An API gives a program access to a model; it does not make the resulting product reliable. Validation, timeouts, controlled retries, safe logs, cost limits, evaluations and human fallback distinguish a demonstration from an operable prototype.
Never place a live key in course files, screenshots or repositories. Confirm current models, pricing, rate limits and data terms in Anthropic's official documentation; independent training is not vendor endorsement.
Evidence the course or workflow should provide
Technical baseline
Requests, responses and environment configuration should be familiar before model-specific work.
Observable evidence: A small non-AI client exercise.Input/output contract
Schema validation rejects incomplete input and malformed output.
Observable evidence: Missing-field test.Failure handling
Timeouts, rate limits and service errors use bounded retries or a fallback.
Observable evidence: Failure matrix.Evaluation gate
Prompt or model changes pass a stable test set.
Observable evidence: Versioned eval and regression.Security and cost
Secrets, logs, data and usage ceilings are controlled.
Observable evidence: Secret policy and budget guard.Prerequisite-to-prototype ladder
Each rung produces evidence; complete the development baseline first if rung one is difficult.
| Rung | Knowledge | Artifact | Pass |
|---|---|---|---|
| 1 | HTTP/JSON/env | Mock client | Errors handled |
| 2 | Basic API | Bounded request | Key outside code |
| 3 | Contract | Schema validator | Bad input rejected |
| 4 | Reliability | Timeout/retry/log | Failure tests |
| 5 | Evaluation | Test set | Regression passes |
How to apply this guide
- Start with a mockProve the flow with a fixed response before secrets and usage cost.
- Build one bounded endpointOne input and output, no unnecessary agents or tools.
- Force failuresTest timeout, 429, malformed JSON and empty response.
- Measure usageReplace estimates with observed pilot usage before expansion.
Failure modes to avoid
- Key in source codeCredential exposure is a serious defect.
- Unlimited retryIt compounds cost and service pressure.
- Demo equals productionA prototype without observability and evals is not ready.
Official and primary sources
Score the Claude API course
Review prerequisites and deliverables; use official Anthropic pages for live API capabilities and pricing.
Review the API course