JSON Schema Output Guard · AI Engineering

A schema preflight and bounded-repair receipt for model output contracts.

Node 22.18+ and Python 3 for the grader; TypeScript unions, recursive functions, JSON and async callbacks. The core uses standard libraries. The grader checks your selected workspace; it never fills in missing behavior from the reference.

Build and run your version

From the repository root, initialize once. A fresh starter fails intentionally.

bash

python3 scripts/project_test.py json-schema-output-guard --init learning-artifacts/json-schema-output-guard
python3 scripts/project_test.py json-schema-output-guard --stage 1 --path learning-artifacts/json-schema-output-guard --strict

Implement each stage, then run the cumulative grader and the supplied input driver:

bash

python3 scripts/project_test.py json-schema-output-guard --all --path learning-artifacts/json-schema-output-guard --strict
cd learning-artifacts/json-schema-output-guard
node cli.ts --schema samples/schema.json --attempts samples/attempts.json --output guard.json --html guard.html

The driver and offline samples are provided scaffolding. Its imports resolve to your implementation. Public input types and function signatures live in the starter and API contract.

Inspect the reference separately

From the repository root:

bash

python3 scripts/project_test.py json-schema-output-guard --all --solution --strict
cd projects/json-schema-output-guard/solution
node cli.ts --schema samples/schema.json --attempts samples/attempts.json --output guard.json --html guard.html

Observe the change

Attempt 1 rejects confidence 1.5 at $/confidence. Attempt 2 accepts confidence 0.8. An unsupported keyword in an absent optional property now fails during schema preflight.

Edit a copy of the sample and rerun the command. Keep the input beside the output so someone else can reproduce the result; the supplied samples are authored teaching data.

Integration and limits

Call guard(raw,schema) at the application boundary, or repair(generate,schema,maxAttempts) where generate receives structured Issue[] and a one-based attempt number.

This is an explicit JSON Schema subset. $ref, format and combinators are rejected. Schema acceptance does not establish whether an answer is factually correct. Recorded repair is not a live model call.

Stages

Primary references

JSON Schema validation vocabulary Node TypeScript execution