Ziola Provider Tools

Define, validate, and register structured browser tools for the experimental WebMCP API.

Repository: https://github.com/zioladev/provider-tools · License: Apache-2.0 · Zero runtime dependencies.

npm install @zioladev/provider-tools

Define your schema. Declare whether the tool reads or changes state. Provide the handler. The kit handles validation, registration, structured results, and runtime diagnostics.

import { defineProvider, mintConfirmationId } from '@zioladev/provider-tools';

const provider = defineProvider({
  name: 'sample-cafe',
  tools: [
    {
      name: 'get_menu',
      description: 'Returns the current café menu and prices.',
      effect: 'read',
      inputSchema: { type: 'object', properties: {}, additionalProperties: false },
      handler: async () => ({ menu: [{ id: 'latte', price: 4.75 }] }),
    },
    {
      name: 'place_order',
      description: 'Places an order for a menu item and returns a confirmation.',
      effect: 'state-changing',
      inputSchema: {
        type: 'object',
        properties: {
          itemId: { type: 'string', enum: ['drip', 'latte'] },
          quantity: { type: 'integer', minimum: 1, maximum: 20 },
        },
        required: ['itemId', 'quantity'],
        additionalProperties: false,
      },
      handler: async ({ itemId, quantity }) => ({
        executed: true,
        confirmationId: mintConfirmationId('ORDER'),
        data: { itemId, quantity },
      }),
    },
  ],
});

await provider.register();

That's the entire surface.

What the kit does for you

• Feature-detects the WebMCP runtime (document.modelContext, falling back to navigator.modelContext) and no-ops when absent — human visitors are unaffected.
• Validates definitions before registering: required inputSchema (supported subset), explicit effect, unique names (incl. a document-level registry).
• Validates and rejects input at call time against your schema — no silent coercion.
• Owns the result envelope — read handlers return plain data; the kit wraps it.
• Enforces structured execution evidence for state-changing tools ({ executed, confirmationId | error }) so consumers never misclassify an action.
• Isolates registration failures per tool and returns a structured RegisterResult.

What it does NOT do

No authorization, approval/binding, receipts, payments, cross-model conformance, or orchestration. This is the provider creation layer only. Those concerns live elsewhere by design — see docs/state-changing-tools.md.

Documentation

• Getting started
• Tool definitions
• State-changing tools & execution evidence
• Validation & error codes
• Browser support & runtime detection
• Real-browser acceptance plan (Chrome WebMCP)
• Canonical example: examples/vanilla-cafe

API reference

defineProvider(def: ProviderDef): Provider

Builds a provider. def is { name: string, tools: ProviderToolDef[] }.

ProviderToolDef:

field	type	notes
name	string	unique within the provider and the document registry
description	string	narrow, specific, agent-facing
effect	'read' | 'state-changing'	explicit; not inferred from the name
inputSchema	JSON-Schema object	required; supported subset; additionalProperties: false
handler	(input) => Promise<unknown> | unknown	receives validated input

Returns a Provider:

• validate(): ValidationReport — static checks without registering.
• register(): Promise<RegisterResult> — validate, detect runtime, register. Idempotent per document context.
• tools: WebMCPTool[] — the built, runtime-shaped tools.

mintConfirmationId(prefix?: string): string

Optional helper that returns a short, human-looking id like ORDER-4821. You may supply your own confirmationId instead.

Other exports

wrap, detectRuntime, validateInput, validateDefinition, validateExecutionResult, isExecutionResult, SUPPORTED_TYPES, CODES, and the full set of types (Effect, ExecutionResult, RegisterResult, RuntimeInfo, ValidationReport, …).

Requirements

• Zero runtime dependencies.
• Node.js ≥ 20 for development (tests use --experimental-strip-types).
• Targets Chrome builds exposing the experimental WebMCP surface (flag-gated or Origin-Trial-enabled). See browser support.

License

Apache-2.0 © Ziola. Source at github.com/zioladev/provider-tools. This is independent open-source tooling for the experimental WebMCP API; it makes no transaction-assurance, security, or conformance guarantees.