demystify-platform-contracts 0.2.0

Single source of truth for Demystify cross-cutting wire contracts (Python mirror): error taxonomy, domain events, canonical headers, key format/hashing, currency helpers, key-introspection models.

@demystify/platform-contracts / demystify-platform-contracts

The single source of truth for Demystify's cross-cutting wire contracts, shipped as one dual-language, independently-publishable leaf package:

• TypeScript — @demystify/platform-contracts (ESM, zod schemas, .d.ts)
• Python — demystify-platform-contracts (pydantic v2 models, src layout)

It depends on no module (modules/*) and only on zod (TS) / pydantic (Py), so any module can take it as a normal versioned dependency AND keep working when copied out standalone (see Extractability).

What it exports

Concern	TS	Python
Error taxonomy	ERROR_CODES, ERROR_TYPE_BY_CODE, errorEnvelope, makeErrorEnvelope	ERROR_CODES, ERROR_TYPE_BY_CODE, ErrorEnvelope, make_error_envelope
Domain events (11)	EVENT_TYPES, EVENT_TYPE_IDS, EVENT_DATA_SCHEMAS, eventEnvelopeSchema(type)	EVENT_TYPES, EVENT_TYPE_IDS, EVENT_DATA_MODELS, event_envelope_adapter(type), is_valid_event_envelope
Canonical headers	HEADERS, DEPRECATED_HEADER_ALIASES	HEADERS, DEPRECATED_HEADER_ALIASES
Key format & hashing	KEY_PREFIX, KEY_FORMAT_RE, isValidKeyFormat, hashKey, keyLast4	KEY_PREFIX, KEY_FORMAT_RE, is_valid_key_format, hash_key, key_last4
Money / currency	CURRENCY_EXPONENT, toMinorUnits, fromMinorUnits	CURRENCY_EXPONENT, to_minor_units, from_minor_units
Key introspection	introspectRequest, introspectResponse, AUTH_MODES, INTROSPECTION_CACHE_TTL_SECONDS	IntrospectRequest, IntrospectResponse, introspect_response_adapter, AUTH_MODES, INTROSPECTION_CACHE_TTL_SECONDS
Tracing (W3C)	TRACEPARENT_RE, isValidTraceparent, newTraceparent, childTraceparent, spanName, SPAN_ATTR_KEYS	same, snake_case

The canonical cross-cutting decisions these encode are documented in CONVENTIONS.md §14 and mirrored in docs/contracts/platform-conventions.md.

Usage

TypeScript

import {
  errorEnvelope,
  HEADERS,
  hashKey,
  eventEnvelopeSchema,
  toMinorUnits,
} from "@demystify/platform-contracts";

const tenant = req.headers[HEADERS.tenant]; // "x-dmstfy-tenant-id"
const atRest = hashKey(plaintextKey); // sha256 hex
const evt = eventEnvelopeSchema("extract.job.completed").parse(payload);
const minor = toMinorUnits(1.23, "USD"); // 123

Python

from demystify_platform_contracts import (
    ErrorEnvelope, HEADERS, hash_key, is_valid_event_envelope, to_minor_units,
)

tenant = request.headers[HEADERS["tenant"]]      # "x-dmstfy-tenant-id"
at_rest = hash_key(plaintext_key)                # sha256 hex
ok = is_valid_event_envelope("extract.job.completed", payload)
minor = to_minor_units(1.23, "USD")              # 123

Contract parity (fixtures)

TS and Python are kept in lock-step by shared JSON fixtures under fixtures/. Both test suites (test/*.test.ts, tests/test_*.py) load the same fixtures and assert: identical ERROR_CODES / EVENT_TYPES / HEADERS / CURRENCY_EXPONENT, identical hashKey output, and identical accept/reject behaviour for every envelope, introspection, key-format and money case. Add a case once in fixtures/; both languages must satisfy it.

Extractability

Modules depend on this package as a normal versioned dependency. To keep a module working when copied out standalone, either:

1. install the published contracts package (@demystify/platform-contracts / demystify-platform-contracts), or
2. use the module's existing vendored copies of the wire contracts under modules/dmstfy-<x>/docs/contracts/*.md (these stay in the tree).

To keep the vendored markdown from drifting, this package ships scripts/sync-vendored.mjs, which regenerates each module's docs/contracts/*.md from the canonical repo-root docs/contracts/ (one source of truth):

node scripts/sync-vendored.mjs           # write vendored copies
node scripts/sync-vendored.mjs --check   # CI: exit 1 on drift
node scripts/sync-vendored.mjs --module rag

Module agents run sync-vendored during adoption. It is intentionally not part of setup/test/build and is not run automatically here.

Make targets

make setup   # pnpm install + uv sync --extra dev
make lint    # eslint + prettier + ruff + ruff format --check + mypy
make test    # vitest run + pytest (tiers 1-2, offline)
make build   # tsup + uv build
make pack    # build + npm pack --dry-run + uv build

Version 0.2.0 · MIT. No infra, no docker, no network — pure offline leaf package.

Changelog

• 0.2.0 — Platform-layer version alignment: the whole @demystify/platform-* suite (contracts, observability, profiles, state) moves to 0.2.x together. No contract changes in this package vs 0.1.0; the bump keeps all platform packages on a single shared minor (see root COMPATIBILITY.md). Modules must depend on platform packages that share the same minor.
• 0.1.0 — Initial: error taxonomy, domain events, canonical headers, key format/hashing, currency helpers, tracing, key-introspection schemas.