v0.21.0 — 2026 literature gap-fill: SCH, PPT, string-payload, HTML/image patterns (mirror of TS v4.32.0)

What's new

Python mirror of npm v4.32.0. Pattern-only release adding 2026 threat-research coverage to 4 guards. No API changes. Zero new dependencies.

agent_skill_guard.py — 4 Semantic Compliance Hijacking (SCH) patterns

agent_communication_guard.py — 7 string-payload patterns + isinstance branch in _validate_payload()

memory_guard.py — 4 Plant-Persist-Trigger patterns

rag_guard.py — markdown_img_alt_injection + html_event_injection

Metrics

• Adversarial recall: 82.1% (1,182 groups / 5,883 payloads — from npm corpus)
• WildChat FPR gate: 494 / 10,000 = 4.94% (unchanged)
• Suite: 949 / 949 pass
• Parity vectors: 46 (Python-handled guards)

Full results: RESULTS-v0.21.0.md

npm counterpart: llm-trust-guard v4.32.0