Core Concepts

ECP Record

The fundamental unit of evidence. Each record captures one agent action:

{
  "id": "rec_abc123",
  "ts": 1711180800000,
  "agent": "did:ecp:6cda81f6...",
  "step": {
    "type": "llm_call",
    "in_hash": "sha256:64ec88ca...",
    "out_hash": "sha256:8328c36d...",
    "latency_ms": 1200,
    "model": "gpt-4",
    "flags": []
  },
  "chain": {
    "prev": "sha256:previous_record_hash",
    "hash": "sha256:this_record_hash"
  },
  "sig": "ed25519:signature_hex"
}

Key properties:

• in_hash / out_hash: SHA-256 of input/output content. Content stays local.
• chain.prev: Links to previous record — forms an immutable chain.
• chain.hash: Deterministic hash of the entire record (canonical JSON).
• sig: Ed25519 signature proving the agent created this record.

Evidence Chain

Records are linked via chain.prev, forming a chain like blockchain blocks:

[Record 1] → [Record 2] → [Record 3] → ...
  chain.prev    chain.prev    chain.prev
  = "genesis"   = hash(R1)    = hash(R2)

Modifying any record breaks all subsequent chain hashes — tampering is instantly detectable.

Content Vault

Original input/output content is stored locally in ~/.ecp/vault/:

atlast inspect rec_abc123
# Shows: record + original content + hash verification

Content never leaves your device unless you explicitly share it via Proof Package.

Merkle Batch

Records are batched hourly. A Merkle tree is computed over all record hashes:

        Merkle Root
       /           \
    Hash(A+B)    Hash(C+D)
    /     \      /     \
  Rec A  Rec B  Rec C  Rec D

The Merkle root is:

1. Signed with the agent's Ed25519 key
2. Uploaded to the ATLAST server
3. Anchored on-chain via EAS (Ethereum Attestation Service)

Trust Signals

8 behavioral flags are automatically detected:

Flag	Meaning
retried	Same input was sent multiple times
hedged	Multiple models called for same input
incomplete	Response was cut off or empty
high_latency	Response took >5 seconds
error	An error occurred during execution
human_review	Flagged for human review
a2a_delegated	Delegated to another agent
speed_anomaly	Suspiciously fast response

Agent Identity (DID)

Each agent gets a Decentralized Identifier:

did:ecp:6cda81f65ae50c8b148ab57d3e3743da

Backed by an Ed25519 keypair stored in ~/.ecp/identity/. The DID is deterministic — derived from the public key hash.

Proof Package

A self-contained evidence bundle for sharing with auditors:

atlast proof --include-content --output evidence.tar.gz

Contains: records + content + public key + verification script. Verifiers need zero setup.