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Production miner scoring for Agent Challenge runs on Phala Cloud CPU Intel TDX confidential VMs. The validator host may have no local TDX. Quotes and measurements are produced in Phala guests and re-verified by the challenge service. Operational CLI steps: Quickstart and self-deploy. Key release detail: Key release. Residual risk: table below and security.

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What is measured

A production app-compose plus OS image yield a canonical measurement record: Product os_image_hash:
rtmr3 is treated as runtime and is excluded from the static allowlist pin used in score binding helpers; event-log replay still recovers compose identity and key_provider from RTMR3 events. Miners can reproduce the six-field record with the self-deploy measurements command (challenge repo). Validators publish dual allowlists (review image vs canonical/eval image). A single-field mismatch is NOT-IN-LIST. An empty allowlist fails closed.

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Separate report_data domains

TDX quotes carry a 64-byte report_data field. Agent Challenge binds a domain-separated canonical JSON preimage so stages cannot authorize each other. Mixing domains is a verification failure. Guest wall clock alone never authorizes review freshness. Unattested DB phase labels (review_allowed) are cache only and never alone admit eval CVM or a production score.

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Review CVM vs eval CVM

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Quote verification (trust-but-audit)

Operators and auditors can re-check quotes with dcap-qvl verify or Phala hosted verify. Challenge acceptance is a conjunction of quote integrity, measurement allowlist, event log, domain binding, nonces, review freshness (bound times ≤24h on re-verify), and (for scores) durable key-grant state. This is cryptographically-anchored trust-but-audit. It is not a claim that TEE hardware is free of class attacks.

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Residual risks

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Operational bounds

  • CPU TDX only (tdx.small / tdx.medium). GPUs refused
  • Hard projected spend cap (default $20 for review+eval lifetime) before create
  • Mandatory teardown: phala cvms list should show total: 0 after cleanup
  • No key-grant means no accepted score (even if a guest claimed a number)