One defined capability request
A seeded request asked for a TypeScript service that extracts bank-statement transactions, redacts PII, deploys to AWS Lambda, and permits commercial modification.
Proof library
FunctionFoundry / Capability economics
Build versus buy without hand-waving.
Reproducible fixture record
A seeded agent-capability request became a constraint-aware build-versus-buy record with explicit estimates, rights coverage, and a no-spend decision boundary.
Verified July 27, 202612/12Hard requirements covered
213–426kModeled rebuild tokens
10–28kModeled integration tokens
7/7Targeted checks passed
Observed result
FunctionFoundry found a rights-compatible option, measured it against the complete request, and returned evaluate-further instead of manufacturing a savings claim from overlapping estimates.
The comparison was read-only: it spent no funds, created no purchase, and treated acquisition prices as planning inputs requiring a separate confirmed request.
Evidence chain
From known input to bounded conclusion.
Twelve hard requirements
Runtime, deployment, rights, price, security, and feature requirements were compiled before options were ranked.
Build and integration ranges
The deterministic prototype model compared a 213,000–426,000 token rebuild range with a 10,000–28,000 token integration range and a seeded $799 acquisition input.
Evaluate further
The rights-compatible option covered 12 of 12 hard requirements, but overlapping modeled cost ranges prevented a false-precision buy recommendation.
Reproduce it
The record carries its own verification trail.
Node 25.2.1 · pnpm 10.13.1 · Vitest 3.2.7
Download evidence manifestCommand
pnpm exec vitest run \
apps/web/src/lib/build-vs-buy.test.ts \
apps/web/src/app/api/agent/build-vs-buy/route.test.tsSHA-256 fingerprints
Dependency lock396bafe5a089f4edbe3bfdff4f3fc17537d259b1217e9e3001548957bd092a0c
Comparison engine3cea528710928d8295ff29dd564655e34ab2df04be17ecdd49afdf7f5cdd196b
Decision tests7311768d5ca5d1db7c2474883d2d155127b7df38a9fd748a55f3f5517ab9090a
Interpretation boundary
What this record does not claim.
The token ranges are directional planning estimates, not observed agent usage or provider billing.
The $799 acquisition price and two-hour integration estimate are seeded inputs, not live market quotes.
This record demonstrates deterministic decision behavior on a fixture; it is not a claim of realized client savings.
Apply the method