diff --git a/README.md b/README.md
index 0b923e940..e4c242c89 100644
--- a/README.md
+++ b/README.md
@@ -235,7 +235,7 @@ shows an **Output Tokens Saved** card next to input compression, labelled
 | Copilot CLI  | ✅              | starts proxy + launches          |
 | VS Code Copilot | ✅           | transparent proxy; preserves selected model |
 | OpenClaw     | ✅              | installs as ContextEngine plugin |
-| OpenCode     | ✅              | injects config · starts proxy + launches |
+| OpenCode     | ✅              | injects config · starts proxy + launches [^third-party-upstream] |
 | Cline        | ✅              | starts proxy + injects config    |
 | Continue     | ✅              | starts proxy + injects config    |
 | Goose        | ✅              | starts proxy + launches          |
@@ -246,6 +246,8 @@ shows an **Output Tokens Saved** card next to input compression, labelled
 | Kimi CLI     | ✅              | OAuth bearer forwarded — log in once |
 | ZCode        | ✅              | starts proxy and prints base URLs for ZCode settings |
 
+[^third-party-upstream]: `headroom wrap` routes OpenAI-compatible traffic to the default upstream (`https://api.openai.com/v1`). For a third-party OpenAI-compatible provider (DeepSeek, Together, OpenRouter, a self-hosted gateway), pass `--openai-api-url https://api.deepseek.com/v1` — or set `OPENAI_TARGET_API_URL` before wrapping — otherwise your provider key is sent to OpenAI and rejected with `401 Incorrect API key provided`. See [OpenCode + DeepSeek](docs/content/docs/opencode-deepseek.mdx).
+
 Any OpenAI-compatible client works via `headroom proxy`. MCP-native: `headroom mcp install`.
 Undo durable wrapping with `headroom unwrap <tool>` (supports: `claude`, `copilot`, `codex`, `grok`, `kimi`, `omp`, `opencode`, `openclaw`, `zcode`).
 Registry authors can use the canonical [`server.json`](server.json) in the repo root instead of reconstructing the `headroom mcp serve` contract from prose.
diff --git a/docs/content/docs/opencode-deepseek.mdx b/docs/content/docs/opencode-deepseek.mdx
index a9a3594af..6a8c77860 100644
--- a/docs/content/docs/opencode-deepseek.mdx
+++ b/docs/content/docs/opencode-deepseek.mdx
@@ -193,9 +193,52 @@ API key to the proxy, and the proxy forwards it to DeepSeek. Make sure
 
 ### Models appear but requests fail
 
-You ran `headroom wrap opencode`. That command replaces your config with Claude
-and GPT models. **Do not use `headroom wrap`.** Configure OpenCode manually as
-shown above, and launch OpenCode directly with `opencode`.
+You ran `headroom wrap opencode` without telling it about DeepSeek. Wrap
+rewrites the `headroom` provider block in your OpenCode config on every run, so
+the manual `apiKey` / `models` entries from step 4 are replaced. Either launch
+OpenCode directly with `opencode` after configuring it manually as shown above,
+or use wrap with an explicit upstream — see the next section.
+
+### I used `headroom wrap opencode` and get "Incorrect API key provided"
+
+```
+Incorrect API key provided: sk-13005***********************898d.
+You can find your API key at https://platform.openai.com/account/api-keys.
+```
+
+That 401 comes from **OpenAI**, not DeepSeek. `headroom wrap opencode` starts
+the proxy for you, and unless it is told otherwise the proxy forwards
+OpenAI-compatible traffic to its default upstream, `https://api.openai.com/v1`.
+Your DeepSeek key is then presented to OpenAI, which rejects it and points you
+at a dashboard for a key you never had.
+
+Pass the upstream to wrap, exactly like `headroom proxy --openai-api-url`:
+
+```bash
+headroom wrap opencode --openai-api-url https://api.deepseek.com/v1
+```
+
+The equivalent environment variable also works, and is honored by both
+commands:
+
+```bash
+OPENAI_TARGET_API_URL=https://api.deepseek.com/v1 headroom wrap opencode
+```
+
+If a proxy is already running on the port with a different upstream, stop it
+first (`headroom unwrap opencode`) — wrap will not silently re-point a proxy
+that other clients may be sharing.
+
+### When is `headroom wrap opencode` safe?
+
+- **Safe as-is** when your traffic goes to the default upstreams — OpenAI
+  (`api.openai.com`) or Anthropic (`api.anthropic.com`).
+- **Needs `--openai-api-url`** (or `OPENAI_TARGET_API_URL`) for any third-party
+  OpenAI-compatible provider: DeepSeek, Together, OpenRouter, Groq, a
+  self-hosted gateway, and so on.
+- **Use the manual setup in this guide** when you want to pin specific model
+  IDs, context limits, or display names in `opencode.json`, since wrap
+  regenerates the `headroom` provider block each time it runs.
 
