fde — a framework for Forward Deployed Engineers

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fde is an open-source framework for Forward Deployed Engineers: it takes a client engagement from a problem statement to a runnable, deployable AI project — with every decision traced to a fact, and every fact traced to a source.

Not an agent framework — the thing that decides whether you need one, picks it as a stack when you do, and grades what it builds.

Forward deployed engineers arrive with incomplete information, a client who may not know what they need, and a deadline. This is the tooling for that: structured discovery and requirements intake, a decision engine that cites its evidence, and code generation that ends in something you can actually deploy — including on-premise, inside a customer VPC, or fully air-gapped.

pip install fde-framework
fde start acme --statement "Extract fields from supplier invoices."
fde ask acme --role admin        # role-scoped discovery interview
fde architect acme               # topology + chosen approaches (rationale lands in ARCHITECTURE.md)
fde build acme --out project     # refuses: seven gates guard the build
# ...verify data access, capture the baseline, name the eval owner (each gate prints its remedy), then:
fde build acme --out project     # code + evals + deploy assets + runbook

That refusal at the end is the product working: no baseline, no verified data access — no build. The remedies ship with every gate.

What it does

How it fits together

Discovery narrows an answer space; gates decide whether building is honest yet; the decision engine picks the simplest applicable approach per component and cites why; emit writes a project whose exam fails until it is truly implemented. The full design is in ARCHITECTURE.md.

Who this is for

• Forward deployed engineers and solutions engineers delivering AI systems inside client environments, where discovery, deployment constraints and handover matter as much as the model.
• Consultancies and AI delivery teams who want engagement knowledge to compound — every retrospective can enter a shared corpus as an anonymised case.
• Platform teams shipping LLM systems into regulated, on-premise, or air-gapped environments, where "call a hosted API" is not an option and the evaluation has to run where the system runs.

Status: built, demonstrated, unproven

Three different claims, and the differences are the point.

Demonstrated: three complete engagements have run end to end on real data, all public with every refusal preserved. fde-demo-receipts — 626 scanned receipts through gates, build, and an agent-driven implement loop (fde implement, graded against held-out cases the agent never sees) whose holdout refused an overfit implementation and whose measured plateau flipped the design from rules to a model, reason on the record. fde-demo-complaints — 2,034 real consumer complaints through the decision shape: the exam refused ambiguous ground truth before it existed, the agent posture was decided from the facts, and the loop finished green with the holdout passing — the framework's first. fde-demo-rfc-qa — freeform QA over 58 real RFCs: 100% recall@10 on real queries, a green loop, and then the calibration gate refusing its own judge exactly as the prediction published beforehand said it would (73.7% agreement, refused; the judge's 89.5% was 26 points of flattery over the hand-graded 63.2%). Six of this framework's releases (0.1.6–0.1.11) shipped from what these runs found.

Built: the pipeline exists end to end — intake (prose, documents, sample pairs, role-scoped interview, hardware scan) → fact log with provenance → permutation space → seven gates → decide → architect → build (code, evals, deploy and ops assets, RISKS.md, COMPLIANCE.md) → retro and case capture. Overrides are honoured on the next run, trigger observations feed calibration, and a reviewed case can enter the corpus. 890+ tests; four fresh-eyes review rounds, every finding resolved and the fix pinned as a regression test; CI gates on the suite, lint, and a sanitisation scan of the tree and its history; the evidence corpus is anchored to publicly documented production deployments; every decision is reproducible from its inputs.

Unproven means exactly one thing: no production engagement has yet run through it start to finish. The proof loop is wired and waiting — fde retro captures measured outcomes, human-reviewed cases grow the corpus, and rule revision begins when there are retrospectives to revise against, not before. Pretending earlier would be borrowing rigour rather than having it.

What that means for you today: the generated projects are real and the decisions are defensible, but you are an early adopter, not a reference customer — and the first measured retrospectives will be worth more to this framework than any feature.

Two rules

Every intake surface — prose, interviews, scans, sample pairs, the client's existing stack — emits facts into one profile, and two rules make that safe. Arrival order never decides anything — provenance does, and it is dimension-dependent: a measurement outranks anything said about the environment, while a stated requirement outranks a measurement, since you cannot detect a latency budget. And two people disagreeing is a finding, not a conflict to resolve; the dimension is left unresolved and reported, because the gap between what a sponsor believes and what a user experiences is usually the most valuable thing discovery produces.

The full pipeline those rules feed — space pruning, decomposition, the seven gates, decision, emission — is in ARCHITECTURE.md.

