SYS-ADR-07: Zero AI in Ring 1

SYS-ADR-07 is an architectural decision that prohibits AI inference from Ring 1 boundary-ingest services. It is not a preference or a guideline — it is a hard constraint that all four Ring 1 services implement as code, with no escape hatch. This article explains the constraint, the reasoning behind it, and what "zero AI" means in practice for each service.

1. What Ring 1 Is

Ring 1 is the outer boundary of the data plane. It is the set of services that accept raw input from outside the system and write it to durable, immutable storage. In the current implementation, Ring 1 consists of four services:

These services are the first point of contact for data entering the system. Everything they write to service-fs becomes part of the permanent, auditable record. Anything written to the WORM ledger cannot be deleted or modified.

The consequence is that the correctness standard at Ring 1 differs from the correctness standard elsewhere in the system. Mistakes at Ring 1 are permanent.

2. Why Deterministic-Only

Three reasons drive SYS-ADR-07.

Verifiable audit trail. The service-fs hash chain and Ed25519 checkpoint signature create a verifiable record of everything written to Ring 1. A third party can verify the chain from the origin hash to the current tip without replaying any model state. If Ring 1 operations were AI-derived, this verification would be incomplete: auditors would need access to model weights, sampling configuration, and inference state at the time each record was written to understand what the system decided and why. Deterministic operations have no such dependency — the algorithm is the full specification.

Composability guarantee. Ring 1 outputs are consumed by Ring 2 services (service-extraction, service-content) and Ring 3 intelligence (service-slm). For Ring 2 and Ring 3 to compose Ring 1 data reliably, both must be able to reason about what Ring 1 produced. An AI-derived Ring 1 output carries implicit uncertainty that propagates through every downstream computation. A UUID derived deterministically from a lowercase email address carries no such uncertainty — it is the same value everywhere, always.

Regulatory posture. Immutable audit records in regulated industries (financial services, legal, healthcare) require the ability to explain exactly what was recorded and exactly how it was derived. Deterministic algorithms (SHA-256, UUIDv5, regex, Ed25519 signing) have exact, auditable specifications. AI inference does not.

3. What "Zero AI" Means in Practice

SYS-ADR-07 prohibits the following at Ring 1:

• LLM inference calls (via API or local inference)
• Embedding-based similarity computations
• Model weights in the process image
• Probabilistic classification or entity extraction

What is permitted:

• Regular expressions (deterministic pattern matching)
• SHA-256 and other cryptographic hash functions
• UUIDv5 (deterministic from a fixed namespace and input)
• Ed25519 signing and verification
• JSON/XML/OOXML parsing (structural, not semantic)
• Explicit confidence scores assigned by rule, not by a model

The distinction is: computation whose output is fully determined by its input and a fixed algorithm (permitted) versus computation whose output depends on learned weights or stochastic sampling (prohibited).

4. Implementation Instances

service-fs

All operations in service-fs are pure cryptography and file I/O:

• Append — D4 atomic-write (.tmp → fsync → rename → chmod 0o444); SHA-256 entry hash chained from previous
• Checkpoint — SHA-256 root hash over the chain; Ed25519 signature using operator-supplied key; C2SP signed-note wire format
• Anchor-emitter — ephemeral Ed25519 keypair per run; Sigstore hashedRekordRequestV002 POST; deterministic hash of the checkpoint payload

No model, no inference, no probability. Every operation has a single deterministic output for a given input and key.

service-people

Identity extraction uses a single compiled regular expression:

(?i)[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,}

UUID derivation uses UUIDv5:

target_uuid = UUIDv5(NAMESPACE_DNS, lowercase(email))

Confidence scores are assigned by rule: 1.0 for a regex match. No model produces a score between 0 and 1 based on learned representations.

Conflict detection compares UUIDs by equality. When two ingest operations would bind the same email address to different UUIDs, the system surfaces the conflict to the caller — it does not invoke inference to resolve it.

service-email

service-email reads email from Microsoft Exchange via EWS (Exchange Web Services) SOAP protocol. The operations are:

• XML string parsing of SOAP envelopes (structural, not semantic)
• Base64 decoding of MIME content
• HTTP bearer authentication using a pre-acquired token (AZURE_ACCESS_TOKEN)

No content classification, no entity extraction, no spam scoring. The service reads what Exchange provides and writes it to service-fs. Any intelligence applied to email content happens downstream, in Ring 2 or Ring 3, reading from the WORM ledger — never inline during ingest.

service-input

service-input parses documents into text content:

• PDF — structural parsing via oxidize-pdf; extracts text spans
• Markdown — event-stream parsing via pulldown-cmark; strips HTML tags
• DOCX — ZIP + XML paragraph extraction via docx-rust
• XLSX — all-sheets tab-delimited extraction via calamine

In every case, the parser reads format-defined structure and emits text. No semantic interpretation, no summarisation, no classification. The raw extracted text is what lands in service-fs.

5. The Ring 2 Boundary

Intelligence enters the system at Ring 2. service-extraction reads from Ring 1 via MCP and applies deterministic parser combinators plus, optionally, Ring 3 inference calls. Its outputs are Ring 2 artifacts — they do not write back to Ring 1's WORM ledger entries; they create new entries tagged as Ring 2 provenance.

This boundary is structural, not convention-based. Ring 2 services access Ring 1 via HTTP MCP calls. There is no in-process path from Ring 2 inference back into Ring 1 storage. A Ring 2 service that wants to annotate a Ring 1 record creates a new Ring 2 record referencing the Ring 1 entry — it does not modify the Ring 1 entry.

6. SYS-ADR-10 (F12): Surfacing Ambiguity to the Operator

When deterministic processing encounters a situation that cannot be resolved algorithmically — for example, a conflict in service-people where the same email address would map to two different UUIDs — the system returns an error to the caller. It does not:

• Silently pick one of the conflicting records
• Apply a model to guess which is "more likely"
• Merge the records based on heuristic similarity

The F12 requirement (SYS-ADR-10) mandates that ambiguity surfaces to the operator. Resolving the ambiguity is an explicit operator action, not an automatic system behaviour. This is a composability guarantee: operators can reason about what the system decided, because every non-trivial decision goes through the operator.

7. Ring 3: Compositional AI

Ring 3 (service-slm, the Doorman) is where AI inference is intended to run. Ring 3 is architecturally optional — Rings 1 and 2 function fully without it. The intended design is that Ring 3 queries Ring 2, which reads Ring 1, forming a layered composition.

Ring 3 operating at the session layer is not a Ring 1 exception. A query from Ring 3 to Ring 1 data (via Ring 2) uses the same deterministic MCP interface that any other Ring 2 client uses. Ring 3 cannot bypass Ring 1's write discipline; it reads finished Ring 1 records via the same API as everything else.

The compositional model is: deterministic ingest (Ring 1) → deterministic processing (Ring 2) → optional intelligence at query time (Ring 3). Intelligence is value-add, not load-bearing, and never touches the immutable write path.