Veritas Custos

Guardian of Truth

Multi-agent trust verification for the Casper agent economy.

"Casper wants to be the trust layer for the agent economy. Veritas Custos is the trust layer for the agents on Casper."

What It Does

Veritas Custos answers one question on behalf of any agent, protocol, or system on Casper: can this agent be trusted?

It does this by running an account hash through a four-agent verification pipeline, writing a signed trust verdict to the Casper Testnet, and exposing the result through an x402-gated HTTP server. Any downstream agent can query the on-chain trust record and make access decisions accordingly — which is exactly what the included consuming agent demonstrates.

Architecture

Agent Request
     │
     ▼
┌─────────────────────────────────────────────┐
│  x402 HTTP Server (port 8402)               │
│  /verify · /decisions/<tx> · /health        │
└────────────────┬────────────────────────────┘
                 │
    ┌────────────▼─────────────┐
    │     TrustGate Pipeline   │
    │                          │
    │  1. Identity Checker     │  ← CSPR.cloud API: balance, deploys, account age
    │  2. Reputation Oracle    │  ← On-chain contract: registered tier, job history
    │  3. Decision Agent       │  ← Gemini 2.5 Flash: LLM review, tier override
    │  4. Source Attest        │  ← Casper Testnet write: verdict → smart contract
    └────────────┬─────────────┘
                 │
    ┌────────────▼─────────────┐
    │   Odra Smart Contract    │  ← Casper Testnet, immutable trust registry
    │   contract-6f5ac8ab...   │
    └──────────────────────────┘
                 │
    ┌────────────▼─────────────┐
    │   Consuming Agent        │  ← Reads on-chain tier, makes access decision
    │   trust_gate_client.py   │
    └──────────────────────────┘

The Four Agents

1. Identity Checker

Queries the CSPR.cloud REST API to gather raw on-chain signals for the target account: CSPR balance, total deploy count, and account age in days. Computes a deterministic trust score (0–100) across three weighted dimensions:

Dimension	Max Points
Balance	30
Deploys	35
Account Age	35

Outputs a trust score, deterministic tier (High / Medium / Low / Rejected), and full score breakdown.

2. Reputation Oracle

Queries the deployed Veritas Custos smart contract directly to check whether the agent has been previously registered, what tier was last recorded, and how many on-chain jobs have been completed. This is the memory layer — it gives the Decision Agent a longitudinal view, not just a point-in-time snapshot.

3. Decision Agent

Powered by Gemini 2.5 Flash (gemini-2.5-flash, temperature 0.3, maxOutputTokens 4096). Receives the full identity signals and reputation history, then produces a final verdict with three outputs:

final_tier — the authoritative trust classification
adjusted — whether the LLM overrode the deterministic score
reasoning — a human-readable explanation citing the specific field and value that triggered any override (e.g. "jobs_completed = 0 overrides the deterministic High tier despite balance_points = 30/30")

If Gemini is unavailable (503, quota, timeout), the agent falls back gracefully to the deterministic score with a logged explanation — no pipeline failure.

4. Source Attest

Calls casper-client to invoke either register_agent (first time) or update_reputation (subsequent) on the deployed Odra smart contract. The resulting deploy transaction hash is the on-chain proof of verification — immutable, auditable, permanent. Every verdict is also persisted locally as a JSON file keyed by tx hash under agent_verifier/decisions/.

Smart Contract

Built with the Odra framework and deployed to Casper Testnet. Stores per-agent trust records in a contract-level dictionary keyed by account hash.

Field	Value
Contract Package Hash	`contract-package-219bdf679193ca11da406ffa82774ebf21a7745978d43106e90505ead7f51704`
Active Contract Hash	`contract-6f5ac8ab98f5419ff406cd2494b04dd05d6f50db287ab252df9d6473c9b180a9`
Deploy Transaction	`ff66ea0f801579218fec1806e00556058ebd75d68f4cc0523dffce726fff5a19`
Network	casper-test
RPC Node	`http://65.108.41.125:7777`
Entry Points	`register_agent`, `update_reputation`

x402 Payment Layer

The verification endpoint is gated by the x402 micropayment protocol (x402Version: 2). The server declares a payment requirement in CSPR before serving verification results.

On the current state of x402 on Casper:

The server-side facilitator flow is production-correct. However, the production Casper x402 facilitator (x402-facilitator.cspr.cloud) currently supports CEP-18 token settlement only — native CSPR transfers are not yet supported. Additionally, Casper's browser-wallet EIP-712 signing SDK has not yet shipped, which means client-side payment signing cannot be completed from a web context today.

For the demo, the server runs in DEV_MODE (facilitator URL intentionally unconfigured), which skips real settlement while keeping the full x402 negotiation protocol intact. This is the correct engineering response to a gap in Casper's own tooling — not a limitation of Veritas Custos. The /health endpoint confirms:

{
  "mode": "dev",
  "facilitator": "not_configured",
  "x402Version": 2
}

Payment flow can be completed end-to-end the moment Casper ships CEP-18 support and the browser-wallet signing SDK.

Proven On-Chain Transactions

Three independent transactions confirmed on Casper Testnet, covering both contract entry points and two distinct accounts:

Transaction Hash	Type	Account
`de230d7a1af2dff67ffcc3ab0c3132721caa788464bfa04c37774c279ae799c6`	`update_reputation`	Primary
`a78117b6b391c5d0aa5b61b88ac1c906ef40e3861b8330a6e4a790e67e557fe3`	`update_reputation`	Primary
`dbf4a782f5e050f30eb3927fcb26e54062e25e3331eed5c86dca0a578bbb82aa`	`register_agent`	Independent (`23058a429ae...`)

Verify any transaction at testnet.cspr.live.