 ### "headroom" command not found
 
@@ -223,7 +266,11 @@ shaper is active immediately — the numbers just need calibration.
 ## What's NOT in this guide
 
 - **Claude or GPT models** — this setup uses DeepSeek exclusively
-- **`headroom wrap`** — do not use it; it overrides the config
+- **`headroom wrap` with a custom model list** — wrap regenerates the
+  `headroom` provider block on every run, so the model entries below are lost.
+  If you prefer wrap, run
+  `headroom wrap opencode --openai-api-url https://api.deepseek.com/v1` and skip
+  the manual config
 - **Deprecated model names** — `deepseek-chat` and `deepseek-reasoner` are
   compatibility aliases that will be deprecated on 2026-07-24; use
   `deepseek-v4-pro` and `deepseek-v4-flash` instead
diff --git a/docs/content/docs/opencode.mdx b/docs/content/docs/opencode.mdx
index 6c71d27ff..ca698d377 100644
--- a/docs/content/docs/opencode.mdx
+++ b/docs/content/docs/opencode.mdx
@@ -41,6 +41,7 @@ headroom wrap opencode \
   --no-serena \
   --code-graph \
   --no-proxy \
+  --openai-api-url https://api.deepseek.com/v1 \
   --learn \
   --memory \
   --backend anthropic \
@@ -49,6 +50,14 @@ headroom wrap opencode \
   -- <opencode args>
 ```
 
+Pass `--openai-api-url` when OpenCode should route through a third-party
+OpenAI-compatible provider instead of OpenAI itself — DeepSeek, Together,
+OpenRouter, or a self-hosted gateway. Without it, OpenAI-compatible traffic is
+forwarded to the default upstream (`https://api.openai.com/v1`), so a
+non-OpenAI key is rejected with `401 Incorrect API key provided`. Setting
+`OPENAI_TARGET_API_URL` before wrapping has the same effect. See
+[OpenCode + DeepSeek](/docs/opencode-deepseek) for a full walkthrough.
+
 ## Provider Model Mapping
 
 The generated `headroom` provider exposes these models through the proxy:
@@ -69,6 +78,7 @@ The default model is `headroom/claude-sonnet-4-6`. Change it in `opencode.json`
 |---|---|
 | `OPENCODE_CONFIG_CONTENT` | JSON payload with provider, plugin, and optional local MCP config injected by `wrap` |
 | `HEADROOM_PROXY_URL` | Proxy URL passed to Headroom MCP when a non-default port is used, and to the native plugin when configured |
+| `OPENAI_TARGET_API_URL` | Upstream for OpenAI-compatible traffic when `--openai-api-url` is not passed; defaults to `https://api.openai.com/v1` |
 
 ## Failure Learning
 
diff --git a/headroom/cli/wrap.py b/headroom/cli/wrap.py
index 966d150ac..06a5144ee 100644
--- a/headroom/cli/wrap.py
+++ b/headroom/cli/wrap.py
@@ -7655,6 +7655,16 @@ def openclaw(
     is_flag=True,
     help="Route headroom/* models through the authenticated GitHub Copilot subscription",
 )
+@click.option(
+    "--openai-api-url",
+    default=None,
+    envvar="OPENAI_TARGET_API_URL",
+    help=(
+        "Upstream base URL for OpenAI-compatible traffic, e.g. "
+        "https://api.deepseek.com/v1. Without it the proxy forwards to "
+        "https://api.openai.com/v1 (env: OPENAI_TARGET_API_URL)."
+    ),
+)
 @click.option("--learn", is_flag=True, help="Enable live traffic learning")
 @click.option("--memory", is_flag=True, help="Enable persistent cross-session memory")
 @click.option(
@@ -7672,6 +7682,7 @@ def opencode(
     code_graph: bool,
     no_proxy: bool,
     copilot_subscription: bool,
+    openai_api_url: str | None,
     learn: bool,
     memory: bool,
     backend: str | None,
@@ -7697,9 +7708,25 @@ def opencode(
         headroom wrap opencode --port 9999             # Custom proxy port
         headroom wrap opencode --backend anyllm --anyllm-provider groq
         headroom wrap opencode --copilot-subscription # Use a GitHub Copilot subscription
+        headroom wrap opencode --openai-api-url https://api.deepseek.com/v1
+
+    
+    Without --openai-api-url the proxy forwards OpenAI-compatible traffic to
+    https://api.openai.com/v1, so a third-party key (DeepSeek, Together,
+    OpenRouter, ...) is rejected upstream with OpenAI's 401 "Incorrect API key
+    provided". Point the proxy at the real upstream instead:
+
+    
+        headroom wrap opencode --openai-api-url https://api.deepseek.com/v1
+        OPENAI_TARGET_API_URL=https://api.deepseek.com/v1 headroom wrap opencode
     """
     subscription_resolution = None
     if copilot_subscription:
+        if openai_api_url:
+            raise click.ClickException(
+                "--openai-api-url cannot be combined with --copilot-subscription; "
+                "the subscription resolves its own upstream."
+            )
         effective_backend = backend or os.environ.get("HEADROOM_BACKEND")
         if effective_backend not in (None, "", "anthropic"):
