Verify every non-trivial framework/library/tool decision against official documentation BEFORE implementing. Cite sources inline. Flag what's unverified. Reject hallucinated API surfaces. Pairs with `engineering-standards` (this skill is the active discipline; engineering-standards is the broad reference). The agent's natural failure mode is plausible-sounding API code that doesn't exist; this skill is the counter. Use when implementing against any external library/framework/tool, when answering "does X support Y?", when writing example code for unfamiliar APIs, or when adopting a new dependency.
