| layout | title | nav_order | parent |
|---|---|---|---|
default |
Chapter 5: Function Calling |
5 |
OpenAI Realtime Agents Tutorial |
Welcome to Chapter 5: Function Calling. In this part of OpenAI Realtime Agents Tutorial: Voice-First AI Systems, you will build an intuitive mental model first, then move into concrete implementation details and practical production tradeoffs.
Function calling is where realtime agents move from conversation to action. It must be fast, safe, and auditable.
By the end of this chapter, you should be able to:
- implement a reliable tool-call lifecycle
- enforce schema and authorization checks before execution
- design robust error and timeout handling for realtime UX
- return structured outputs that improve downstream response quality
- model emits tool request with arguments
- gateway validates schema and authorization
- tool executes with timeout and retry policy
- structured result (or structured error) returns to session
- assistant synthesizes user-facing response
| Requirement | Purpose |
|---|---|
| strict argument validation | prevents malformed or unsafe calls |
| auth and policy checks | enforces user/tenant permissions |
| timeout budgeting | protects responsiveness |
| idempotency keys | reduces duplicate side effects on retries |
| structured logging | supports forensic debugging |
- acknowledge long-running tools immediately
- stream progress where possible
- provide deterministic fallback when tool backend is unavailable
- never leave the user without a completion/error state
{
"status": "ok",
"data": {"order_id": "123", "state": "shipped"},
"confidence": 0.98,
"trace_id": "tool-req-abc"
}For errors, keep an explicit shape (status, error_code, message, retryable).
- unrestricted tool access from model-generated arguments
- free-form text outputs instead of typed result envelopes
- silent tool failures without user-visible recovery
- long retries that block turn transitions
You now have a production-safe tool-calling blueprint for realtime agents with clear reliability and security controls.
Next: Chapter 6: Voice Output
This chapter is expanded to v1-style depth for production-grade learning and implementation quality.
- tutorial: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- tutorial slug: openai-realtime-agents-tutorial
- chapter focus: Chapter 5: Function Calling
- system context: Openai Realtime Agents Tutorial
- objective: move from surface-level usage to repeatable engineering operation
- Define the runtime boundary for
Chapter 5: Function Calling. - Separate control-plane decisions from data-plane execution.
- Capture input contracts, transformation points, and output contracts.
- Trace state transitions across request lifecycle stages.
- Identify extension hooks and policy interception points.
- Map ownership boundaries for team and automation workflows.
- Specify rollback and recovery paths for unsafe changes.
- Track observability signals for correctness, latency, and cost.
| Decision Area | Low-Risk Path | High-Control Path | Tradeoff |
|---|---|---|---|
| Runtime mode | managed defaults | explicit policy config | speed vs control |
| State handling | local ephemeral | durable persisted state | simplicity vs auditability |
| Tool integration | direct API use | mediated adapter layer | velocity vs governance |
| Rollout method | manual change | staged + canary rollout | effort vs safety |
| Incident response | best effort logs | runbooks + SLO alerts | cost vs reliability |
| Failure Mode | Early Signal | Root Cause Pattern | Countermeasure |
|---|---|---|---|
| stale context | inconsistent outputs | missing refresh window | enforce context TTL and refresh hooks |
| policy drift | unexpected execution | ad hoc overrides | centralize policy profiles |
| auth mismatch | 401/403 bursts | credential sprawl | rotation schedule + scope minimization |
| schema breakage | parser/validation errors | unmanaged upstream changes | contract tests per release |
| retry storms | queue congestion | no backoff controls | jittered backoff + circuit breakers |
| silent regressions | quality drop without alerts | weak baseline metrics | eval harness with thresholds |
- Establish a reproducible baseline environment.
- Capture chapter-specific success criteria before changes.
- Implement minimal viable path with explicit interfaces.
- Add observability before expanding feature scope.
- Run deterministic tests for happy-path behavior.
- Inject failure scenarios for negative-path validation.
- Compare output quality against baseline snapshots.
- Promote through staged environments with rollback gates.
- Record operational lessons in release notes.
