feat: auto-load base URL env vars for OpenAI, Anthropic, and Gemini c… by yauheniya-adesso · Pull Request #155 · alexzhang13/rlm

yauheniya-adesso · 2026-04-30T10:49:00Z

Many organisations route API calls through a custom gateway or proxy
(e.g. using OPENAI_API_BASE). Currently these env vars are silently
ignored unless base_url is passed explicitly in code.

This PR adds automatic fallback support in all three main clients:

OPENAI_API_BASE → OpenAI client
ANTHROPIC_BASE_URL → Anthropic client
GEMINI_API_BASE → Gemini client

Also adds .env.example documenting all supported environment variables
across every backend.

No breaking changes — existing behaviour is preserved when env vars are unset.

…lients - OpenAI: reads OPENAI_API_BASE as fallback base_url - Anthropic: reads ANTHROPIC_BASE_URL as fallback base_url; api_key now optional (auto-loaded from ANTHROPIC_API_KEY) - Gemini: reads GEMINI_API_BASE as fallback base_url - Add .env.example covering all supported backends

Copilot

Pull request overview

Adds automatic environment-variable fallbacks for configuring LLM client base URLs, enabling use behind custom gateways/proxies without requiring base_url to be passed explicitly in code.

Changes:

OpenAI client: fall back to OPENAI_API_BASE when base_url is not provided.
Anthropic client: support ANTHROPIC_API_KEY + ANTHROPIC_BASE_URL fallbacks and make api_key optional.
Gemini client: add base_url param and fall back to GEMINI_API_BASE; document supported env vars via new .env.example.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
rlm/clients/openai.py	Adds env fallback for OpenAI base URL (`OPENAI_API_BASE`).
rlm/clients/anthropic.py	Adds dotenv/env defaults for API key + base URL and updates constructor.
rlm/clients/gemini.py	Adds base URL configuration support via env + constructor argument.
.env.example	Documents environment variables for supported backends.

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+        # Fall back to OPENAI_API_BASE env var if base_url is not explicitly provided.
+        if base_url is None:
+            base_url = DEFAULT_OPENAI_API_BASE


+        if api_key is None:
+            api_key = DEFAULT_ANTHROPIC_API_KEY
+
+        if api_key is None:
+            raise ValueError(
+                "Anthropic API key is required. Set ANTHROPIC_API_KEY env var or pass api_key."
+            )
+
+        # Fall back to ANTHROPIC_BASE_URL env var if base_url is not explicitly provided.
+        if base_url is None:
+            base_url = DEFAULT_ANTHROPIC_BASE_URL
+
+        client_kwargs = {"api_key": api_key, "timeout": self.timeout}
+        if base_url is not None:
+            client_kwargs["base_url"] = base_url


+        # Fall back to GEMINI_API_BASE env var if base_url is not explicitly provided.
+        if base_url is None:
+            base_url = DEFAULT_GEMINI_API_BASE
+
        # Configure HTTP options with timeout
-        http_options = types.HttpOptions(timeout=int(self.timeout * 1000))  # milliseconds
+        http_options = types.HttpOptions(
+            timeout=int(self.timeout * 1000),  # milliseconds
+            **({
+                "base_url": base_url
+            } if base_url is not None else {}),
+        )


Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Adds automatic environment-variable fallbacks for configuring custom/proxy API base URLs across the OpenAI, Anthropic, and Gemini clients, and documents supported env vars in a new .env.example.

Changes:

OpenAI client now falls back to OPENAI_API_BASE when base_url isn’t provided.
Anthropic client now falls back to ANTHROPIC_BASE_URL and allows api_key to be omitted (env fallback).
Gemini client now supports GEMINI_API_BASE and forwards it via http_options when present.
Adds .env.example enumerating supported environment variables.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
`rlm/clients/openai.py`	Reads `OPENAI_API_BASE` from env and uses it as default `base_url`.
`rlm/clients/anthropic.py`	Adds dotenv/env fallbacks for `api_key` and `base_url`, and wires `base_url` into Anthropic SDK constructors.
`rlm/clients/gemini.py`	Reads `GEMINI_API_BASE` from env and conditionally forwards it through `types.HttpOptions`.
`.env.example`	Documents expected env vars for multiple backends (OpenAI/Anthropic/Gemini + others).

