The original script hardcoded `MODEL_SLUG="openai/gpt-4o"` (slash) and
claimed "non-hermes runtimes ignore the prefix" — wrong for langgraph,
which delegates model resolution to langchain's `init_chat_model`. That
function requires `<provider>:<model>` (colon) and treats slash-form as
OpenRouter routing, falling through without auth even when
OPENAI_API_KEY is set.
Surfaced 2026-05-03 after the a2a-sdk v1 contract bugs (PR
#2558+#2563+#2567) cleared the masking layers — synth-E2E firing
2026-05-03T12:14 returned a properly-shaped task with state=failed +
"Could not resolve authentication method" inside the agent body.
continuous-synth-e2e.yml defaults E2E_RUNTIME=langgraph for the cron,
so every firing hit this. Hermes still gets the slash-form it
needs; claude-code uses the entry-id pattern.
Adds E2E_MODEL_SLUG override for operator-dispatched runs that want
to pin a specific slug.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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