- chapter-level assumptions are explicit and testable
- API/tool boundaries are documented with input/output examples
- failure handling includes retry, timeout, and fallback policy
- security controls include auth scopes and secret rotation plans
- observability includes logs, metrics, traces, and alert thresholds
- deployment guidance includes canary and rollback paths
- docs include links to upstream sources and related tracks
- post-release verification confirms expected behavior under load
- openai/openai-realtime-agents Repository
- OpenAI Realtime API Guide
- OpenAI API Deprecations
- OpenAI Agents JavaScript SDK
- OpenAI Python SDK Tutorial
- OpenAI Whisper Tutorial
- Swarm Tutorial
- Vercel AI Tutorial
- Chapter 1: Getting Started
- Build a minimal end-to-end implementation for
Chapter 5: Function Calling. - Add instrumentation and measure baseline latency and error rate.
- Introduce one controlled failure and confirm graceful recovery.
- Add policy constraints and verify they are enforced consistently.
- Run a staged rollout and document rollback decision criteria.
- Which execution boundary matters most for this chapter and why?
- What signal detects regressions earliest in your environment?
- What tradeoff did you make between delivery speed and governance?
- How would you recover from the highest-impact failure mode?
- What must be automated before scaling to team-wide adoption?
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: incoming request volume spikes after release
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: introduce adaptive concurrency limits and queue bounds
- verification target: latency p95 and p99 stay within defined SLO windows
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: tool dependency latency increases under concurrency
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: enable staged retries with jitter and circuit breaker fallback
- verification target: error budget burn rate remains below escalation threshold
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: schema updates introduce incompatible payloads
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: pin schema versions and add compatibility shims
- verification target: throughput remains stable under target concurrency
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: environment parity drifts between staging and production
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: restore environment parity via immutable config promotion
- verification target: retry volume stays bounded without feedback loops
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: access policy changes reduce successful execution rates
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: re-scope credentials and rotate leaked or stale keys
- verification target: data integrity checks pass across write/read cycles
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: background jobs accumulate and exceed processing windows
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: activate degradation mode to preserve core user paths
- verification target: audit logs capture all control-plane mutations
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: incoming request volume spikes after release
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: introduce adaptive concurrency limits and queue bounds
- verification target: latency p95 and p99 stay within defined SLO windows
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: tool dependency latency increases under concurrency
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: enable staged retries with jitter and circuit breaker fallback
- verification target: error budget burn rate remains below escalation threshold
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: schema updates introduce incompatible payloads
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: pin schema versions and add compatibility shims
- verification target: throughput remains stable under target concurrency
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: environment parity drifts between staging and production
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: restore environment parity via immutable config promotion
- verification target: retry volume stays bounded without feedback loops
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: access policy changes reduce successful execution rates
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: re-scope credentials and rotate leaked or stale keys
- verification target: data integrity checks pass across write/read cycles
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: background jobs accumulate and exceed processing windows
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: activate degradation mode to preserve core user paths
- verification target: audit logs capture all control-plane mutations
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: incoming request volume spikes after release
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: introduce adaptive concurrency limits and queue bounds
- verification target: latency p95 and p99 stay within defined SLO windows
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: tool dependency latency increases under concurrency
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: enable staged retries with jitter and circuit breaker fallback
- verification target: error budget burn rate remains below escalation threshold
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: schema updates introduce incompatible payloads
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: pin schema versions and add compatibility shims
- verification target: throughput remains stable under target concurrency
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: environment parity drifts between staging and production
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: restore environment parity via immutable config promotion
- verification target: retry volume stays bounded without feedback loops
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: access policy changes reduce successful execution rates
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: re-scope credentials and rotate leaked or stale keys
- verification target: data integrity checks pass across write/read cycles
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: background jobs accumulate and exceed processing windows
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: activate degradation mode to preserve core user paths
- verification target: audit logs capture all control-plane mutations
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: incoming request volume spikes after release
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: introduce adaptive concurrency limits and queue bounds
- verification target: latency p95 and p99 stay within defined SLO windows
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: tool dependency latency increases under concurrency
