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A2A / Agent2Agent Protocol vs MCP Registry

An independent, evidence-weighted trust comparison of two protocols & tool integration — ranked on verifiable signals, not popularity.

A2A / Agent2Agent Protocol ranks higher with an HVTrust score of 89.3 vs 65.1/100 (Grade A vs B). HVTrust reflects supply-chain safety, transparency, maintenance, and adoption — weighted by how much verifiable evidence exists.
SignalA2A / Agent2Agent ProtocolMCP Registry
HVTrust score89.365.1
Evidence gradeAB
Registry stateListedListed
Safety / Integrity (25)21.213.2
Identity / Provenance (18)18.010.8
Transparency (17)14.414.1
Maintenance (20)16.617.8
Adoption (20)19.19.2
GitHub stars24.1k6.9k
Weekly downloads2,628,077—
Last push2026-06-042026-06-04
LanguageShellGo
OSSF Scorecard7.06.6
Review flags——
Recent change2026-05-29: HVTrust up 10.2pts (75.2 → 85.4)2026-06-04: Rank dropped 11 spots (#84 → #95)
Full A2A / Agent2Agent Protocol report → Full MCP Registry report → All Protocols & Tool Integration →