Skip to main content

Downscope tokens per NodeRun for least privilege

Stub

This How-to is a stub. JARVIS uses token exchange, but full per-node-run downscoping semantics are planned and not yet enforced end-to-end.

Goal​

You will enforce least-privilege delegation by minting downscoped tokens for each NodeRun.

When to use this​

  • You want write/irreversible nodes to carry tighter permissions.
  • You want robust blast-radius limits for prompt injection failures.

Prerequisites​

  • An STS that can issue scoped tokens (audience + optional scopes/claims)
  • A policy model that maps node metadata to permissions
  • A place to store downscoping evidence (token claims, decision records)

Steps​

  1. Define a mapping from NodeType metadata → required permissions.
  2. Before executing a NodeRun, exchange/mint a token with:
    • the callee’s aud,
    • the minimal permission claims for that node.
  3. Validate the token on the callee side and enforce claims in policy.

Verify​

  • Tokens differ per node run (scoped claims are visible).
  • A token minted for one node cannot be used to execute a more privileged node.

Troubleshooting​

  • Too hard to map permissions → start with coarse “read/write/irreversible” tiers.
  • Claims not enforced → ensure PDP uses claims in its principal context.
  • Token bloat → keep claims minimal and move details to policy metadata.

Cleanup / Rollback​

  • Rotate client secrets and revoke issued tokens if compromised.

Next steps​