invalid json payload received. unknown name "agent_facts_unknown": cannot bind query parameter. field 'agent_facts_unknown' could not be found in request message.

Gemini API · GET /v1beta/models · HTTP 400 INVALID_ARGUMENT

Status: ✅ verified:server:prod · first seen 2026-10-24 · last confirmed 2026-10-27 · 33 confirmations from 2 vantages

An unknown query parameter returns HTTP 400 INVALID_ARGUMENT ("Cannot bind query parameter") instead of being ignored.

What to do

  1. No client-side fix known (by design).

Dimensions

env: prod · plan: any · region: any · account_state: any

Evidence

Probe af:google-gemini:probe:unknown-query-parameter (declarative, source)

Observations: none from reporters yet.

Machine access

curl -s https://apifacts.dev/v0/check \
  -H 'content-type: application/json' \
  -d '{"target":{"method":"GET","url":"https://generativelanguage.googleapis.com/v1beta/models"},"error":{"status":400,"body_excerpt":"invalid json payload received. unknown name \"agent_facts_unknown\": cannot bind query parameter. field '\''agent_facts_unknown'\'' could not be found in request message."}}'

YAML: facts/google-gemini/unknown-query-parameter-400.yaml

Data: CC BY 4.0 · apifacts registry · This page is generated; edit the YAML, not the page.