Previously, `LLM_SECURITY_TRIFECTA_MODE=block` only exited 2 when the
detected trifecta was MCP-concentrated (all three legs via the same MCP
server) or involved sensitive-path + exfil. Distributed trifectas —
three legs originating from different tools, with a non-sensitive data
path and a non-sensitive exfiltration sink — were detected and warned
but not blocked. This mismatched the documented semantics of block mode
and gave operators a false sense of enforcement.
Change: remove the `(mcpInfo.concentrated || sensitiveExfil)` AND-gate
in the `TRIFECTA_MODE === 'block'` branch so any detected trifecta
blocks in block mode. Audit event `severity` still differentiates
critical (concentrated / sensitive-exfil) from high (distributed); the
blocked stderr message now explicitly names "Distributed trifecta:
three legs from different sources" when the confidence sub-signals
are absent.
Addresses critical review 2026-04-20 §2 B2 (HIGH) and §9 row 1
("enforces the Rule of Two").
Tests: 1 added (distributed trifecta in block mode now exits 2).
All 1495 tests pass.
The previous ENV regex `/[\\/]\.env\.[a-z]+$/` only matched a single
lowercase segment after `.env`. Multi-segment and mixed-case variants
such as `.env.production.local.backup`, `.env.stage-1.local`, and
`.env.CI.secret` slipped past the hook. Replaced with
`/[\\/]\.env(\.[A-Za-z0-9._-]+)*$/` which matches `.env` plus any
number of dot-separated alphanumeric/dot/hyphen/underscore segments.
`.envrc` (direnv config, no dot separator) is still allowed.
Addresses critical review 2026-04-20 §2 B1 (HIGH).
Tests: 7 added (6 new multi-segment BLOCK cases + 1 .envrc ALLOW).
All 1494 tests pass.
