@tallwatch/contracts

The shared Zod-schema layer. Every cross-boundary payload (REST, queue, webhook, MCP) is defined here exactly once; TS types are inferred via z.infer.

Why a separate package

• The api validates inbound; the web/probers/workers infer outbound TS types. Single source of truth, renaming a field is one change, tsc flags every consumer.
• Web depends on @tallwatch/contracts (zero runtime DB code) so the bundler never accidentally pulls in pg or Drizzle.
• Terraform provider + MCP server both codegen from these same schemas (zod-to-openapi, MCP tool spec generation).

Layout

src/
├── common.ts      # Region, ErrorClass, ProbeStatus, Uuid, IsoTimestamp
├── monitors.ts    # MonitorConfig discriminated union + Monitor wire type + Create/Update/List
├── monitors/probes.ts # ProbeJob (api → prober), ProbeResult (prober → api)
├── incidents.ts   # IncidentEvent (source of truth), Incident (projection), Ack/Resolve
├── alerts.ts      # AlertChannel, EscalationPolicy, OnCallSchedule, OnCallOverride
├── webhooks.ts    # Canonical outbound WebhookPayload (the default template substitutes against this)
└── index.ts       # Re-exports everything

Usage

// In /api, validate inbound
import { CreateMonitorSchema } from "@tallwatch/contracts";
const parsed = CreateMonitorSchema.parse(req.body);

// In /web, typed forms
import type { Monitor, CreateMonitor } from "@tallwatch/contracts";

// In /probers, typed jobs and results
import { ProbeJobSchema, ProbeResultSchema } from "@tallwatch/contracts/probes";