Empty string — caller sends no Ocp-Apim-Subscription-Key header, which IMF Azure APIM masks as HTTP 404 on /data/... endpoints. The ImfHttpError message disambiguates.
IMF_SDMX_SUBSCRIPTION_KEY_SECONDARY is intentionally not read here. It is the cold rotation key, stored only — see analysis/imf/agentic-integration.md §"Pre-warm gate" → "Key rotation".
Resolve the IMF SDMX subscription key.
Resolution order:
override(constructor / CLI argument)process.env.IMF_SDMX_SUBSCRIPTION_KEY(primary, required)Ocp-Apim-Subscription-Keyheader, which IMF Azure APIM masks as HTTP 404 on/data/...endpoints. The ImfHttpError message disambiguates.IMF_SDMX_SUBSCRIPTION_KEY_SECONDARYis intentionally not read here. It is the cold rotation key, stored only — seeanalysis/imf/agentic-integration.md §"Pre-warm gate" → "Key rotation".