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yauheniya-adesso · 2026-05-01T08:56:30Z

+        base_url: str | None = None,
        max_tokens: int = 32768,


Fixed — moved base_url after max_tokens to preserve positional argument order.

yauheniya-adesso · 2026-05-01T08:58:27Z

+        # Fall back to ANTHROPIC_BASE_URL env var if base_url is not explicitly provided.
+        if base_url is None:
+            base_url = DEFAULT_ANTHROPIC_BASE_URL
+
+        client_kwargs = {"api_key": api_key, "timeout": self.timeout}


Unit tests for this exact behavior were added in tests/clients/test_base_url_env_vars.py. Specifically, TestAnthropicClientEnvVars::test_base_url_from_env patches DEFAULT_ANTHROPIC_BASE_URL and asserts the value is forwarded to the anthropic.Anthropic constructor, and test_base_url_not_passed_when_env_not_set covers the case where the env var is unset.

yauheniya-adesso · 2026-05-01T09:00:13Z

+        if base_url is None:
+            base_url = DEFAULT_OPENAI_API_BASE


Addressed — tests/clients/test_base_url_env_vars.py covers this. Specifically, TestOpenAIClientBaseUrl::test_base_url_from_env patches DEFAULT_OPENAI_API_BASE and asserts the value is forwarded to the openai.OpenAI constructor, test_explicit_base_url_overrides_env verifies an explicit argument takes precedence, and test_base_url_is_none_when_env_not_set covers the unset case.

yauheniya-adesso · 2026-05-01T09:00:58Z

+        # Fall back to GEMINI_API_BASE env var if base_url is not explicitly provided.
+        if base_url is None:
+            base_url = DEFAULT_GEMINI_API_BASE
+
        # Configure HTTP options with timeout


Addressed — tests/clients/test_base_url_env_vars.py covers this. Specifically, TestGeminiClientBaseUrl::test_base_url_from_env patches DEFAULT_GEMINI_API_BASE and types.HttpOptions and asserts the expected base_url is passed to HttpOptions, test_explicit_base_url_overrides_env verifies an explicit argument takes precedence over the env var, and test_base_url_absent_when_env_not_set covers the unset case.

…pic, and Gemini clients

…ckward compatibility

Copilot

Pull request overview

Adds automatic environment-variable fallbacks for configuring client base URLs (and for Anthropic, API key), enabling organizations to route OpenAI/Anthropic/Gemini traffic through gateways/proxies without requiring explicit base_url arguments in code.

Changes:

Add OPENAI_API_BASE, ANTHROPIC_BASE_URL, and GEMINI_API_BASE env-var fallbacks in the respective clients.
Add ANTHROPIC_API_KEY env-var fallback and validation in AnthropicClient.
Add a consolidated .env.example plus new unit tests covering the fallback behavior.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
`rlm/clients/openai.py`	Loads `OPENAI_API_BASE` and uses it when `base_url` isn’t provided.
`rlm/clients/anthropic.py`	Loads `ANTHROPIC_API_KEY` / `ANTHROPIC_BASE_URL`, adds fallbacks + error on missing key.
`rlm/clients/gemini.py`	Loads `GEMINI_API_BASE` and passes it into `HttpOptions` when provided.
`tests/clients/test_base_url_env_vars.py`	New unit tests validating env-var fallback and precedence behavior.
`.env.example`	Documents supported environment variables across backends.

