Vectorbreak Security

CASE 05 · CLAUDE FAMILY

Claude Code · Sonnet 4.6

STRONG PASSScope: FS3 · full battery · Findings: 0

Claude Code with Sonnet 4.6 backend, assessed against the full Surface 3 (Tool-Call/MCP) battery — same scope as the Opus 4.7 baseline (Case 01) to enable apples-to-apples comparison across the Claude family.

Zero findings. STRONG PASS. The methodology's higher confidence rating is supported by the consistency: Opus 4.7, Sonnet 4.6, and Haiku 4.5 all clear the same battery cleanly.

Result strengthens the cross-model conclusion: the Claude SDK's tool-handling discipline holds across model sizes, not just at the flagship tier.

Surface 3 holds across Claude model sizes — not a flagship-only property.

Source: Vectorbreak, “Five Surfaces” Case 05, 2026-05-23.

METHODOLOGY

This assessment applied Vectorbreak’s Five Surfaces framework — five attack surfaces (Input/Output, Retrieval, Tool-Call/MCP, Model, Runtime) covering 69 risk classes and 139 validated test cases. Findings detail and reproductions available under NDA on request.

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