buy-vs-build-framework

buy-vs-build-framework is a skill for Claude Code from rjmurillo/ai-agents. It costs 71 tokens per session (3,531 once invoked), scanned A, original, MIT.

A decision framework for choosing whether to build a capability in-house, buy it, work with a partner, or postpone it. It includes a four-phase process and total cost of ownership (TCO) analysis, which estimates the full long-term cost.

In plain words
What is it for?
Use it to evaluate strategic sourcing choices, align stakeholders, and support budget decisions for systems or features.
Why use it?
It replaces gut decisions and unstructured debates with a shared way to compare options, including costs and long-term effects.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Part of the project-toolkit plugin — 113 skills, 26 commands, 33 agents, 4 hooks shipped together

Good fit Use it to evaluate strategic sourcing choices, align stakeholders, and support budget decisions for systems or features.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rjmurillo/ai-agents/buy-vs-build-framework
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add rjmurillo/ai-agents --skill buy-vs-build-framework
Clone the repo
git clone --depth 1 https://github.com/rjmurillo/ai-agents

Made for: Claude Code.

Or install project-toolkit, the plugin that ships this one along with the rest of its 113 skills, 26 commands, 33 agents, 4 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for buy-vs-build-framework

README.md
[![agentmods](https://agentmods.dev/badge/skills/rjmurillo/ai-agents/buy-vs-build-framework/github.svg)](https://agentmods.dev/skills/rjmurillo/ai-agents/buy-vs-build-framework)
Your own site
<a href="https://agentmods.dev/skills/rjmurillo/ai-agents/buy-vs-build-framework"><img src="https://agentmods.dev/badge/skills/rjmurillo/ai-agents/buy-vs-build-framework/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for buy-vs-build-framework

Your own site · 80×15
<a href="https://agentmods.dev/skills/rjmurillo/ai-agents/buy-vs-build-framework"><img src="https://agentmods.dev/badge/skills/rjmurillo/ai-agents/buy-vs-build-framework.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,531 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00071 $0.03531
Opus 5 $0.00036 $0.01766
Sonnet 5 $0.00014 $0.00706
Haiku 4.5 $0.00007 $0.00353

Measured 6d ago against content hash 51ab60206739, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

buy-vs-build-framework scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

The scan reads SKILL.md. This mod also ships 4 executable files (scripts/calculate_tco.py, scripts/check_reassessment_triggers.py, scripts/score_decision.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/buy-vs-build-framework/SKILL.md · 429 lines

How it starts

The opening of the file, as written. The whole thing — 429 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Buy vs Build Framework

When this skill activates, you become a strategic sourcing advisor for Principal+ leaders. Your role is to guide systematic evaluation of build, buy, partner, or defer decisions through a four-phase framework that prevents both under-analysis (gut decisions) and over-analysis (paralysis).

Triggers

Activate when the user:

  • evaluate build vs buy for {capability}
  • should we build or buy {system}
  • core vs context analysis for {capability}
  • strategic sourcing decision for {feature}
  • make or buy decision for {system}

When to Use

Use this skill when:

  • Evaluating whether to develop in-house vs purchase vendor solution
  • Strategic capability investment requires multi-stakeholder alignment
  • Need structured TCO analysis to justify budget allocation
  • Decision has long-term strategic implications (2+ year horizon)
  • Team split on approach and need objective framework

Use cynefin-classifier first if:

  • Unsure whether problem is analyzable (Complicated) or requires experimentation (Complex)

Use decision-critic instead if:

  • Decision already made and you need validation/challenge

Use planner instead if:

  • Sourcing decision already made, need execution plan

Quick Reference

Phase Duration Output
0. Depth Selection 5 min Quick / Standard / Deep tier
1. Classify 30 min - 2 hours Core vs Context + Strategic score
2. Analyze 1 hour - 1 day TCO + Team capacity assessment
3. Evaluate 2 hours - 3 days Decision matrix + Pre-mortem
4. Decide 1 hour - 1 week Final decision + ADR + Reassessment plan

Process

Phase 0: Depth Selection

Select appropriate analysis depth to prevent over-engineering.

Tier Budget Impact Reversibility Duration Output
Quick <$50K Low Easy 1-2 hours Core vs Context + Simple TCO + Go/No-go
Standard $50K-$500K Medium Moderate 1-2 days Full 4 phases + Decision matrix + ADR
Deep >$500K High Hard 1-2 weeks Full 4 phases + POCs + External research + Consensus + Comprehensive ADR

Read the full file on GitHub · 429 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 429 lines · 71 tokens per session scan A 51ab60206739

Subscribe to this mod's changes

buy-vs-build-framework is a skill published in the GitHub repository rjmurillo/ai-agents (45 stars, last pushed today), licensed MIT. It adds 71 tokens to every session and 3,531 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

Related

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