When an API error carries an httpx.Response whose body was consumed via
iter_bytes() during streaming error handling (e.g. GeminiAPIError from
agent/gemini_native_adapter.py), accessing .text raises
httpx.ResponseNotRead. The secondary exception replaced the real,
already-computed provider error (429 free-tier quota guidance) with the
generic 'Attempted to access streaming response content' message on
every turn.
Guard the .text access so it degrades to an empty snippet and falls
through to the str(error) fallback, which carries the full original
message. Mirrors the existing guards in
agent/error_classifier.py::_extract_error_body() and
agent/gemini_native_adapter.py::gemini_http_error().
Fixes#59769
Salvaged from PR #59868 (guard + regression test); the unrelated
desktop Ctrl-C fix bundled in that PR was intentionally dropped and is
triaged separately.
When an LLM API call returns HTTP 4xx with an empty parsed SDK `body` ({}),
`_summarize_api_error` fell through to a bare `str(error)`, so users saw only
"HTTP 400" with no provider detail (reported on Windows in #36109). The SDK
leaves `body` empty in this case, but the httpx `response` still carries the
payload in `.text`.
- run_agent.py `_summarize_api_error`: when `body` is empty, fall back to
`response.text` — parse a JSON `error.message`/`message` when present, else
surface the raw (truncated) body. Platform-agnostic diagnostics.
- hermes_cli/oneshot.py: `hermes -z` now runs via `run_conversation` and returns
exit code 2 when the run is failed/partial with no usable final response, so
scripts can detect LLM failures (still 0 when a response — incl. an error
summary as output — is produced).
Tests: new tests/run_agent/test_summarize_api_error.py (empty-body JSON + raw
text, RED/GREEN verified) + oneshot exit-code/`run_conversation` wiring tests.
NOTE: #36109's original root cause (Windows "all providers return empty 400")
is not reproducible on current main (heavy provider-transport churn since
v0.15.1). This change does not claim to fix that root cause — it makes any
empty-body API error LEGIBLE so a future occurrence shows the real provider
message instead of a bare HTTP 400. Relates to #36109 (does not close it).
