# Buy Vs Build Decision

> Use when choosing between built-ins, standard libraries, native platform features, installed packages, open source libraries, commercial products, or in-house implementation for a feature or technical design.

- **Type:** Skill
- **Install:** `agentstack add skill-stdin-buy-vs-build-buy-vs-build-decision`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [stdin](https://agentstack.voostack.com/s/stdin)
- **Installs:** 0
- **Category:** [Developer Tools](https://agentstack.voostack.com/c/developer-tools)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [stdin](https://github.com/stdin)
- **Source:** https://github.com/stdin/buy-vs-build/tree/main/skills/buy-vs-build-decision

## Install

```sh
agentstack add skill-stdin-buy-vs-build-buy-vs-build-decision
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Buy vs Build Decision

Make the smallest useful decision memo. The goal is clarity, not ceremony.

## Workflow

1. State the requirement and constraints.
2. Classify it: core (differentiation) or context, and commodity (stable) or novel. Reuse context and commodity work; reserve in-house for core, novel work.
3. Walk the ladder: do nothing, built-in, native platform, installed dependency, open source, commercial, in-house.
4. When several options fit the rung, pick the one that matches the requirement's real shape (directionality, volume, latency, consistency, failure mode), not the most powerful, popular, or familiar one.
5. Compare fit, total cost of ownership, security, licensing, maintenance, integration, maturity, reversibility, and exit risk.
6. Choose the lowest-ownership option that satisfies the constraints. For hard-to-reverse (one-way-door) choices, demand more scrutiny and an exit plan.
7. Name the trigger that would justify revisiting the decision.

## Output

Use this format:

```text
Decision: use .
Why: .
Rejected:  because .
Revisit if: .
```

If building in-house, name the reuse option that failed and the constraint it failed. If adding a dependency or service, name the built-in or installed option that was insufficient.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [stdin](https://github.com/stdin)
- **Source:** [stdin/buy-vs-build](https://github.com/stdin/buy-vs-build)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-stdin-buy-vs-build-buy-vs-build-decision
- Seller: https://agentstack.voostack.com/s/stdin
- Browse the marketplace: https://agentstack.voostack.com/browse

---
Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.