-- Who was paid, for what, on which mission.
--
-- usage_events recorded tokens and credits and nothing about the provider or
-- model behind them, so the z.ai weekly plan emptied twice (2026-08-29,
-- 2026-09-09) with no row anywhere saying a judge token had been spent. The
-- first signal each time was every done_when mission failing at once.
--
-- `requests` is the count that matters for a plan limit: a verdict is up to
-- MAX_TOOL_CALLS + 1 model calls and a blocked phase used to retry the whole
-- loop 180 times. A request the provider refused with a 429 still counts —
-- it was made.
--
-- All nullable, so every existing writer (cm-billing, world.rs) is untouched
-- and every existing row stays valid.
ALTER TABLE usage_events
    ADD COLUMN IF NOT EXISTS provider   TEXT,
    ADD COLUMN IF NOT EXISTS model      TEXT,
    ADD COLUMN IF NOT EXISTS mission_id UUID REFERENCES missions (id) ON DELETE SET NULL,
    ADD COLUMN IF NOT EXISTS requests   INTEGER;

CREATE INDEX IF NOT EXISTS usage_events_provider_created_idx
    ON usage_events (provider, created_at)
    WHERE provider IS NOT NULL;

COMMENT ON COLUMN usage_events.provider IS 'Provider family that served this usage (e.g. glm, anthropic); NULL on rows written before it was recorded.';
COMMENT ON COLUMN usage_events.requests IS 'Model requests made, including ones the provider refused.';