             raise click.ClickException(
@@ -7793,7 +7820,9 @@ def opencode(
         backend=backend,
         anyllm_provider=anyllm_provider,
         region=region,
-        openai_api_url=(subscription_resolution.api_url if subscription_resolution else None),
+        openai_api_url=(
+            subscription_resolution.api_url if subscription_resolution else openai_api_url
+        ),
         copilot_api_token=(subscription_resolution.token if subscription_resolution else None),
         copilot_refresh_oauth_token=(
             subscription_resolution.refresh_oauth_token if subscription_resolution else None
diff --git a/tests/test_cli/test_wrap_opencode.py b/tests/test_cli/test_wrap_opencode.py
index ee0bea009..2bdec77bf 100644
--- a/tests/test_cli/test_wrap_opencode.py
+++ b/tests/test_cli/test_wrap_opencode.py
@@ -1140,3 +1140,116 @@ def test_unwrap_opencode_preserves_utf8_user_content(
     assert "“smart quotes”" in content
     assert "—" in content
     assert wrap_mod._PROVIDER_MARKER_START not in content
+
+
+def _capture_ensure_proxy_kwargs(
+    runner: CliRunner,
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path: Path,
+    argv: list[str],
+) -> dict[str, object]:
+    """Run `wrap opencode` with a stubbed proxy/launch and return _ensure_proxy kwargs."""
+    monkeypatch.chdir(tmp_path)
+    _set_test_home(monkeypatch, tmp_path)
+    captured: dict[str, object] = {}
+
+    def fake_ensure_proxy(port: int, no_proxy: bool, **kwargs):  # noqa: ANN003
+        captured.update(kwargs)
+        return None, port
+
+    with (
+        patch.object(wrap_mod.shutil, "which", return_value="opencode"),
+        patch.object(wrap_mod, "_ensure_proxy", side_effect=fake_ensure_proxy),
+        patch.object(wrap_mod, "_launch_tool"),
+    ):
+        result = runner.invoke(main, argv)
+
+    assert result.exit_code == 0, result.output
+    return captured
+
+
+def test_wrap_opencode_forwards_openai_api_url_to_proxy(
+    runner: CliRunner,
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """--openai-api-url points the proxy at a third-party OpenAI-compatible upstream (#3107)."""
+    monkeypatch.delenv("OPENAI_TARGET_API_URL", raising=False)
+    captured = _capture_ensure_proxy_kwargs(
+        runner,
+        monkeypatch,
+        tmp_path,
+        [
+            "wrap",
+            "opencode",
+            "--port",
+            "9000",
+            "--no-mcp",
+            "--no-serena",
+            "--openai-api-url",
+            "https://api.deepseek.com/v1",
+        ],
+    )
+
+    assert captured["openai_api_url"] == "https://api.deepseek.com/v1"
+
+
+def test_wrap_opencode_honors_openai_target_api_url_env(
+    runner: CliRunner,
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """OPENAI_TARGET_API_URL is honored without the flag, matching `headroom proxy`."""
+    monkeypatch.setenv("OPENAI_TARGET_API_URL", "https://api.deepseek.com/v1")
+    captured = _capture_ensure_proxy_kwargs(
+        runner,
+        monkeypatch,
+        tmp_path,
+        ["wrap", "opencode", "--port", "9000", "--no-mcp", "--no-serena"],
+    )
+
+    assert captured["openai_api_url"] == "https://api.deepseek.com/v1"
+
+
+def test_wrap_opencode_without_openai_api_url_leaves_upstream_unset(
+    runner: CliRunner,
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """No override means the proxy keeps its own default upstream resolution."""
+    monkeypatch.delenv("OPENAI_TARGET_API_URL", raising=False)
+    captured = _capture_ensure_proxy_kwargs(
+        runner,
+        monkeypatch,
+        tmp_path,
+        ["wrap", "opencode", "--port", "9000", "--no-mcp", "--no-serena"],
+    )
+
+    assert captured["openai_api_url"] is None
+
+
+def test_wrap_opencode_rejects_openai_api_url_with_copilot_subscription(
+    runner: CliRunner,
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """The Copilot subscription resolves its own upstream; a manual override would fight it."""
+    monkeypatch.chdir(tmp_path)
+    _set_test_home(monkeypatch, tmp_path)
+    _clear_copilot_route_config(monkeypatch)
+    monkeypatch.delenv("OPENAI_TARGET_API_URL", raising=False)
+
+    with patch.object(wrap_mod, "_ensure_proxy", side_effect=AssertionError("proxy launched")):
+        result = runner.invoke(
+            main,
+            [
+                "wrap",
+                "opencode",
+                "--copilot-subscription",
+                "--openai-api-url",
+                "https://api.deepseek.com/v1",
+            ],
+        )
+
+    assert result.exit_code != 0
+    assert "cannot be combined with --copilot-subscription" in result.output