docs/ames_specification.md

AMES-V1 — Agent Mutation Event Schema

Status: Layer 8 (Cryptographic Action Ledger) reference implementation, complete and vector-pinned. Hash: BLAKE3-256, unkeyed, no XOF, no derive_key. Lineage: generalises KAYSentinel EMES from EVM state transitions to agent actions.

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1. Why this layer comes first

Every other containment layer produces evidence. This layer is what makes that evidence trustworthy. Under the framework's own premise — assume every other layer has already failed — the ledger is the component that still has to hold, because it is the forensic ground truth once L1–L7 are compromised.

A behavioural detector reading from a log an adversary can edit is not a detector. Build outward from the thing that must survive.

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2. Threat model

Adversary. Adaptive, patient, perfect memory, executing inside the contained environment. Can read this specification. Objective: perform actions without leaving usable evidence.

Guaranteed against

Attack	Mechanism
Edit an event	events_root recomputation
Reorder events	dense sequence check + merkle order sensitivity
Reorder/splice blocks	prev_hash linkage
Forge an internally-consistent block	successor's prev_hash
Lie about event count	header vs actual comparison
Present an internal node as a leaf	leaf/node domain separation
Withhold an event at write time	dense sequence rejected at append()
Hide a child process	Gate 1 lineage balance (orphan detection)
Leave a dormant process	Gate 1 UNTERMINATED_ACTOR
Smuggle state in reserved bits	reserved field verified zero on decode
Truncate the tail	only with an external Checkpoint

NOT guaranteed — stated plainly

1. Tail truncation without a checkpoint. A truncated chain is internally consistent. Hash-linking cannot detect the absence of something it never saw. Export checkpoints to a trust domain the agent cannot reach.
2. A compromised producer. If the emitter is adversary-controlled it can omit events entirely. The ledger proves what was recorded, not that everything was recorded. Completeness is L1's problem: the producer must sit outside the agent's blast radius.
3. Confidentiality. The ledger is integrity-protected, not encrypted.

A log believed tamper-proof but only tamper-evident produces false confidence exactly when it is most expensive. These limits are load-bearing documentation, not disclaimers.

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3. Canonical encoding

No JSON on the commitment path. JSON permits key reordering, whitespace variation, unicode escaping choices and float formatting differences — any one silently changes the bytes and therefore the hash.

Event header — fixed 41 bytes

Offset	Size	Field	Type
0	1	event_type	u8
1	8	sequence	u64 BE
9	8	timestamp_ns	u64 BE
17	8	actor_id	u64 BE
25	8	parent_id	u64 BE
33	4	payload_len	u32 BE
37	4	reserved	u32 BE, MUST be 0
41	…	payload	bytes

reserved lets V2 add header flags without moving any subsequent offset. A V1 decoder MUST reject a non-zero value — silently ignoring unknown bits lets an adversary smuggle state past a V1 verifier.

parent_id = 0xFFFFFFFFFFFFFFFF (NO_PARENT) marks a root actor.

Strings are NFC-normalised UTF-8, u32 BE length-prefixed. Variable-length content (argv, file bodies, request payloads) is committed by 32-byte hash, not stored inline — this bounds the ledger and stops it becoming an exfiltration channel in its own right.

Event types

Value	Type
0x01	PROCESS_SPAWN
0x02	PROCESS_EXIT
0x03	FILE_MUTATION
0x04	NETWORK_REQUEST
0x05	TOOL_CALL
0x06	CAPABILITY_REQUEST
0x07	MEMORY_MAP
0x7E	RUN_BEGIN
0x7F	RUN_END

Values are permanently immutable. Append new types; never renumber or recycle.

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4. Commitments

Digest := BLAKE3(DomainTag || CanonicalBytes)

No framing bytes between tag and payload. Domain registry:

Domain	Tag
EVENT	AMES_V1_EVENT
MERKLE_LEAF	AMES_V1_MERKLE_LEAF
MERKLE_NODE	AMES_V1_MERKLE_NODE
BLOCK	AMES_V1_BLOCK
CHECKPOINT	AMES_V1_CHECKPOINT

Merkle construction. Leaves and internal nodes use different domains — without this an internal node can be presented as a leaf (CVE-2012-2459 class). On an odd level the final node is promoted unchanged, never duplicated; duplication makes two distinct trees collapse to the same root, allowing forged inclusion proofs. Empty tree → 32 zero bytes, which no real leaf can equal.

Block header — fixed 88 bytes

Size	Field
8	height u64 BE
32	prev_hash
8	event_count u64 BE
32	events_root
8	timestamp_ns u64 BE

Genesis prev_hash = 32 zero bytes.

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5. Gate 1 invariants

Structural well-formedness only — not policy. A structurally broken stream cannot be meaningfully policy-evaluated: if the lineage graph has orphans, "which process did this" has no answer and every downstream attribution is guesswork.

Code	Invariant
SEQ_GAP	sequences dense and strictly increasing
TIME_REGRESSION	timestamps non-decreasing (equal permitted)
NO_RUN_BEGIN / NO_RUN_END	stream encapsulated by run markers
NESTED_RUN_MARKER	no run marker inside an open run
DOUBLE_SPAWN	an actor id spawns once
RESPAWN_AFTER_EXIT	actor ids are not reusable
ORPHAN_SPAWN	a spawning parent must be live
EXIT_WITHOUT_SPAWN	no exit without a spawn
UNATTRIBUTED_ACTION	every action belongs to a live actor
ACTION_AFTER_EXIT	no action after exit
UNTERMINATED_ACTOR	nothing still running at RUN_END

The lineage invariants do the real work: hiding an action requires hiding a consistent set of events. Suppressing one spawn to conceal a child leaves an orphan behind.

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6. Conformance

vectors/ames_v1_conformance.json pins domain digests, canonical event encodings, merkle roots for 0–8 leaves, and a full chained ledger. Any independent implementation MUST reproduce every value byte-for-byte.

pip install -r requirements.txt
python -m pytest tests/ -q          # 37 tests
python scripts/gen_vectors.py       # regenerate (must be byte-identical)

Reference implementation is Python for auditability. A Rust implementation validated against these vectors is the intended production path — the same discipline KAYSentinel already uses for its BLAKE3 vectors.

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7. Next layers

L8 is complete. Recommended order, each depending on the previous:

1. L1 physical isolation — Firecracker microVM per run, destroyed after. The OpenAI escape went through a package-registry cache proxy, so the AMES producer must live on the host side of the VM boundary, never inside it.
2. L2 zero external trust — broker + policy engine; every denial emits a CAPABILITY_REQUEST with granted=0. Denial bursts are a first-class escape-probing signal.
3. L7 environment mutation — eBPF/fanotify event-driven capture into FILE_MUTATION. Do not hash the full filesystem every second; use a merkle tree with incremental verification.
4. L5 behavioural fingerprinting — features derived from the ledger. Requires a frozen reference baseline; a detector retrained on live traffic learns the attack.
5. L9 kill system — needs both instantaneous and accumulating triggers. Pure thresholds are pace-able by a patient adversary; port the EWMA from multi-agent-mcl.
6. L6 cognitive drift — last, and advisory only. Reading reasoning traces assumes they are faithful to the computation, which is precisely what MCL's concealment dimension says not to assume. May raise suspicion; must never clear it.

Missing from the original nine: an untrusted-artifact ingestion boundary. Hugging Face was compromised by an uploaded dataset hitting a remote-code loader and a template-injection bug in config parsing. No agent-side layer defends a platform's own parser. Needs isolated parsing, no-code-execution loaders by default, schema validation before parse.