## Summary
Two `generateText` call sites were unbilled — identified during the
2026-04-26 incident audit:
- **Thread title generation**
(`AgentTitleGenerationService.generateThreadTitle`) — fires once per new
chat thread; low-volume but completeness matters.
- **Tool-call repair** (`repairToolCall` util, used inside
`experimental_repairToolCall` callbacks) — can fire `MAX_STEPS` times
per agent turn if a model gets stuck producing malformed tool calls.
## What changed
- `AgentTitleGenerationService` — inject `AiBillingService`, expand
`generateThreadTitle` signature to accept `workspaceId` and
`userWorkspaceId`, bill in a `finally` block with
`UsageOperationType.AI_CHAT_TOKEN`. Restructured so the no-default-model
short-circuit happens before the `try`, avoiding a fake billing call.
- `repair-tool-call.util.ts` — added an optional `billingContext` arg
containing `aiBillingService`, `modelId`, `workspaceId`,
`userWorkspaceId`, `operationType`. Wraps the `generateText` call in
`try/finally`; bills in finally with the operation type provided by the
caller. Optional so existing callers keep compiling.
- `chat-execution.service.ts` — threads `billingContext`
(`AI_CHAT_TOKEN`) into the repair callback.
- `agent-chat.service.ts` — passes `workspaceId` and
`thread.userWorkspaceId` to `generateThreadTitle`.
- `agent-async-executor.service.ts` — TODO comment marking that the
repair callback should thread billing once `executeAgent` accepts
`workspaceId` (depends on the executeAgent-finally PR).
## Follow-up
After the executeAgent-finally PR lands, `workspaceId` is in scope at
the `experimental_repairToolCall` callback in
`agent-async-executor.service.ts:198`. Thread `billingContext` through
to fire repair-call billing for workflow agents too, and remove the
TODO. Tiny follow-up.
## Test plan
- [ ] Create a new chat thread; verify a `usageEvent` row is written for
the title generation call.
- [ ] Send a chat message that triggers tool-call repair (e.g. force a
malformed tool call); verify a `usageEvent` row for the repair sub-call.
## Notes for review
- `billingContext` arg made **optional** to allow incremental rollout —
the executeAgent-finally PR plus a small follow-up will close the
agent-async-executor side.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
