
+  so a session that never asked for ZDR cannot emit the flag by accident. The
+  header is applied on the strict Command Code host only, never on a lookalike
+  that merely shares the request path.
+
 ## [1.0.6] - 2026-10-25
 
 ### Added

README.es.md

@@ -94,6 +94,18 @@ un request):
 - **Registro de reintentos** - persiste los reintentos de transporte solo de Command
   Code, para poder diagnosticar una caida upstream a posteriori.
 
+### Zero data retention (opt-in)
+
+Command Code expone ZDR como cabecera de peticion (`x-cmd-zdr: 1`), el mismo
+opt-in que su CLI lee de `CMD_ZDR=1`. El plugin lo replica:
+
+- `CMD_ZDR=1` - toda peticion a `api.commandcode.ai` lleva `x-cmd-zdr: 1`.
+- En cualquier otro caso - se elimina cualquier `x-cmd-zdr` enviada por el
+  cliente, para que una sesion sin opt-in no pueda emitir la cabecera por error.
+
+La cabecera solo se aplica en el host estricto de Command Code, nunca en un host
+parecido que solo comparta `/provider/v1/...` en la ruta.
+
 ### Telemetria de cuota
 
 - Herramienta `commandcode_quota` y comando `/commandcode-quota`: plan, estado,

README.md

@@ -89,6 +89,18 @@ request):
 - **Retry logger** - persists transport retries for Command Code only, so an
   upstream outage can be diagnosed after the fact.
 
+### Zero data retention (opt-in)
+
+Command Code exposes ZDR as a request header (`x-cmd-zdr: 1`), the same opt-in
+its CLI reads from `CMD_ZDR=1`. The plugin mirrors it:
+
+- `CMD_ZDR=1` - every request to `api.commandcode.ai` carries `x-cmd-zdr: 1`.
+- Otherwise - any caller-supplied `x-cmd-zdr` header is stripped, so a session
+  that never opted in cannot emit the flag by accident.
+
+The header is applied only on the strict Command Code host, never on a lookalike
+that merely shares `/provider/v1/...` in its path.
+
 ### Quota telemetry
 
 - Tool `commandcode_quota` and command `/commandcode-quota`: plan, status,

index.ts

@@ -4,4 +4,5 @@ export default plugin;
 export * from "./src/auth/resolver.ts";
 export * from "./src/client/api.ts";
 export * from "./src/hooks/resilience.ts";
+export * from "./src/hooks/zdr.ts";
 export * from "./src/tools/quota.ts";

package.json

@@ -1,6 +1,6 @@
 {
   "name": "opencode-commandcode",
-  "version": "1.0.6",
+  "version": "1.0.7",
   "description": "Production-grade OpenCode plugin for Command Code: dynamic model discovery, stability hooks and quota telemetry",
   "main": "index.ts",
   "type": "module",

src/hooks/zdr.ts

@@ -0,0 +1,40 @@
+/**
+ * Zero data retention (ZDR) passthrough.
+ *
+ * Command Code exposes ZDR as a request header (`x-cmd-zdr: 1`), the same
+ * opt-in its CLI reads from `CMD_ZDR=1`. The header is only emitted when the
+ * user explicitly opts in:
+ *
+ *   - `CMD_ZDR=1` -> every Command Code request carries `x-cmd-zdr: 1`
+ *   - anything else -> any caller-supplied `x-cmd-zdr` header is stripped, so
+ *     a session that did not opt in can never emit it by accident
+ *
+ * Stripping (instead of ignoring) matters because the header is a policy
+ * control: a lookalike client or a stale config must not be able to turn it on
+ * for a user who never asked for it.
+ */
+
+export const ZDR_HEADER = "x-cmd-zdr";
+
+/** True only for the explicit opt-in value documented by the CLI. */
+export function isZdrEnabled(env: Record<string, string | undefined> = process.env): boolean {
+  return env.CMD_ZDR === "1";
+}
+
+/**
+ * Applies the ZDR policy to a request's headers.
+ *
+ * Headers is case-insensitive, so `get`/`delete`/`set` cover every casing the
+ * caller may have used.
+ */
+export function applyZdrHeader(
+  headers: Headers,
+  env: Record<string, string | undefined> = process.env
+): void {
+  if (headers.get(ZDR_HEADER) !== null) {
+    headers.delete(ZDR_HEADER);
+  }
+  if (isZdrEnabled(env)) {
+    headers.set(ZDR_HEADER, "1");
+  }
+}

src/index.ts

@@ -13,6 +13,7 @@ import {
   supportsChatCompletions,
   supportsVision,
 } from "./hooks/resilience.ts";
+import { applyZdrHeader } from "./hooks/zdr.ts";
 import { getQuotaReport } from "./tools/quota.ts";
 import { describeRetryEvent } from "./telemetry.ts";
 import { buildReleaseDate, freeCostEntry } from "./catalog.ts";
@@ -166,7 +167,18 @@ export default {
           }
         }
 
