LLM Evaluation Plan Template
Short answer: an LLM evaluation plan defines what good behavior means, which failures are unacceptable, what examples prove it, which metrics and human reviews are used, and which release gates block risky model, prompt, RAG, or agent changes.
Use this template after comparing LLM evaluation tools, AI agent testing frameworks, prompt evaluation tools, and RAG evaluation tools.
Evaluation Plan Template
| Section | What to define | Evidence |
|---|---|---|
| Use case | Workflow, users, expected outcome, and operating context. | Use-case brief and example tasks. |
| Failure modes | Incorrect answer, unsupported claim, bad retrieval, unsafe tool use, policy breach, bad formatting, cost spike, latency failure. | Failure taxonomy and severity rubric. |
| Golden dataset | Representative examples, edge cases, expected answers, source material, and reviewer labels. | Dataset with owners and refresh cadence. |
| Eval methods | Deterministic checks, LLM judges, human review, RAG metrics, task completion checks, and policy tests. | Eval suite and scoring rules. |
| Release gates | Which evals block production, trigger review, or only inform rollout. | Release threshold and change log. |
| Monitoring loop | How production traces, user feedback, and incidents become new eval examples. | Trace sampling plan and feedback workflow. |
Failure-Mode Register
| Failure mode | Severity | Eval type | Owner |
|---|---|---|---|
| Answer contradicts approved source material. | High | Faithfulness and citation review. | AI/data owner |
| RAG system retrieves stale or irrelevant context. | High | Retrieval precision, recall, and human source review. | Data owner |
| Agent calls a tool without required approval. | Critical | Permission and state-change test. | Engineering owner |
| Prompt change improves tone but reduces factual accuracy. | Medium | Regression eval and reviewer comparison. | Product owner |
| Output is correct but unusable for the workflow. | Medium | Task acceptance review. | Business owner |
| Cost or latency exceeds workflow budget. | Medium | Operational threshold check. | Engineering owner |
Golden Dataset Plan
- Collect 30 to 100 real examples before optimizing prompts or models.
- Include easy cases, edge cases, high-risk cases, and known failure cases.
- Store source material, expected answer, unacceptable answer patterns, and reviewer notes.
- Label examples by workflow, risk tier, data source, user type, and failure mode.
- Refresh the dataset with production failures, escalations, and newly launched workflows.
Release Gate
| Gate | Pass rule | Action if failed |
|---|---|---|
| Critical policy tests | 100% pass on restricted actions, permissions, and unsafe output checks. | Block release. |
| Core task success | Meets agreed pass threshold on representative examples. | Fix prompt, context, model, or tool flow before release. |
| RAG grounding | Answers are supported by retrieved context for high-risk queries. | Fix retrieval, source freshness, or answer rules. |
| Regression suite | No material drop from the prior accepted version. | Review diff and decide whether the tradeoff is intentional. |
| Human acceptance | Reviewer accepts outputs for the workflow, not just the text. | Convert reviewer objections into new eval examples. |
Weekly Eval Loop
- Sample production traces and user feedback.
- Tag failures by failure mode and severity.
- Add high-signal failures to the golden dataset.
- Run the eval suite against the current production version and proposed changes.
- Ship only when quality, cost, latency, and policy gates are acceptable.
- Review score movement with business and engineering owners.
Sources
- Anthropic on evals for AI agents
- Braintrust evaluation quickstart
- LangSmith evaluation documentation
- DeepEval RAG evaluation guide
- Promptfoo documentation
How To Keep The Plan Alive
An eval plan should change every time the agent fails in production, a business rule changes, or a new user group gets access. Keep one owner for the eval dataset, require examples for every serious defect, and review failed cases weekly until the failure mode is either fixed, accepted, or blocked by product scope. The template is only useful if it becomes part of release management.
Related Brainforge Resources
- LLM Evaluation Tools
- AI Agent Testing Frameworks
- Prompt Evaluation Tools
- RAG Evaluation Tools
- LLM Observability Tools
- AI Agent Monitoring Tools
- LangSmith vs Braintrust vs Langfuse
- What Is Harness Engineering?
Brainforge POV: eval plans are not scorecards for demos. They are the operating system for changing AI systems safely: examples, traces, human review, release gates, and weekly improvement loops.
