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Fix “candidate set is empty”

Stub

This How-to is a stub. Candidate sets are implemented, but “one canonical debug path” is still being refined as inventory + policy + ranking evolve.

Goal​

You will debug empty CandidateSet results by checking registry inventory, selection constraints, and selection-time policy filtering.

When to use this​

  • Selection returns a candidate set with candidates=[].
  • Composite execution fails because no candidates exist.

Prerequisites​

  • Access to Selection Service logs
  • Ability to list node types from Node Registry
  • PDP logs if selection-time policy filtering is enabled

Steps​

  1. Confirm Node Registry has inventory:
  2. Confirm Selection Service can reach Node Registry (network + URL).
  3. Confirm constraints:
    • max candidates not set to 0,
    • allow/deny lists not filtering everything.
  4. Confirm policy filtering isn’t denying all candidates.

Verify​

  • The same subtask produces a non-empty candidate set after fixing inventory/constraints/policy.

Troubleshooting​

  • Inventory empty → seed registry from node packs and restart.
  • Policy denies everything → switch to a dev profile to isolate policy vs selection ranking.
  • Ranking is too strict → return a small ranked set and let binding decide.

Cleanup / Rollback​

  • None.

Next steps​