-        // B. Credential injection, STRICT origin only (no lookalike hosts,
+        // B. Zero data retention policy (opt-in only, spoofed headers stripped).
+        //    Strict origin: the header is a Command Code policy flag and must
+        //    never be sent to a host that only happens to share the path.
+        if (isCommandCodeHost(url)) {
+          try {
+            applyZdrHeader(req.headers);
+          } catch {
+            // immutable headers in this runtime
+          }
+        }
+
+        // C. Credential injection, STRICT origin only (no lookalike hosts,
         //    no path-based matching: this is where the API key travels).
         if (isCommandCodeHost(url) && !req.headers.has("authorization")) {
           const key = resolveApiKey();
@@ -179,7 +191,7 @@ export default {
           }
         }
 
-        // C. Payload sanitizer (no credentials involved).
+        // D. Payload sanitizer (no credentials involved).
         try {
           const method = String(req.method || "GET").toUpperCase();
           if (method === "GET" || method === "HEAD") return;

tests/zdr.test.ts

@@ -0,0 +1,116 @@
+import { afterEach, beforeEach, describe, expect, test } from "bun:test";
+import plugin from "../src/index.ts";
+import { applyZdrHeader, isZdrEnabled, ZDR_HEADER } from "../src/hooks/zdr.ts";
+
+const URL_CC = "https://api.commandcode.ai/provider/v1/chat/completions";
+
+function makeCtx() {
+  const hooks: Record<string, ((event: any) => Promise<void>)[]> = {
+    "http.request": [],
+    "http.response": [],
+    retry: [],
+  };
+  const ctx: any = {
+    session: {
+      hook: async (name: any, cb: any) => {
+        hooks[name]?.push(cb);
+        return { dispose: async () => {} };
+      },
+      synthetic: async () => ({}),
+    },
+    model: { transform: async () => {} },
+    tool: { transform: async () => {} },
+    command: { transform: async () => {} },
+  };
+  return { ctx, hooks };
+}
+
+async function runHook(hooks: Record<string, ((event: any) => Promise<void>)[]>, request: Request) {
+  const event: any = { request, sessionID: "ses_test" };
+  for (const cb of hooks["http.request"] ?? []) {
+    await cb(event);
+  }
+  return event.request as Request;
+}
+
+describe("isZdrEnabled", () => {
+  test("only the documented opt-in value enables ZDR", () => {
+    expect(isZdrEnabled({ CMD_ZDR: "1" })).toBe(true);
+    expect(isZdrEnabled({ CMD_ZDR: "0" })).toBe(false);
+    expect(isZdrEnabled({ CMD_ZDR: "true" })).toBe(false);
+    expect(isZdrEnabled({})).toBe(false);
+  });
+});
+
+describe("applyZdrHeader", () => {
+  test("sets the header when opted in", () => {
+    const headers = new Headers();
+    applyZdrHeader(headers, { CMD_ZDR: "1" });
+    expect(headers.get(ZDR_HEADER)).toBe("1");
+  });
+
+  test("strips a caller-supplied header when not opted in", () => {
+    const headers = new Headers({ "x-cmd-zdr": "1" });
+    applyZdrHeader(headers, {});
+    expect(headers.get(ZDR_HEADER)).toBeNull();
+  });
+
+  test("strips any casing of the header when not opted in", () => {
+    const headers = new Headers({ "X-CMD-ZDR": "1" });
+    applyZdrHeader(headers, { CMD_ZDR: "0" });
+    expect(headers.get(ZDR_HEADER)).toBeNull();
+  });
+
+  test("keeps exactly one header value when opted in", () => {
+    const headers = new Headers();
+    headers.set("x-cmd-zdr", "0");
+    applyZdrHeader(headers, { CMD_ZDR: "1" });
+    expect(headers.get(ZDR_HEADER)).toBe("1");
+  });
+});
+
+describe("plugin ZDR hook", () => {
+  const previous = process.env.CMD_ZDR;
+
+  afterEach(() => {
+    if (previous === undefined) delete process.env.CMD_ZDR;
+    else process.env.CMD_ZDR = previous;
+  });
+
+  test("emits x-cmd-zdr on Command Code requests when CMD_ZDR=1", async () => {
+    process.env.CMD_ZDR = "1";
+    const { ctx, hooks } = makeCtx();
+    await plugin.setup(ctx);
+
+    const request = new Request(URL_CC, { method: "POST", body: "{}" });
+    const outgoing = await runHook(hooks, request);
+    expect(outgoing.headers.get(ZDR_HEADER)).toBe("1");
+  });
+
+  test("strips a spoofed header when CMD_ZDR is not set", async () => {
+    delete process.env.CMD_ZDR;
+    const { ctx, hooks } = makeCtx();
+    await plugin.setup(ctx);
+
+    const request = new Request(URL_CC, {
+      method: "POST",
+      body: "{}",
+      headers: { "x-cmd-zdr": "1" },
+    });
+    const outgoing = await runHook(hooks, request);
+    expect(outgoing.headers.get(ZDR_HEADER)).toBeNull();
+  });
+
+  test("never touches a lookalike host that only shares the path", async () => {
+    process.env.CMD_ZDR = "1";
+    const { ctx, hooks } = makeCtx();
+    await plugin.setup(ctx);
+
+    const request = new Request("https://api.commandcode.ai.evil.com/provider/v1/chat/completions", {
+      method: "POST",
+      body: "{}",
+    });
+    const outgoing = await runHook(hooks, request);
+    expect(outgoing.headers.get(ZDR_HEADER)).toBeNull();
+  });
+});