@toolgrain/protocol

Public exports and behavior of @toolgrain/protocol.

Wire types, protocol constants, and provenance. This package has no runtime dependencies and does not provide validators, dispatchers, transports, or a server implementation.

Revision constants

import {
  PROTOCOL_VERSION,
  LEGACY_PROTOCOL_VERSION,
  SUPPORTED_PROTOCOL_VERSIONS,
  type SupportedProtocolVersion,
  type ProtocolResponse,
} from "@toolgrain/protocol";

PROTOCOL_VERSION is "2026-07-28". LEGACY_PROTOCOL_VERSION is "2025-06-18". SUPPORTED_PROTOCOL_VERSIONS is their readonly tuple, and SupportedProtocolVersion is its element union. The upstream root also exports its original LATEST_PROTOCOL_VERSION constant.

ProtocolResponse is the shared response-envelope union used by transport contracts; LegacyJSONRPCErrorResponse models legacy errors, including null IDs that the older upstream schema cannot express.

Wire definitions

Modern upstream definitions are exported unchanged from the package root, including request/result/notification types, JSON-RPC envelopes, implementation/capability types, tool/content/resource/prompt shapes, and protocol error constants. Types describing methods do not mean Toolgrain’s server implements those methods. Consult the supported feature scope.

Legacy definitions are a separate entry point:

import type { Tool, CallToolResult } from "@toolgrain/protocol";
import type * as Legacy from "@toolgrain/protocol/2025-06-18";

Use the revision-specific type rather than coercing one era’s envelope into another. The complete wire contract is the unchanged modern schema source and legacy schema source, which are the authoritative reference for all upstream exports.

Provenance

Both schemas are pinned to upstream commit 271ecc9accafdd9b83a3c869fa67c22953b2af80. Revision folders retain their checksums, provenance, and upstream license. Corresponding JSON schemas are test-only conformance fixtures, not runtime exports or files copied to dist.

MCP runtime validation remains in @toolgrain/mcp. Import wire types directly from protocol; MCP does not re-export them. See licensing for mixed-content notices and update boundaries.