PromptKit

Value

Problem. Prompts get pasted across repos as half-broken strings. Versioning, variables, and few-shots become tribal knowledge.

How it helps. Versioned YAML/JSON prompt templates with {{variables}}, few-shot slots, OpenAI message export, CLI render, and a tiny eval stub (string match / optional LLM judge BYOK).

Why buy. A prompt-ops kit you run locally — not a hosted CMS.

• YAML/JSON prompts with id + version
• Strict {{var}} interpolation + {{#fewshot}} expansion
• CLI promptkit render + toOpenAIChatMessages export

How it works

flowchart LR
  File["YAML / JSON"] --> Load["loadPromptFile"]
  Load --> Render["renderPrompt"]
  Render --> OpenAI["toOpenAIChatMessages"]
  Render --> Eval["runEval stub"]
  CLI["promptkit render"] --> Load

Mermaid flowchart (render in GitHub / VS Code / mermaid.live).

Use case

Render support-triage.yaml with a ticket variable and pipe messages into chat/completions.

What you get

• Library + CLI
• examples: support-triage, code-review, fewshot-qa
• Eval stub (string_match / llm_judge)
• 21 Vitest tests
• MIT license

Project structure

promptkit/
  src/
    load.ts, render.ts, types.ts
    cli/  eval/  export/openai.ts
  examples/  tests/

Quick start

npm install && npm test && npm run build
npx tsx src/cli/index.ts render examples/support-triage.yaml -v ticket="Please refund order #42"

Example

From examples/support-triage.yaml

id: support-triage
version: "1.0.0"
messages:
  - role: system
    content: You help users of {{product}}.
  - role: user
    content: "{{ticket}}"

Design decisions

• Strict vars by default (fail on missing); --loose opt-in
• Prompts as files in git for reviewable diffs
• Separate EvalHarness for fuller JSONL suites

Limitations

• Not a hosted prompt CMS or collaboration UI
• Eval stub is minimal — full suites → EvalHarness
• LLM judge needs BYOK and is opt-in
• No automatic prompt deployment pipeline

Who it’s for

AI builders who want versioned prompts in git with a CLI.

Not for: Teams needing a multiplayer prompt CMS with approvals.

What you own

Full MIT-licensed TypeScript source via Gumroad ZIP. Fork it, ship it commercially, keep the license notice. You are responsible for secrets, hardening, and production ops.

Related

EvalHarness · AgentForge · RagPipe · McpForge

Demo