What it will not do

Recommend a tool because it is fashionable. plain-python is a first-class option in every pattern, and the schema rejects any pattern that omits it. A two-step linear workflow should not get a graph framework, and the framework has to be able to say so.

Reach for a container by default. Deployment substrate is a ladder from a systemd unit through to Kubernetes. For a single-node on-prem deployment serving one model to a team with no container competence, rung zero is the right answer.

Assume a jurisdiction, sector, topology or stack. Everything is a discovered parameter with a sensible default. A locale pack may pre-set values on dimensions that already exist and attach obligations to the build; it may never introduce a new dimension, because geography changes what you must produce, not how you decide.

Guess. Every claim carries evidence, a date, and a re-derivation rule. Where the framework has no evidence, it says so — undecidable components ship as modules that raise with the reason attached, never as silent gaps.

Install

Prerequisites: Python 3.11+.

pip install fde-framework          # the registry ships inside the wheel
fde start acme --statement "..."   # works from any directory

Extras: pip install "fde-framework[documents]" for PDF/docx intake, [llm] for the hosted-model reader path.

Or from source (contributors — a local ./framework outranks the packaged copy):

git clone https://github.com/atulkapoor/fde-framework.git
cd fde-framework
python3 --version   # must say 3.11+; an older python3 makes pip backtrack for ages instead of failing fast
python3 -m venv .venv && .venv/bin/pip install -e ".[dev,documents]"

Or with uv: uv venv && uv pip install -e ".[dev,documents]"

Optional extras

The core needs none of them: plain-text intake, the decision engine and the build work with zero optional dependencies, which is deliberate — an air-gapped install should not drag in what it will not use. A missing reader refuses by name and says exactly what to install.

File types

Try it

fde start acme --statement "Extract fields from supplier invoices."
fde ask acme --role admin        # bare names resolve to ./engagements/acme
fde status acme                  # gates, gaps, disagreements
fde architect acme               # the design, with rationale
fde build acme --out project     # refuses until gates clear

fde scan acme                    # what this hardware runs
fde cost --requests-per-day 500000 --model-b 70   # dated fleet sizing

fde kb validate   # parse and cross-link the registry
fde kb gaps                        # what the corpus is missing
fde kb sweep                       # profiles no approach can serve

kb validate is strict, because CI runs it and a warning nobody reads is not a check. --lenient exists for the hour when you are mid-way through authoring content and the links do not resolve yet.

A complete worked engagement — real transcript, synthetic client — lives in examples/invoice-extraction.

What a build emits

project/
├── app/                  # components, pipeline, controls, boundary check
│   ├── components/       #   implementations or honest scaffolds — never silent gaps
│   ├── pipeline.py       #   topological order; approval gates before anything mutative
│   ├── controls.py       #   fail-closed gates & critics — when anything mutative was decided
│   ├── boundary.py       #   imported at startup when data may not leave
│   ├── contract.py       #   RefusedInput: forbidden input is refused, never guessed at
│   └── llm.py            #   the one model touchpoint — when a decision needs a model (boundary-gated)
├── evals/                # golden / edge / adversarial sets from the client's own pairs
│   ├── harness.py        #   fails CI until implemented; judge-based when the evaluation decided judged
│   ├── retrieval.py      #   recall@10/50 of the retrieval layer alone — when retrieval answers ranked queries
│   ├── acceptance.md     #   blind UAT protocol for the client's own judges
│   └── load.py           #   p95 against the stated budget (when one was stated)
├── tests/                # the deliverable's own model-free smoke: contract, fence, empty-exam refusal
├── deploy/               # the substrate that was earned, its full install path, + TEARDOWN.md for all of it
├── ops/                  # runbook (first-five-minutes commands up top), diagnosis walk, SLOs, rollback
├── ARCHITECTURE.md       # scope read-out, decisions, tools & alternatives, agent posture
├── RISKS.md              # every waived gate and overridden recommendation
└── COMPLIANCE.md         # jurisdiction obligations, when a locale pack was applied

Emitted quality is a pinned property, not a promise: the framework's own test suite emits projects across representative architecture shapes and holds every emission to the operational contract — every environment variable the code reads is documented, everything the systemd unit demands is created by a shipped installer, CI has a lane that goes green without a model, the smoke test passes on a fresh emission, the code is lint-clean, and the payload path chains no deployment steps. A quality finding lands there as a check before it lands anywhere as a fix (tests/test_acceptance.py).

