The design binary previously called process.env.OPENAI_API_KEY without
checking where the key came from. If a user ran $D inside someone
else's project that had OPENAI_API_KEY in its .env, the resulting
generation billed that project's account. Silent and irreversible.
Fix: resolveApiKeyInfo() returns both the key and its source. When the
env-var path matches an OPENAI_API_KEY entry in the current
directory's .env, .env.<NODE_ENV>, or .env.local file, we set a
warning. requireApiKey() prints "Using OpenAI key from <source>" plus
the warning before the run — never the key itself.
Adds 6 unit tests covering: config-vs-env precedence, env-only (no
match), env+cwd .env match, quoted/exported values, value-mismatch
(no false positive), and the no-leak invariant for requireApiKey
stderr output.
Contributed by @jbetala7 via #1278. Closes#1248.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Garry Tan