session_cap_exceeded - Five Nine

HTTP 403 · type permission. The max_spend_usd you asked for is above the key’s max_spend_usd_per_session cap. Caps are permissions, not rates — this is a per-key guardrail set in the dashboard (new keys default to $5 per session), and the gateway refuses the reservation before anything runs. Nothing was charged.

The shape

{
  "error": {
    "type": "permission",
    "code": "session_cap_exceeded",
    "message": "This key caps sessions at $5.00; the request asked for $12.00.",
    "doc_url": "https://docs.fiveninelabs.com/errors/session_cap_exceeded",
    "request_id": "req_9ya03k",
    "cap_usd": 5,
    "requested_usd": 12
  }
}

How to fix

Lower max_spend_usd to cap_usd or below. Note the ceiling is per run — a session’s follow-up re-aims and refreshes each get their own reservation under the same cap, so a long investigation doesn’t need one giant budget up front.
Or raise the key’s cap in the dashboard (Keys → the key → per-session cap), if you own that decision.
Check the current caps with GET /v1/me.

Reproduce it

Ask for more than your key’s cap (visible in GET /v1/me; default $5):

curl https://api.fiveninelabs.com/v1/sessions \
  -H "Authorization: Bearer $FIVENINE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"query": "vinyl records under $30", "max_spend_usd": 1000}'

The refusal happens at reservation time, so this curl is safe — it can never spend.