The full lifecycle, copy-paste

Everything below runs from an empty directory after pip install fde-framework:

fde start acme --statement "Extract fields from scanned supplier invoices; \
data cannot leave; 200,000 documents, 8,000 verified; a person is waiting."
# plays back the typed facts it read, and the three questions worth asking next

fde ask acme --role eval_owner       # answer what discovery still needs
fde status acme                      # facts by scope, gates, % settled

cat > baseline.yaml <<'YAML'
volume: {value: 20000, unit: docs/month, definition: invoices received by AP}
cycle_time_per_unit_seconds: {value: 300, unit: s, definition: arrival to posted}
labour_hours_per_week: {value: 35, unit: h/week, definition: AP team keying time}
rework_rate: {value: 0.1, unit: ratio, definition: entries corrected after post}
exception_rate: {value: 0.07, unit: ratio, definition: routed to a human queue}
error_rate: {value: 0.04, unit: ratio, definition: wrong amount or vendor posted}
business_metric: {value: 9, unit: days, definition: mean days payable outstanding}
sampled: {n: 40, method: random invoices across two months}
YAML
fde baseline acme --file baseline.yaml
fde data-access acme --note "read replica returned 14 real rows"
fde security-review acme --note "client infosec walked the data paths"
fde ask acme --role eval_owner       # or: fde waive acme client_readiness --reason "..."

fde build acme --out project         # refuses until the gates truly pass
python project/evals/harness.py      # red: empty until pairs are seeded, then red until implemented -- that's the exam
fde implement project                # drive a coding agent until it's green

Python API

The CLI is a thin layer; everything is importable. The registry loads from the installed wheel, so this runs anywhere:

from fde.architect import architect
from fde.intake.prose import parse_prose
from fde.models.profile import Profile
from fde.registry import default_root, load_registry

registry = load_registry(default_root())

profile = Profile()
profile.ingest(parse_prose(
    "500,000 scanned invoices; data cannot leave; 10,000 verified; "
    "a person is waiting; structured records out.", registry))

design = architect(profile, registry)
print(design.topology)                    # customer-vpc
for component, decision in sorted(design.decisions.items()):
    if decision.approach:
        print(component, decision.approach, decision.rationale)

Every decision object carries its rationale and its rejected alternatives — the same receipts the emitted ARCHITECTURE.md prints.

Common commands

Why not RAGAS or TruLens?

Deliberately. Their headline metrics are judge-scored, and an uncalibrated judge is the failure mode this framework has now measured first-party: a local judge inflated results by 26 points before the calibration gate refused it (the run is public). The emitted evals are seeded from the client's own verified examples, stdlib-only — they run inside an air gap and hand over with zero dependencies — reference-based with discrete verdicts, and no judged number is quoted before the judge beats a human-agreement bar against the named eval owner. If your team wants RAGAS or TruLens dashboards alongside, point them at the same golden pairs — the JSONL is the same shape. The gate a delivery is graded on stays calibrated, or stays silent.

Troubleshooting

no registry here — you passed --registry/--root at a directory that holds no registry. Drop the flag (the corpus ships inside the package) or point it at the framework/ of a source checkout.

build refuses with gates listed — that is the point. fde status names each gate and its remedy; soft gates take fde waive <gate> --reason, data access takes only credentials that returned real rows.

A component module raises UndecidedComponent — nothing could be decided for it; the raise message names the unanswered question. Answer it and rebuild — holes are loud here, never silent.

fde kb sweep shows undecidable profiles — some are honest contradictions (data cannot leave + nobody to operate). fde architect on that profile names the conflicting facts.

The evaluation harness fails CI — it evaluates the emitted pipeline; it fails until the components are implemented end to end. A gate that cannot say no is not a gate.

Design

The registry under framework/ is data, not code. Adding a stack, a pattern, a locale or a case is a file, never a change to src/. That constraint is enforced by tests, and it is the thing that keeps the framework general rather than gradually becoming one consultancy's tooling.

Patterns are separated from stacks because patterns are stable for years and the libraries implementing them churn in months. A pattern says what; one realization per stack says how, as a template plus a claim to satisfy a typed interface. Swapping the stack changes the emitted code and not the architecture, and there is a test asserting exactly that.

FAQ

What is a Forward Deployed Engineer? An engineer who works inside a client's environment to deliver a working system — part solutions architect, part implementer, part translator between what a client asks for and what they need. The role is common in AI companies shipping into enterprises; this framework encodes the craft of running such an engagement well.

Does the framework itself call an LLM? No. Intake parsing, decision-making and code generation are deterministic — the same profile always produces the same project, so a diff between two builds means a decision changed. LLMs appear in the generated systems where the profile justifies one, behind interfaces that make them swappable.