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: enable staged retries with jitter and circuit breaker fallback
- verification target: error budget burn rate remains below escalation threshold
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: schema updates introduce incompatible payloads
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: pin schema versions and add compatibility shims
- verification target: throughput remains stable under target concurrency
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: environment parity drifts between staging and production
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: restore environment parity via immutable config promotion
- verification target: retry volume stays bounded without feedback loops
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: access policy changes reduce successful execution rates
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: re-scope credentials and rotate leaked or stale keys
- verification target: data integrity checks pass across write/read cycles
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: background jobs accumulate and exceed processing windows
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: activate degradation mode to preserve core user paths
- verification target: audit logs capture all control-plane mutations
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: incoming request volume spikes after release
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: introduce adaptive concurrency limits and queue bounds
- verification target: latency p95 and p99 stay within defined SLO windows
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: tool dependency latency increases under concurrency
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: enable staged retries with jitter and circuit breaker fallback
- verification target: error budget burn rate remains below escalation threshold
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: schema updates introduce incompatible payloads
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: pin schema versions and add compatibility shims
- verification target: throughput remains stable under target concurrency
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: environment parity drifts between staging and production
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: restore environment parity via immutable config promotion
- verification target: retry volume stays bounded without feedback loops
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: access policy changes reduce successful execution rates
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: re-scope credentials and rotate leaked or stale keys
- verification target: data integrity checks pass across write/read cycles
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: background jobs accumulate and exceed processing windows
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: activate degradation mode to preserve core user paths
- verification target: audit logs capture all control-plane mutations
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: incoming request volume spikes after release
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: introduce adaptive concurrency limits and queue bounds
- verification target: latency p95 and p99 stay within defined SLO windows
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: tool dependency latency increases under concurrency
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: enable staged retries with jitter and circuit breaker fallback
- verification target: error budget burn rate remains below escalation threshold
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: schema updates introduce incompatible payloads
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: pin schema versions and add compatibility shims
- verification target: throughput remains stable under target concurrency
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
- tutorial context: OpenAI Realtime Agents Tutorial: Voice-First AI Systems
- trigger condition: environment parity drifts between staging and production
- initial hypothesis: identify the smallest reproducible failure boundary
- immediate action: protect user-facing stability before optimization work
- engineering control: restore environment parity via immutable config promotion
- verification target: retry volume stays bounded without feedback loops
- rollback trigger: pre-defined quality gate fails for two consecutive checks
- communication step: publish incident status with owner and ETA
- learning capture: add postmortem and convert findings into automated tests
Most teams struggle here because the hard part is not writing more code, but deciding clear boundaries for status, order_id, state so behavior stays predictable as complexity grows.
In practical terms, this chapter helps you avoid three common failures:
- coupling core logic too tightly to one implementation path
- missing the handoff boundaries between setup, execution, and validation
- shipping changes without clear rollback or observability strategy
After working through this chapter, you should be able to reason about Chapter 5: Function Calling as an operating subsystem inside OpenAI Realtime Agents Tutorial: Voice-First AI Systems, with explicit contracts for inputs, state transitions, and outputs.
Use the implementation notes around shipped, confidence, trace_id as your checklist when adapting these patterns to your own repository.
Under the hood, Chapter 5: Function Calling usually follows a repeatable control path:
- Context bootstrap: initialize runtime config and prerequisites for
status. - Input normalization: shape incoming data so
order_idreceives stable contracts. - Core execution: run the main logic branch and propagate intermediate state through
state. - Policy and safety checks: enforce limits, auth scopes, and failure boundaries.
- Output composition: return canonical result payloads for downstream consumers.
- Operational telemetry: emit logs/metrics needed for debugging and performance tuning.
When debugging, walk this sequence in order and confirm each stage has explicit success/failure conditions.
Use the following upstream sources to verify implementation details while reading this chapter:
- openai/openai-realtime-agents Repository
Why it matters: authoritative reference on
openai/openai-realtime-agents Repository(github.com). - OpenAI Realtime API Guide
Why it matters: authoritative reference on
OpenAI Realtime API Guide(platform.openai.com). - OpenAI API Deprecations
Why it matters: authoritative reference on
OpenAI API Deprecations(platform.openai.com). - OpenAI Agents JavaScript SDK
Why it matters: authoritative reference on
OpenAI Agents JavaScript SDK(github.com).
Suggested trace strategy:
- search upstream code for
statusandorder_idto map concrete implementation paths - compare docs claims against actual runtime/config code before reusing patterns in production