fix(agent): preserve env proxies for custom httpx transports

[oneXixi-666]

What does this PR do?

Fixes OpenAI-compatible requests ignoring HTTPS_PROXY / HTTP_PROXY when Hermes injects a custom httpx.HTTPTransport for TCP keepalive socket options.

httpx normally reads environment proxies, but passing a custom transport bypasses that default behavior. This change preserves the existing keepalive transport while explicitly carrying the configured env proxy for non-local endpoints.

Related Issue

Fixes #

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✅ Tests (adding or improving test coverage)

Changes Made

• Added _resolve_httpx_env_proxy() to preserve HTTPS_PROXY / HTTP_PROXY for non-local endpoints.
• Added _build_keepalive_http_transport() to keep keepalive transport construction encapsulated.
• Updated OpenAI client construction to use the helper.
• Added tests for proxy resolution and local endpoint exclusion.

How to Test

1. Configure HTTPS_PROXY=http://127.0.0.1:7890 or HTTP_PROXY=http://127.0.0.1:7890.
2. Use an OpenAI/Codex provider endpoint that requires the proxy.
3. Run:

pytest tests/run_agent/test_create_openai_client_kwargs_isolation.py tests/run_agent/test_create_openai_client_reuse.py tests/agent/test_proxy_and_url_validation.py

Result locally:

19 passed

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: macOS

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• I've updated tool descriptions/schemas if I changed tool behavior — or N/A

Screenshots / Logs

Local targeted test output:

19 passed, 6 warnings

[alt-glitch]

Related to merged #12657 (same root cause). May already be partially fixed — verify against current main.

[alt-glitch]

May overlap with merged #12657.

[teknium1]

Thanks for digging into this proxy regression and for the clean write-up — this is exactly the right fix direction. Unfortunately it's been superseded by an equivalent patch that was already merged before this PR was opened.

Automated hermes-sweeper review found:

• _get_proxy_from_env() and _get_proxy_for_base_url() are live on main at run_agent.py lines 172–201 — same helpers this PR proposes under slightly different names.
• _build_keepalive_http_client() already passes proxy=_get_proxy_for_base_url(base_url) alongside the custom HTTPTransport, the precise fix in this PR (run_agent.py line ~4833).
• Commit 023208b17 (fix(agent): respect HTTP_PROXY/HTTPS_PROXY when using custom httpx transport) is the upstream implementation, cherry-picked from @heykb's PR fix(agent): respect HTTP_PROXY/HTTPS_PROXY when using custom httpx transport #12540 as part of the fix(agent): respect HTTP_PROXY/HTTPS_PROXY when using custom httpx transport #12657 salvage.
• Regression tests covering HTTPS_PROXY forwarding and NO_PROXY exclusion are in tests/run_agent/test_create_openai_client_proxy_env.py (added in d48d6fadff6a).
• Both shipped in release v2026.4.23 (2026-04-23).

The main-branch implementation also adds NO_PROXY awareness for local/loopback endpoints (via urllib.request.proxy_bypass_environment), which goes slightly beyond what this PR covers. Closing as already implemented.