Sentinel Payment Preflights v0.3.0

Sentinel v0.3.0 adds a second deterministic, read-only MCP tool: preflight_x402_v2_payment_required.

The new tool inspects exactly one decoded inline x402 v2 PaymentRequired JSON document under a pinned, closed-world Sentinel safety profile limited to exact, canonical eip155:<chain-id>, and EIP-3009 transfer metadata. It applies nine bounded checks, rejects duplicate JSON keys, evaluates every advertised payment alternative, and never copies supplied payment values into model-visible findings.

This is structural preflight only. It does not decode HTTP headers, fetch requester URLs, evaluate payer policy, request or verify signatures, connect a wallet, submit a payment, settle funds, verify receipts, verify chain or token behavior, prove address ownership, or implement a general x402 client/server. A clear result authorizes no payment.

The existing preflight_agent_payment_boundary tool and two read-only Sentinel service resources remain available.

Artifact verification:

• MCPB SHA-256: dd3582fbc24d43569ada443df8d2c069ba4be157146d7e17921b558ec07d9757
• clean-room MCP tests: 45/45
• source-site tests: 27/27
• packaged server smoke-tested over stdio with both tools listed
• npm audit: 0 vulnerabilities

Sentinel Agent Payment Boundary Preflight v0.2.0

A read-only deterministic preflight for public agent and payment metadata. The bundle includes its Node dependencies and requires no API key or wallet access. It submits no quote request, authorizes no payment, and moves no funds. Optional paid review remains a separate quote-first service: https://terminallylazy.github.io/sentinel-recovery-support/#services.