Consuming Agent Demo

consuming_agent/trust_gate_client.py demonstrates the full trust-layer value proposition: a separate agent reading Veritas Custos's on-chain verdict and making an autonomous access decision based on it.

python3 trust_gate_client.py 7ca9cd84b0e3a34d328fb2c10611871c56c05abb3fc8a49fbcc76c951d0b766f

═══════════════════════════════════════
VERITAS CUSTOS — TRUST GATE CLIENT
Consuming agent access decision demo
═══════════════════════════════════════
Agent:  account-hash-7ca9cd84b0e3a34d328fb2c10611871c56c05abb3fc8a49fbcc76c951d0b766f
Stored tier (on-chain): High
Decision: ACCESS GRANTED ✓
═══════════════════════════════════════
Reasoning: Agent tier 'High' meets minimum threshold (Medium+)
for full system access.

Access policy:

On-Chain Tier	Decision
High / Medium	ACCESS GRANTED
Low	ACCESS RESTRICTED (read-only)
Rejected / Unrated	ACCESS DENIED

Demo Verification Results

Three distinct agent profiles verified end-to-end, showing the full range of pipeline behavior:

High Trust — Established account (95/100)

Balance: 30/30 · Deploys: 30/35 · Age: 35/35
LLM confirms deterministic tier, no override
10 jobs completed, 1912 days account age

Medium Trust — Active but unproven (85/100, overridden)

Score warrants High deterministically
LLM overrides to Medium: jobs_completed = 0 despite strong balance and deploy signals
Demonstrates AI layer adding judgment beyond raw scoring

Low Trust — New account (30/100)

Balance: 30/30 · Deploys: 0/35 · Age: 0/35
No on-chain history, no account age
LLM confirms: no basis for a higher tier

UI

Cinematic space-console HUD served at http://localhost:8402. Features:

Three.js starfield with cinematic intro sequence
Airlock door animation: pneumatic slide-apart on approve, vacuum ejection on reject
Web Audio API synthesized sounds (no external audio files)
Live agent pipeline status with per-step updates
4-axis radar chart (Balance / Deploys / Age / Jobs)
Algorithmic vs AI verdict comparison with OVERRIDE / CONFIRMED badge
Raw verdict JSON toggle fetching from /decisions/<tx_hash>
Tier history tracking across re-verifications

Running Locally

Prerequisites: Python 3.12+, casper-client, WSL2 (Ubuntu 24.04), valid Casper Testnet keys

# Start the server
cd agent_verifier
python3 -u server.py

# Verify an agent (in a separate terminal)
curl -s "http://localhost:8402/verify?account_hash=<account_hash>" \
  -H "X-PAYMENT: dev_payment" | python3 -m json.tool

# Run the consuming agent
cd consuming_agent
python3 trust_gate_client.py <account_hash>

# Check a saved verdict
curl -s http://localhost:8402/decisions/<tx_hash> | python3 -m json.tool

Zero external Python dependencies — stdlib only (urllib, json, subprocess, http.server).

Why Veritas Custos

Veritas Custos is Latin for Guardian of Truth.

The agent economy on Casper faces a trust bootstrapping problem: how does a protocol, DAO, or smart contract decide which agents to grant access to, delegate work to, or accept signed outputs from? On-chain history is public but uninterpreted. Reputation is implicit and siloed.

Veritas Custos makes trust explicit, on-chain, and queryable. It is not a monitoring tool or an analytics dashboard — it is infrastructure. The consuming agent demo shows the end state: any agent in the Casper ecosystem can call query-contract-key against the Veritas Custos registry and receive a trust verdict that was written by a multi-agent pipeline, reviewed by an LLM, and attested on-chain.

That is the trust layer the agent economy needs.

Project Structure

veritas-custos/
├── keys/                        # Casper secp256k1 keypair
├── veritas_custos_contract/     # Odra smart contract (deployed)
├── identity_checker/            # Standalone identity checker
├── agent_verifier/
│   ├── server.py                # x402 HTTP server (port 8402)
│   ├── ui.html                  # Space console HUD
│   ├── trustgate.py             # Pipeline orchestrator
│   ├── decisions/               # Persisted verdict JSONs
│   └── core/
│       ├── identity_checker.py
│       ├── reputation_oracle.py
│       ├── decision_agent.py    # Gemini 2.5 Flash
│       └── source_attest.py
└── consuming_agent/
    └── trust_gate_client.py     # Downstream agent demo

Built for the Casper Agentic Buildathon — DoraHacks, July 2026.

Name		Name	Last commit message	Last commit date
Latest commit History 3 Commits
_reference/veritas-fides		_reference/veritas-fides
agent_verifier		agent_verifier
consuming_agent		consuming_agent
identity_checker		identity_checker
keys		keys
veritas_custos_contract		veritas_custos_contract
.gitignore		.gitignore
CONTRIBUTING.md		CONTRIBUTING.md
LICENSE		LICENSE
README.md		README.md
veritas_custos_logo.png		veritas_custos_logo.png

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Veritas Custos

Guardian of Truth

What It Does

Architecture

The Four Agents

1. Identity Checker

2. Reputation Oracle

3. Decision Agent

4. Source Attest

Smart Contract

x402 Payment Layer

Proven On-Chain Transactions

Consuming Agent Demo

Demo Verification Results

UI

Running Locally

Why Veritas Custos

Project Structure

About

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Veritas Custos

Guardian of Truth

What It Does

Architecture

The Four Agents

1. Identity Checker

2. Reputation Oracle

3. Decision Agent

4. Source Attest

Smart Contract

x402 Payment Layer

Proven On-Chain Transactions

Consuming Agent Demo

Demo Verification Results

UI

Running Locally

Why Veritas Custos

Project Structure

About

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