Private client · current full-time engagementIdentity withheld
Portfolio / private release dossier

Rebuilding a legal answer system without loosening the evidence.

I am replacing a production Python answer service with Rust, preserving behavior while tightening retrieval, citations, failure handling, and release control. The client and live product remain private; the engineering record does not.

Follow the replacementCurrent full-time engagement

Release manifest

Authority
Frozen + compared
Runtime
Rust + Axum
Retrieval
Lexical + vector
Evidence
Verified before use
Delivery
HTTP + SSE

Public engineering facts only. Client identity, live surface, and private operating details stay outside this record.

The migration is the work.

Three ordered stations keep replacement work legible: establish authority, reproduce behavior, then improve what evidence proves can improve.

  1. 01

    Rebaseline

    Capture the production authority exactly before replacing any behavior.

    Authority
    Versioned source and runtime behavior become the comparison oracle.
    Parity
    Routes, errors, retrieval order, citations, and streaming contracts are frozen.
    Boundary
    Historical copies stay evidence, never silent fallbacks.
  2. 02

    Port + parity

    Move the serving path into typed Rust crates without redesigning the product contract.

    Domain
    Validated types separate legal identity, text authority, and application state.
    Adapters
    Postgres, model transport, HTTP, and CLI stay outside the pure rules.
    Differential
    Frozen fixtures and live probes expose behavior drift before promotion.
  3. 03

    Answer quality

    Improve recall and answer usefulness without weakening the citation boundary.

    Retrieval
    Hybrid search, companion relationships, and evidence budgets are measured together.
    Answers
    Priority, controlling qualifications, and concise structure are first-class work.
    Release
    Bounded builders, independent review, exact artifacts, and live checks gate change.

The work is not a rewrite. It is controlled replacement.

Search material can help find the right provision. It cannot become a quotation merely because it ranked well. That separation is enforced in the system, not left to prompt wording.

Authority stays frozen

  • The production Python service remains a frozen comparison oracle, not a runtime fallback.
  • Only verified, active-release served text may cross into quotable evidence.
  • Search projections, metadata, and internal audit records stay outside answer prose.
  • Malformed authority-bearing data fails the whole operation before partial results return.

The serving path changes

  • A single Rust serving path owns orchestration from validated request to complete answer.
  • Lexical and vector retrieval share typed identities rather than loose strings.
  • The answer compiler validates citations against the evidence window before delivery.
  • HTTP and keepalive SSE preserve the established public behavior while the internals change.
The frozen authority and current Rust runtime remain separate, connected by a controlled comparison axis.
Evidence pathSearch can nominate · only evidence can support
  1. 01

    Query

  2. 02

    Route

  3. 03

    Retrieve

  4. 04

    Verify

  5. 05

    Compile

Searchable

Projections, metadata, and relationships may rank or route a candidate. They are useful for finding authority, never a substitute for it.

Quotable

Verified served text from the active release can cross the evidence gate and support a cited answer. Everything else stops before compilation.

What I own now.

This is full-time systems work across the answer path: authority, implementation, retrieval, evidence, output quality, and production release.

Current responsibility

Authority + parity
Maintain the frozen comparison baseline and differential gates so changes are measured rather than guessed.
Rust architecture
Own the domain, database, provider, retrieval, answer, application, API, and operational crate boundaries.
Retrieval quality
Tune hybrid retrieval, relationships, routing, and evidence selection against real failure cases and live behavior.
Citation integrity
Keep quotation and citation delivery fail-closed when evidence is missing, stale, malformed, or outside the active release.
Answer quality
Improve concise priority ordering and controlling qualifications without weakening evidence safeguards.
Release control
Package exact changes through bounded implementation, independent review, live probes, and rollback-preserving promotion.
Public stack record
Language
Rust 2024
API
Axum + Tower
Data
PostgreSQL + pgvector
Queries
SQLx · read-only serving role
Retrieval
Lexical + vector + typed relationships
Delivery
JSON + keepalive SSE
Serving now
The answer runtime is a Rust service; Python remains only as frozen compatibility evidence.
Current focus
Retrieval recall, evidence completion, answer structure, controlling qualifications, and contained failure behavior.
Not claimed
Rust does not make database or model latency disappear. Its value here is stronger boundaries, concurrency, operability, and release clarity.

Privacy boundary: This record intentionally omits the client name, product identity, live link, repository, corpus contents, benchmark scores, provider settings, and infrastructure topology.

Need a knowledge system whose evidence boundary survives production?

I can help rebaseline an existing answer service, design a typed retrieval and citation path, or take a private RAG system from evaluation into controlled operation.

Discuss a private RAG systemSee the service scope