Prompt Engineer Toolkit

Prompt Engineer Toolkit

Overview

Use this skill to move prompts from ad-hoc drafts to production assets with repeatable testing, versioning, and regression safety. It emphasizes measurable quality over intuition. Apply it when launching a new LLM feature that needs reliable outputs, when prompt quality degrades after model or instruction changes, when multiple team members edit prompts and need history/diffs, when you need evidence-based prompt choice for production rollout, or when you want consistent prompt governance across environments.

Core Capabilities

• A/B prompt evaluation against structured test cases
• Quantitative scoring for adherence, relevance, and safety checks
• Prompt version tracking with immutable history and changelog
• Prompt diffs to review behavior-impacting edits
• Reusable prompt templates and selection guidance
• Regression-friendly workflows for model/prompt updates

Key Workflows

1. Run Prompt A/B Test

Prepare JSON test cases and run:

python3 scripts/prompt_tester.py \
  --prompt-a-file prompts/a.txt \
  --prompt-b-file prompts/b.txt \
  --cases-file testcases.json \
  --runner-cmd 'my-llm-cli --prompt {prompt} --input {input}' \
  --format text

Input can also come from stdin/--input JSON payload.

2. Choose Winner With Evidence

The tester scores outputs per case and aggregates:

• expected content coverage
• forbidden content violations
• regex/format compliance
• output length sanity

Use the higher-scoring prompt as candidate baseline, then run regression suite.

3. Version Prompts

# Add version
python3 scripts/prompt_versioner.py add \
  --name support_classifier \
  --prompt-file prompts/support_v3.txt \
  --author alice

# Diff versions
python3 scripts/prompt_versioner.py diff --name support_classifier --from-version 2 --to-version 3

# Changelog
python3 scripts/prompt_versioner.py changelog --name support_classifier

4. Regression Loop

1. Store baseline version.
2. Propose prompt edits.
3. Re-run A/B test.
4. Promote only if score and safety constraints improve.

Script Interfaces

• python3 scripts/prompt_tester.py --help
  • Reads prompts/cases from stdin or --input
  • Optional external runner command
  • Emits text or JSON metrics
• python3 scripts/prompt_versioner.py --help
  • Manages prompt history (add, list, diff, changelog)
  • Stores metadata and content snapshots locally

Pitfalls, Best Practices & Review Checklist

Avoid these mistakes:

1. Picking prompts from single-case outputs — use a realistic, edge-case-rich test suite.
2. Changing prompt and model simultaneously — always isolate variables.
3. Missing must_not_contain (forbidden-content) checks in evaluation criteria.
4. Editing prompts without version metadata, author, or change rationale.
5. Skipping semantic diffs before deploying a new prompt version.
6. Optimizing one benchmark while harming edge cases — track the full suite.
7. Model swap without rerunning the baseline A/B suite.

Before promoting any prompt, confirm:

• Task intent is explicit and unambiguous.
• Output schema/format is explicit.
• Safety and exclusion constraints are explicit.
• No contradictory instructions.
• No unnecessary verbosity tokens.
• A/B score improves and violation count stays at zero.

References

• references/prompt-templates.md
• references/technique-guide.md
• references/evaluation-rubric.md
• README.md

Evaluation Design

Each test case should define:

• input: realistic production-like input
• expected_contains: required markers/content
• forbidden_contains: disallowed phrases or unsafe content
• expected_regex: required structural patterns

This enables deterministic grading across prompt variants.

Versioning Policy

• Use semantic prompt identifiers per feature (support_classifier, ad_copy_shortform).
• Record author + change note for every revision.
• Never overwrite historical versions.
• Diff before promoting a new prompt to production.

Rollout Strategy

1. Create baseline prompt version.
2. Propose candidate prompt.
3. Run A/B suite against same cases.
4. Promote only if winner improves average and keeps violation count at zero.
5. Track post-release feedback and feed new failure cases back into test suite.

When to Use

Analyzes and rewrites prompts for better AI output, creates reusable prompt templates for marketing use cases (ad copy, email campaigns, social media), and structures end-to-end AI content workflows.

Covers: Core Capabilities, Key Workflows, Choose Winner With Evidence, Version Prompts, Add version.