[NOD-002] Node Core-delegating middleware and fail-closed enforcement

[mrnicholasbcarter-code]

User story

Replace policy-adjacent routing authority with Core envelope consumption.

Problem and target state

The current audit identifies a gap that blocks the policy-first, ecosystem-neutral Verdict control plane. Implement the smallest coherent slice described here; preserve existing behavior outside this boundary.

Scope and likely files

src/index.ts, src/middleware/, src/adapters/

Acceptance criteria

• Middleware calls Core decision API, validates envelope, enforces allowed provider/model/tool behavior, returns 503/degraded when Core unavailable, and never silently routes around denial; Express and SSE integration tests pass.

Dependencies and references

Depends on Core NOD-001 and VER-003; extends verdict-node#8 and #1.

Verification plan

• Add or update fixtures at the contract boundary.
• Test success, denial, degraded, unavailable, timeout, and malformed-input paths where applicable.
• Demonstrate that advisory learning/retrieval/provider data cannot weaken hard policy.

Required implementation evidence

• Targeted unit tests and negative-path tests
• Integration/conformance test at the relevant repository boundary
• Security/privacy review for any boundary, persistence, provider, or execution change
• Documentation and migration notes updated
• git diff --check and repository verification commands pass
• Evidence receipt or reproducible test artifact linked in the implementation PR

Definition of done

• Contract and implementation are versioned and backwards-compatibility impact is documented
• Failure, timeout, stale-provider, unknown, and denial states are explicit
• No learning, retrieval, UI, or external provider can bypass Core eligibility or envelope enforcement
• Reviewers can reproduce the acceptance evidence from a clean checkout

[mrnicholasbcarter-code]

Started implementation in isolated worktree. Core decision enforcement, canonical envelope validation, fail-closed denial/unavailable paths, focused tests.

[mrnicholasbcarter-code]

Implemented in PR #25; merged after all required CI checks passed.

[mrnicholasbcarter-code]

Completed via PR #25 (merge ). Added optional Core decision endpoint, canonical decision validation, configured fail-closed 503 behavior for denial/unavailable/malformed/network failures, plus focused tests. CI: Analyze, clean-install, lint passed; CodeQL neutral/skipped.

[mrnicholasbcarter-code]

Evidence correction: PR #25 merged as 9297271. Added optional Core decision endpoint, canonical decision validation, configured fail-closed 503 behavior for denial/unavailable/malformed/network failures, plus focused tests. CI: Analyze, clean-install, lint passed; CodeQL neutral/skipped.