Does it work air-gapped? Yes, by design. The framework runs from plain files with no server or network dependency, the registry knows which stacks can run inside an air gap, and the offline-evaluability gate refuses a design whose metric cannot run where the system runs.

How is this different from a project template? A template gives everyone the same starting point. This decides — from discovered facts, with cited evidence and named rejected alternatives — and then generates. Two clients with different constraints get different architectures, and the document explains why.

How does it improve over time? Every engagement captures its overrides (when the FDE chose differently), trigger calibration (did predicted graduations fire?), and an anonymised case. Cases enter the corpus only after human sanitisation review; rules are revised only when a corpus of outcomes exists — capture now, revise later, never pretend.

What does "self-evolving" mean here, concretely? Three recorded signals — overrides, trigger observations, case outcomes — and a human-gated path from a retrospective into the shared knowledge base. Nothing in framework/ changes by itself; the corpus grows, and revision against it is a deliberate, evidenced act.

Privacy

Everything runs from plain files on your machine. The default path makes no network calls, has no telemetry, and never transmits engagement content anywhere — it works on a plane and inside an air gap, and a text editor is always a legal way into its state. Discovery, decisions, and builds never call an LLM.

Four commands are the deliberate exceptions — each opt-in, each governed by the boundary doctrine (hosted models refused unless the engagement states data may leave; local endpoints always allowed):

• fde frame --reader llm — a model proposes facts, at the weakest provenance
• fde kb suggest — mines a brief for recogniser gaps, proposing (never applying) vocabulary
• fde implement — drives a coding agent you name
• the judge-based eval harness in generated projects whose evaluation decided judged (LLM_ENDPOINT, hosted path refused inside a boundary)

Nothing calls a model silently, and fde scan recommends a local model sized to your hardware so none of it needs to leave the machine.

Engagement directories (client facts, baselines, gate state) are excluded from version control by construction and enforced in CI — along with credential patterns, personal-data patterns, and a check that no unreviewed case can ever be committed.

Team setup

The registry is the shared asset; engagements are private working state.

• Share framework/ — fork or clone it as your team's knowledge base. Every dimension, approach, stack and case is a markdown file; review registry changes like code, because they decide architectures.
• Never commit engagements/ — client facts stay local. The repository's own .gitignore and CI sanitisation gate enforce this shape; keep it in yours.
• Grow the corpus deliberately — fde retro captures a case, fde kb ingest-case lands it as sanitization: pending, a human reviews it for anything identifying, and only reviewed cases can be committed. One reviewed case per delivered engagement compounds fast.

Roadmap

• Rule revision from outcomes — capture is wired end to end; revision deliberately waits for a corpus of measured retrospectives rather than pretending a handful is evidence.
• More locale packs and stacks — both are data; contributions enter against CONTRIBUTING.md's contract (and the code of conduct).
• Language, channel, and device axes — six of twenty industry test statements named regional languages, low bandwidth, or basic devices; the honest wiring (per-language evaluation, SMS/IVR serving approaches, safeguarding governance) is a corpus milestone, not a checkbox.
• Scale words — "millions of applications", "tens of millions of players": refusing to guess a number from "millions" is doctrine, and a better answer than refusal is still owed.
• Capability-verb extraction — "update the claims system of record" implies an integration no regex can count; the LLM reader proposes facts today, and component hints are its natural next job. The honest gaps list lives in the tool itself: fde kb gaps and fde kb sweep report what the corpus is missing and which profile shapes no approach can serve yet.

Documentation

Development

Set up as in Install → from source (python3.11+), then:

.venv/bin/pip install -e ".[dev,documents]"
.venv/bin/pytest -q          # 890+ tests, < 60s
.venv/bin/ruff check src tests

The registry is data: most contributions are a markdown file in framework/ plus a test that pins the behaviour. CI additionally runs a sanitisation sweep over the tree and history.

Community

Questions and engagement war stories → Discussions. Bugs and corpus gaps → issues (the forms ask for evidence, the way the framework does). Conduct → CODE_OF_CONDUCT.md.

License

Apache 2.0 — chosen for the explicit patent grant, because enterprise legal review is a real gate for the audience this is for.

Contributing

See CONTRIBUTING.md. The short version: contributions enter against a contract, and client material never enters this repository — only patterns re-expressed in the framework's own words. Sanitisation is enforced in CI: allowed paths only, history checked, credential and personal-data patterns, and no unreviewed case can be committed.