Quantu agent registry

AgentTrust reads two Quantu programs from 8004-solana:

• agent-registry-8004 — agent identity + the give_feedback instruction TrustGate CPIs into.
• atom-engine — confidence-weighted reputation aggregation. AtomStats PDA carries the tier_immediate byte PolicyVault gates against.

Both pinned to commit bfb09ad.

give_feedback CPI

Discriminator: [145, 136, 123, 3, 215, 165, 98, 41].

pub struct GiveFeedbackArgs {
    pub value: u64,
    pub value_decimals: u8,
    pub score: Option<u8>,                      // 0..=100
    pub feedback_file_hash: Option<[u8; 32]>,   // dispute_reason_hash for disputes
    pub tag1: String,                           // ≤ 32 bytes
    pub tag2: String,                           // ≤ 32 bytes
    pub endpoint: String,                       // ≤ 64 bytes
    pub feedback_uri: String,                   // ≤ 256 bytes
}

remaining_accounts ordering for the CPI:

Indexes 0..=3 are required; 4..=7 come as a group of 4 (all four or none). TrustGate's emit_feedback handler validates this in programs/trustgate/src/instructions/emit_feedback.rs.

The SDK's deriveQuantuFeedbackAccounts returns this account bundle correctly ordered.

AtomStats byte-offset reads

PolicyVault's CounterpartyTier policy reads AtomStats via a manual byte-offset parser pinned to commit bfb09ad. Schema-version canary at byte 560 catches drift.

Account size: 561 bytes. Tier domain: 0..=4 (ATOM_TIER_MAX = 4).

Full table: Reference → Byte offsets.

Mainnet vs devnet program IDs

The SDK's MAINNET_QUANTU_IDS and DEFAULT_DEVNET_QUANTU_IDS carry these. NETWORK env on the MCP server drives the right pair: MCP → Install.

Why byte-offset and not Borsh?

Two reasons:

1. Zero Cargo dep on Quantu's crate. AgentTrust would otherwise pin to Quantu's published Anchor IDL or workspace package. A Quantu version bump that re-orders fields would silently change PolicyVault's reads through Borsh's positional encoding. The byte-offset parser is fragile against layout changes — but fragile-with-canary, not fragile-silent. The schema_version byte at 560 fails loud rather than silently misread.
2. Bounded compute. Borsh deserialization allocates and walks the full struct. The byte-offset parser reads exactly the five bytes PolicyVault gates against — risk_score, tier_immediate, tier_confirmed, confidence, schema_version. Cheaper compute units, smaller stack frame.

Trade-off: the parser must be re-pinned manually if Quantu bumps its layout. The pinned-commit comment in policy-vault/src/ext/atom_engine.rs documents the bump procedure.

TrustGate's CPI wrapper

TrustGate's emit_feedback PDA-signs the CPI:

let signer_seeds: &[&[u8]] = &[
    TrustGateAuthority::SEED_PREFIX,    // b"trustgate_auth"
    facilitator.as_ref(),
    &[bump],
];
invoke_give_feedback(&cpi_accounts, &args, signer_seeds)?;

Quantu's give_feedback instruction expects the caller to be the agent's owner. TrustGate's PDA is registered as the feedback authority via Quantu's identity flow on first use (the set_agent_wallet instruction at identity/instructions.rs:506-541 in Quantu's source). The client account in the CPI is set to authority.to_account_info(), so Quantu sees a PDA-signed call rather than the facilitator's wallet directly.

CPI source: programs/trustgate/src/ext/agent_registry.rs.

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