## Summary
Enterprise users can have an effective monthly credit limit, but Codex
`/status` currently drops that metadata from the account-usage response.
This change adds the optional `spend_control.individual_limit`
projection to the existing rate-limit snapshot flow. The backend client
reads the monthly limit, app-server exposes it as `individualLimit`, and
the TUI renders a `Monthly credit limit` row through the existing
progress-bar renderer.
When the backend does not return an effective monthly limit, existing
rate-limit behavior is unchanged.
## Existing backend state
The account-usage backend already returns the effective monthly limit
and current usage together:
```json
{
"spend_control": {
"reached": false,
"individual_limit": {
"limit": "25000",
"used": "8000",
"remaining": "17000",
"used_percent": 32,
"remaining_percent": 68,
"reset_after_seconds": 86400,
"reset_at": 1778137680
}
}
}
```
Before this change, Codex projected rolling `primary` and `secondary`
windows plus `credits`. It ignored `spend_control.individual_limit`, so
app-server clients and `/status` could not render the monthly cap.
The updated flow is:
```text
account usage backend
-> backend-client reads spend_control.individual_limit
-> existing rate-limit snapshot carries optional individual_limit
-> app-server exposes optional individualLimit
-> TUI renders Monthly credit limit
```
## App-server contract
`account/rateLimits/read` and sparse `account/rateLimits/updated`
notifications now include an additive nullable
`rateLimits.individualLimit` field:
```json
{
"individualLimit": {
"limit": "25000",
"used": "8000",
"remainingPercent": 68,
"resetsAt": 1778137680
}
}
```
In an `account/rateLimits/read` response, `null` means no monthly limit
is available. `account/rateLimits/updated` remains a sparse rolling
notification: clients merge available values into their most recent
`account/rateLimits/read` snapshot or refetch. Nullable account metadata
in a rolling notification does not clear a previously observed value.
## Design decisions
- Extend the existing rate-limit snapshot instead of introducing a
separate request or wire-level update protocol.
- Keep the Codex projection narrow: `/status` needs the effective limit,
current usage, remaining percentage, and reset timestamp.
- Render the monthly row through the existing progress-bar renderer,
with one optional detail line for `8,000 of 25,000 credits used`.
- Keep the backend response optional so existing accounts and older
usage states preserve their current behavior.
- Preserve cached monthly metadata when sparse rolling notifications
omit it. Live account-usage reads remain authoritative and can clear a
removed limit.
## Visual evidence
```text
Monthly credit limit: [██████████████░░░░░░] 68% left (resets 07:08 on 7 May)
8,000 of 25,000 credits used
```
Snapshot:
`codex-rs/tui/src/status/snapshots/codex_tui__status__tests__status_snapshot_includes_enterprise_monthly_credit_limit.snap`
## Testing
Tests: generated app-server schema verification, protocol tests,
backend-client tests, app-server integration coverage, TUI snapshot
coverage, formatting, and workspace lint cleanup.
## Why
Memory startup runs in the background after an eligible turn, but it can
consume Codex backend quota at exactly the wrong time: when the user is
already near a rate-limit boundary. This PR adds a guard so the memory
pipeline backs off when the Codex rate-limit snapshot says the remaining
budget is too low.
## What Changed
- Added `memories.min_rate_limit_remaining_percent` with a default of
`25`, clamped to `0..=100`, and regenerated `core/config.schema.json`.
- Added `codex-rs/memories/write/src/guard.rs`, which fetches Codex
backend rate limits before memory startup and skips phase 1 / phase 2
when the Codex limit is reached or either tracked window is above the
configured usage ceiling.
- Keeps startup best-effort: non-Codex auth or rate-limit fetch/client
failures preserve the existing memory startup behavior.
- Records a `codex.memory.startup` counter with
`status=skipped_rate_limit` when startup is skipped.
- Added config parsing/clamping coverage and guard unit tests.
## Verification
- Added `codex-rs/memories/write/src/guard_tests.rs` for threshold,
primary/secondary window, and reached-limit behavior.
- Added config tests for TOML parsing and clamping.