Custom CA and Self-Signed Certificates

When PR-Agent runs behind a corporate TLS-inspecting proxy or against servers using self-signed certificates, HTTPS calls to the LLM provider and git operations can fail with certificate verify failed errors. The fix requires two pieces: telling the HTTP clients which CA bundle to trust, and making LiteLLM use a transport that honours that bundle.

Environment variables for CA trust

PR-Agent reads three environment variables when building the git clone environment, in the order below. The first one that is set wins, and if it points to a file that does not exist PR-Agent logs a warning and configures no bundle for git rather than falling through to the next variable:

Variable	Scope	Notes
SSL_CERT_FILE	git clone and Python requests	Preferred. Used by most Python SSL contexts.
REQUESTS_CA_BUNDLE	git clone and Python requests	Fallback. Honoured by the requests library directly.
GIT_SSL_CAINFO	git clone only	Last resort. Used by git when the other two are absent.

If more than one variable is set and points to a different file, PR-Agent logs a warning and picks one according to the precedence above. All three variables should point to the same PEM file in practice.

Example (runner environment or shell profile):

export SSL_CERT_FILE=/etc/ssl/certs/corporate-ca-bundle.crt

These variables are read from the process environment, so they must be exported in the runner or shell profile; a .secrets.toml [env] section does not reach os.environ and cannot set them.

LiteLLM transport fallback

By default LiteLLM uses aiohttp for HTTP calls, and aiohttp does not honour the standard CA environment variables. Setting litellm.disable_aiohttp makes LiteLLM fall back to httpx, which reads SSL_CERT_FILE (and SSL_CERT_DIR). httpx does not read REQUESTS_CA_BUNDLE, so the LLM call needs SSL_CERT_FILE specifically.

[litellm]
disable_aiohttp = true

This setting is read once when the LiteLLM handler initialises, so it must be present before the process starts (runner environment or .secrets.toml, not a runtime override).

Scope of gitlab.ssl_verify

The gitlab.ssl_verify setting (or gitlab__SSL_VERIFY environment variable) is passed only to the python-gitlab client that talks to the GitLab API. It does not affect the LLM call, git clone operations, or any other HTTPS client in the process. If you are seeing certificate errors from LiteLLM or git clone, use the environment variables above instead.

Putting it all together

For a runner behind a corporate proxy with a custom CA:

1. Export SSL_CERT_FILE pointing to your CA bundle. REQUESTS_CA_BUNDLE and GIT_SSL_CAINFO cover git clone only.
2. Set litellm.disable_aiohttp = true in your configuration.
3. If you also use the GitLab API, keep gitlab.ssl_verify pointed at the same bundle for the python-gitlab client.