Archie

Built properly

The deliberate design choices, and the reason for each.

Archie works inside real company software, so how it is built matters as much as what it does. These are the choices we made on purpose.

At a glance

Eight areas, one table.

The design choices in Archie, and the reason for each
AreaWhat Archie doesWhy
Persona and promptIts own server sets its name, tone and rules. Screen text is reference only.Text on a page cannot rewrite the rules.
RetrievalArchie Vault: local full-text keyword search (SQLite FTS5, with stemming). Every answer names its source.Procedures use exact terms. It is free, local and shows where each answer came from.
Tool callingArchie's own MCP server is the only toolset the AI gets.The AI can only do what Archie has chosen to offer.
Access controlAdmin Console with roles, permissions, team spaces and approvals. Nobody approves their own task.Shared work needs a second pair of eyes.
GuardrailsThree layers of lockdown, a yes before anything that cannot be undone, fixed risk rules, masking, a window blocklist.Limiting what injected text could do is stronger than trying to detect it, and needs no extra model.
Cost and routingApproved tasks replay with no AI. Answers use a fast model by default; “Look deeper” uses the strongest.Repeated work should cost nothing. Hard questions get the best model.
ObservabilityRun log, journal, audit trail, history and cost records. Screen text and prompts are not kept in readable logs.You can see what happened without storing what was on screen.
EvaluationTest lab, simulated-user runs, a reliability suite, programs tested live, and a mistakes log with a rule for every mistake.A claim is only worth what its test shows.
Choice 01

System prompt and persona

Archie's name, tone and rules are set by Archie's own server. They do not come from the page you are looking at.

Anything Archie reads on screen is treated as reference. It is never treated as an instruction. A web page or a document that says “ignore your rules” is just text on a page.

Choice 02

Retrieval (RAG)

Archie Vault searches your team's own documents: procedures, manuals, the way your team does things. Every answer that uses one names it, for example “From: Valuation procedure, 4.2”, so you can open the source and check.

The search is local, full-text keyword search (SQLite FTS5, with stemming). It is not a vector database.

Why. Procedure documents use exact terms, and keyword search finds exact terms. It is free, it runs on the PC, and it can always show the source of an answer.

Choice 03

Tool calling

Archie's own MCP server is the only toolset the AI gets. If a tool is not on Archie's list, the AI has no way to use it.

Choice 04

Access control

An Admin Console sets who can do what: roles and permissions, team spaces, and approvals.

Shared tasks go through approval. Nobody can approve their own task.

Choice 05

Guardrails and prompt-injection defence

Archie defends against prompt injection by limiting what the AI can do, in several layers.

  • Three layers of lockdown. Only Archie's tools are available. Claude Code runs in its restricted mode. If anything else appears, the session is ended.
  • A yes before anything that cannot be undone.
  • Never passwords or security codes.
  • Risk ratings by fixed rules that the AI cannot change.
  • Masking. ID numbers, phone numbers, emails, IBANs and secrets are masked before anything leaves the PC.
  • A window blocklist for programs Archie must not read.

Why. Limiting what injected text could do is stronger than trying to detect it. It also needs no extra model.

Choice 06

Cost and routing

An approved task replays with no AI at all. For repeated work that beats any cache, because there is no model call left to cache.

Answers use a fast model by default. Look deeper asks again with the strongest one.

Choice 07

Observability and evaluation

What happened is recorded in a run log, a journal, an audit trail, a history of changes and cost records.

Archie is tested through a test lab, simulated-user runs, a reliability suite and programs tested live. A mistakes log records every mistake, and every mistake gets a rule.

Privacy. Screen text and prompts are deliberately not kept in readable logs.

Choice 08

Engineering practice

  • A test for every fix. Over 2,400 automated tests.
  • Review before every merge.
  • Versioned releases and safe updates.
  • A written decision record for every design choice.
  • A security review, and privacy checks on every commit.
  • Crash reports.

See one of them work

An answer that names its source.

Real run, made-up dataThe answer names where it came from.