This study investigates how human founders in AI-first startups utilize autonomous AI agents to inform and execute their international expansion strategies. Established internationalization frameworks such as the Uppsala model and International New Venture (INV) theory predict that foreign market entry requires the slow accumulation of experiential knowledge and relational trust. Yet AI-first startups routinely enter multiple foreign markets simultaneously with micro-teams of four to five people and no prior local presence. Explaining this paradox is the study's central motivation. An abductive, exploratory, multiple-case study design was adopted. Empirical data was gathered across two phases: qualitative document analysis of five AI-native scale-ups as an enterprise baseline, and six semi-structured interviews with founders and senior decision-makers from five early-stage startups and one expert interview with a larger enterprise. Three principal findings emerge. First, AI agents function as a synthetic dynamic capability, enabling resource-constrained startups to compress the informational and institutional phases of market entry without equivalent human expertise or prior market exposure, a mechanism termed Synthetic Experiential Learning. Second, founders govern AI outputs across five distinct postures, ranging from layered institutional verification to speed maximalism, driven by sector risk profiles and deal-level stakes rather than a universal rational model. Third, the liability of outsidership decouples into two components: informational outsidership, which AI resolves effectively, and relational outsidership, which remains irreducibly human. This Pre-Relational / Relational Boundary is sector-modulated, holding most firmly in life sciences and deep-tech. These findings are integrated in the AI-Augmented Internationalization Paradigm, a conceptual framework specifying how AI-first startups navigate foreign market entry through three interacting layers: intelligence, governance, and relational. The study contributes to INV theory and the Uppsala model by identifying a new source of dynamic capability, refining the augmentation imperative as conditional rather than universal, and operationalizing the structural boundary where AI-mediated internationalization gives way to irreplaceable human relational work.