Use business-case

Build a business case for a build/buy/defer investment decision

Build a business case for a build/buy/defer investment decision — do-nothing always included as the baseline, benefits quantified as re-runnable calculations with confidence tags, full costs (build + run + opportunity), ranges instead of false precision, and the flip-assumption named.

Reach for it when the user needs to justify an investment, write a business case, compare build vs buy vs defer, or get budget/sponsor approval for an initiative.

Install it

npx skilldrop-cli install business-case                 # Claude Code, your user folder
npx skilldrop-cli install business-case --project       # Claude Code, this repo
npx skilldrop-cli install business-case --ide cursor    # or kiro, codex, antigravity, copilot

It is part of the Product manager pack: --pack product-manager installs it with its neighbours.

Ask for it

Say it the way you would to a colleague. Requests like these route to it:

• "Write the business case for building our own feature-flag service versus buying one"
• "Should we invest two engineer-quarters in rebuilding search? I need something to take to the sponsor"
• "Compare build vs buy vs defer for the new data pipeline, with the cost of doing nothing priced"
• "I need budget approval for an observability overhaul — help me justify the spend"

Requests like these belong to a different skill, so it shouldn't answer them:

• "The investment's approved — now write the PRD for the ML router"
• "Pick between Kafka, Kinesis, and Pub/Sub for the approved event bus"
• "Compress this 12-page business case into a one-page summary for the board"

If another skill answers instead, ask for this one by name: "use business-case".

Check what you get

A good result:

• Option 0 is present and costed. A case that doesn't price the status quo hasn't established there's a problem worth money.
• Every benefit is a re-runnable calculation with sourced inputs and a confidence tag. Reviewers check arithmetic; they can't check adjectives.
• Outputs are ranges; the case says which end is likelier. False precision fails the doc even when the direction is right.
• All three cost layers appear per option — build, run, opportunity — with the displaced work named, not waved at.
• The flip-assumption is identified and, where confidence on it is low, a de-risking step is proposed before full commitment.
• The recommendation is singular and the runner-up's best argument is stated fairly. A case that strawmans the alternative converts no skeptics.
• The ask is the first thing read — option, cost, benefit range, deadline, in under 40 words.

See a worked example

• build vs buy flags

Use something else when

• The investment decision is already made — go to prd-draft
• Choosing between technologies for an approved initiative — the investment is already decided; compare the options directly
• Compressing an existing case for execs — exec-summary
• Trivial cost ("should we buy a $400/yr tool") — the case costs more than the decision; just decide

Next

• SKILL.md, the instructions the agent reads
• Its page on the site
• Related: exec-summary, prd-draft

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