Build a metered AI-answer feature

Why use this

1. An AI-answer endpoint can work in a demo while its usage meter misses retries, streaming failures or requests that never reach billing. If product and payment records disagree, users may be charged incorrectly or the team may misunderstand operating costs.

2. This job could make implementation, metering and observability reviewable together. A clear event model would help engineers distinguish answer delivery, chargeable usage and provider cost before a user-controlled release.

Why an agent / simpler alternative

Useful judgment

Connect API behaviour with usage events and propose tests for retries and partial failures.

Simpler alternative

Use a fixed internal prototype without billing when the team only needs to evaluate answer quality.

Unsuitable when

The feature requires live charges, credential creation or production deployment without explicit authorization.

Proposed inputs

1. Name

   Feature contract

   Owner

   Product owner

   Minimum scope

   Answer behaviour, limits, entitlement rules and user-visible errors

   Quality check

   Define what constitutes a completed and billable request.

2. Name

   Repository and measurement design

   Owner

   Engineering owner

   Minimum scope

   Approved interfaces, test accounts and event schema

   Quality check

   Keep provider cost, customer usage and billing amounts distinct.

Access and setup — proposed or unknown

Proposed minimum

1. Work in an authorized development copy with mocked providers and payment events.

Compatibility unknowns

1. Unknown: API access, framework versions, billing integration and deployment compatibility.

External actions requiring approval

1. Creating credentials, changing billing rules, deploying or sending live payment events.

Expected deliverable and review checks

Proposed artifact

Reviewable implementation proposal with metering model, failure tests and staged observability checks.

Critical checks

1. A retried request cannot create duplicate chargeable usage.

2. Failed or cancelled answers follow the agreed billing rule and remain diagnosable.

Missing output evidence

No new run or output inspection in this editorial layer; see linked source-specific limits.

Failure signals and proposed responses

1. Signal

   A network retry records usage twice.

   Why it matters

   The customer could be overcharged even though only one answer arrived.

   Proposed response

   Use a stable request identity and reconcile duplicate events in the proposed design.

2. Signal

   Provider usage is confused with customer entitlement consumption.

   Why it matters

   Costs and invoices may drift in different directions.

   Proposed response

   Maintain separate ledgers and an explicit reconciliation bridge.

Effort and cost — unknown

Setup work

1. Define event semantics and isolated test fixtures.

Ongoing review

1. Review reconciliation alerts, latency outliers and billing discrepancies after approved release.

Unknowns

1. Unknown: provider pricing, infrastructure charges and operational support effort.

First check — proposed, unexecuted

Status

proposed_unexecuted

Synthetic fixture

Synthetic events include one successful answer, its repeated delivery event and a cancelled stream.

Acceptance checks

1. The success consumes entitlement once.

2. The cancelled stream follows an explicit rule rather than an accidental default.

Stop conditions

1. Live credentials, real charges or production deployment is needed.

Limits

1. A metering design is not verified billing accuracy; release and payment behaviour need separately authorized testing.