mycelium-agt

Community plugin for the Agent Governance Toolkit (AGT) EvidenceAnchor SPI, backed by Mycelium Trails on Arbitrum.

Evidence hashes are written as immutable trail records via the public argentum.rgiskard.xyz API. Once anchored, records cannot be modified or deleted.

Install

pip install mycelium-agt

Usage

from mycelium_agt import MyceliumAnchor

anchor = MyceliumAnchor(agent_id="my-agent")

# Anchor an evidence hash
receipt = anchor.anchor(
    evidence_hash="sha256:abc123...",
    metadata={"action_type": "file:write", "scope": "audit"},
)
print(receipt.anchor_id)      # trail_id in Mycelium Trails
print(receipt.anchored_at)    # RFC 3339 UTC timestamp

# Verify later
result = anchor.verify("sha256:abc123...", receipt)
print(result.status)          # AnchorVerifyStatus.VERIFIED
print(result.inclusion_proof.proof_data["tx_hash"])

How it works

MyceliumAnchor implements the AGT EvidenceAnchor abstract class:

• anchor(evidence_hash, metadata) — POSTs a trail record to https://argentum.rgiskard.xyz/trails. Returns an AnchorReceipt with a trail_id and deterministic action_ref (RFC 8785 JCS + SHA-256).

• verify(evidence_hash, receipt) — Confirms the hash via GET /trails/verify?action_ref=... (or falls back to GET /trails/{trail_id}). Returns an AnchorVerifyResult with status VERIFIED | NOT_FOUND | HASH_MISMATCH | BACKEND_UNAVAILABLE and an Arbiscan inclusion proof.

Registration with AGT

from mycelium_agt import MyceliumAnchor

# Register with the AGT evidence registry
agt_registry.register("mycelium", MyceliumAnchor(agent_id="my-agent"))

Metadata keys

All optional:

action_ref

Each anchored record gets a deterministic action_ref:

SHA-256(JCS({"agent_id": ..., "action_type": ..., "scope": ..., "timestamp": ...}))

This allows re-derivation and cross-system verification without trusting the receipt alone.

Failure semantics

anchor() raises RuntimeError on network failure. The AGT runtime applies mode semantics (enforce / queue / best_effort). verify() never raises — it returns BACKEND_UNAVAILABLE on network errors.

License

Apache 2.0