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+"""
+
+import os
+from unittest.mock import MagicMock, patch


+            with patch("rlm.clients.openai.DEFAULT_OPENAI_API_BASE", "https://my-org.example.com/v1"):
+                client = OpenAIClient(api_key="test-key")
+


+
+            client = OpenAIClient(api_key="test-key", base_url="https://explicit.example.com/v1")
+


+
+            client = OpenAIClient(api_key="test-key")
+


+            from rlm.clients.anthropic import AnthropicClient
+
+            client = AnthropicClient()
+


+            from rlm.clients.gemini import GeminiClient
+
+            client = GeminiClient(api_key="test-key", base_url="https://explicit.example.com")
+


+        ):
+            from rlm.clients.gemini import GeminiClient
+
+            client = GeminiClient(api_key="test-key")


+            from rlm.clients.anthropic import AnthropicClient
+
+            client = AnthropicClient()
+


+            from rlm.clients.anthropic import AnthropicClient
+
+            client = AnthropicClient()
+


yauheniya-adesso · 2026-05-02T19:29:26Z

+            from rlm.clients.gemini import GeminiClient
+
+            client = GeminiClient(api_key="test-key")
+


Fixed — renamed unused client assignments to _ across all three test classes.

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

rlm/clients/openai.py:47

When OPENAI_API_BASE is set to a custom gateway/proxy URL and api_key is omitted, api_key remains None because the env-key fallback only triggers for the default OpenAI base URL (or a few hard-coded provider URLs). This undermines the intended “API key env var fallback” behavior and can lead to an unauthenticated client (depending on SDK behavior). Consider defaulting to DEFAULT_OPENAI_API_KEY for any unrecognized base_url (only overriding it for known providers like OpenRouter/Vercel/Prime), and add a unit test covering OPENAI_API_BASE + omitted api_key to ensure the OpenAI key is still forwarded.

        # Fall back to OPENAI_API_BASE env var if base_url is not explicitly provided.
        if base_url is None:
            base_url = DEFAULT_OPENAI_API_BASE

        if api_key is None:
            if base_url == "https://api.openai.com/v1" or base_url is None:
                api_key = DEFAULT_OPENAI_API_KEY
            elif base_url == "https://openrouter.ai/api/v1":

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yauheniya-adesso · 2026-05-03T20:03:23Z

Addressed the suppressed concern from the "Pull request overview" regarding OPENAI_API_BASE + omitted api_key. Added an else branch in OpenAIClient.init that falls back to DEFAULT_OPENAI_API_KEY for any unrecognized base URL, ensuring custom gateways set via OPENAI_API_BASE are not left unauthenticated. Covered by the new test_openai_api_key_used_for_custom_base_url test.

Copilot AI review requested due to automatic review settings April 30, 2026 10:49

Copilot started reviewing on behalf of yauheniya-adesso April 30, 2026 10:49 View session

Copilot AI reviewed Apr 30, 2026

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docs: clarify .env.example section header for other backends

499df0e

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings April 30, 2026 15:24

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yauheniya-adesso added 2 commits April 30, 2026 17:31

test: add unit tests for base URL env var fallbacks in OpenAI, Anthro…

f96350c

…pic, and Gemini clients

fix: move base_url after max_tokens in AnthropicClient to preserve ba…

15ec3ce

…ckward compatibility

Copilot AI review requested due to automatic review settings May 1, 2026 08:55

Copilot started reviewing on behalf of yauheniya-adesso May 1, 2026 08:56 View session

Copilot AI reviewed May 1, 2026

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yauheniya-adesso added 2 commits May 2, 2026 21:25

fix: rename unused client vars to _ in tests to satisfy ruff F841

b38364f

fix: remove unused MagicMock import and fix import ordering in tests

31449f1

Copilot AI review requested due to automatic review settings May 2, 2026 19:32

Copilot started reviewing on behalf of yauheniya-adesso May 2, 2026 19:32 View session

Copilot AI reviewed May 2, 2026

View reviewed changes

fix: fall back to OPENAI_API_KEY for custom base URLs in OpenAIClient

8087e53

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feat: auto-load base URL env vars for OpenAI, Anthropic, and Gemini c…#155

feat: auto-load base URL env vars for OpenAI, Anthropic, and Gemini c…#155
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yauheniya-adesso:feat/auto-load-base-url-env-vars

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		with patch("rlm.clients.openai.DEFAULT_OPENAI_API_BASE", "https://my-org.example.com/v1"):
		client = OpenAIClient(api_key="test-key")

		from rlm.clients.anthropic import AnthropicClient

		client = AnthropicClient()

		from rlm.clients.gemini import GeminiClient

		client = GeminiClient(api_key="test-key", base_url="https://explicit.example.com")

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