Migrate all three clients + core + test-servers from
@modelcontextprotocol/sdk@1.29 to SDK v2 (2.0.0-beta.4), keeping behavior
identical against legacy (2025-11-25) servers. Foundation for the SDK V2 +
New Spec stack.
Packages
- Split @modelcontextprotocol/sdk -> @modelcontextprotocol/client (Client,
transports, OAuth, error taxonomy, protocol types) + core (Zod schemas);
stdio -> client/stdio, Ajv -> client/validators/ajv. Test-servers ->
@modelcontextprotocol/server (+ server-legacy/sse). Deterministic import
rewrite (schemas -> core, everything else -> client); the codemod misroutes
client code to /server so it was not used for path routing.
- new Client(..., { versionNegotiation: { mode: 'legacy' } }) — nothing
2026-era goes on the wire.
Runtime (core/mcp/inspectorClient.ts)
- Error taxonomy: McpError -> ProtocolError, ErrorCode -> ProtocolErrorCode;
RequestTimeout -> SdkError/SdkErrorCode.
- Handlers take method strings; task methods (tasks/*, notifications/tasks/*)
use the 3-arg custom form (excluded from v2's spec-method set).
- Legacy tasks kept working (per project requirement): requestor tasks re-
implemented over raw client.request + explicit deprecated schemas;
experimental.tasks.callToolStream replaced by a local pollTaskToolCall
async generator (with _progressHandlers revival so task-execution progress
still reaches the caller). Receiver (server-initiated) tasks: the v2 Client
validates a sampling/elicit handler result and rejects the legacy { task }
response with -32602 — installReceiverTaskResponseBypass swaps the wrapped
entry in the private _requestHandlers map for the task-augmented branch so
{ task } reaches the wire (fixes server-initiated sampling-via-task).
- Pagination: list verbs use raw client.request({method}, List*ResultSchema)
for single-page behavior (v2's client.listX() auto-aggregate all pages).
Web / auth / apps
- Rename local JsonSchemaType -> InspectorFormSchema + add toFormSchema()
structural narrowing at the SDK-schema -> form boundary.
- ext-apps still peers on SDK v1: one compat boundary with documented casts
(remove when ext-apps#702 lands a v2 peer).
- OAuth provider saveClientInformation reconciled with v2's
OAuthClientInformationContext; InvalidClientMetadataError re-homed as a
local class (server-legacy/auth is not browser-safe).
- vitest.shared.mts dedupes @modelcontextprotocol/client+core to one copy so
vi.mock intercepts the SUT's import.
Accepted v2 behavior changes (per #1624 / spec §9.2): unknown-tool call
rejects with -32602; cancellation is stream-abort (no guaranteed
notifications/cancelled frame); output-schema strictness restored via the
Inspector's own Ajv check on the default path.
npm run ci green: validate (web 3087 / cli 212 / tui 274 / launcher 5),
coverage (>=90 per-file, all clients), smoke (launcher/cli/web), storybook
(410).
Closes#1624
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Stands up the type-only prerequisites for the v2 UX component
interfaces refactor per specification/v2_ux_interfaces_plan.md.
Phase 0.1 — MCP SDK dependency:
- Add @modelcontextprotocol/sdk ^1.29.0 and zod ^4.3.6 to both the
root package.json and clients/web/package.json so component files
can import Tool / Prompt / Resource / Task / LoggingLevel / etc.
directly from the SDK.
Phase 0.2 — Inspector wrapper-types module:
- Create core/mcp/types.ts mirroring the type-only subset of v1.5's
core/mcp/types.ts: MCPServerConfig (discriminated union), ServerType,
MCPConfig, ConnectionStatus, StderrLogEntry, MessageEntry (Date
timestamps, not ISO strings), FetchRequestEntry(+Base), ServerState,
and the *Invocation types. Adds v2-only wrappers
InspectorResourceSubscription and InspectorServerJsonDraft.
- Add core/mcp/taskNotificationSchemas.ts for the Inspector-owned
notifications/tasks/list_changed signal (not in the SDK).
- Add core/mcp/elicitationCreateMessage.ts re-exporting ElicitRequest
and ElicitResult plus an InspectorPendingElicitation interface for
typing the pending-queue.
- Add core/json/jsonUtils.ts for the shared JsonValue / JsonObject
types used inside core/mcp/types.ts.
- Copy v1.5's clients/web/src/utils/jsonUtils.ts (JsonSchemaType) and
schemaUtils.ts (AJV-backed validators) verbatim so SchemaForm can
switch off its local JsonSchema type.
- Copy v1.5's clients/web/src/lib/types/customHeaders.ts verbatim for
ServerSettingsForm and the experimental panel.
- Add clients/web/src/types/navigation.ts with InspectorTab (UI-routing
concept, lives with the web client rather than in core/).
- Wire tsconfig.app.json + vite.config.ts with the @inspector/core/*
path alias so component files can import from core/ without
relative-path hell.
Phase 0.3 — Vet (likely) hedges in v2_ux_interfaces.md:
- Follow-up sweep on commit 2ef257da. Replaces the remaining
useMcpClient references with useInspectorClient, ties pending
elicitation / sampling callbacks to the in-InspectorClient queue
rather than a non-existent useElicitation / useSampling hook,
corrects Task references to the SDK type (not an InspectorTask
wrapper), corrects log hook wiring to useMessageLog, and strikes
all remaining v2-only hooks with explicit "no v1.5 analog"
annotations. grep "likely" specification/v2_ux_interfaces.md now
returns zero results.
Phase 0.4 — Local-redeclaration inventory:
- specification/v2_ux_interfaces_phase_0_4_inventory.md enumerates
every ad hoc local type (JsonSchema, LogLevel, TaskStatus,
PromptItem, ResourceItem, ToolListItemProps, RootEntry, KeyValuePair,
inline ConnectionStatus / transport unions) that will be replaced
in Phases 1–4, including the file it lives in, every site that
re-imports it, and the SDK / wrapper type that replaces it. Intended
for the Phase 0 PR description and as a running checklist during
the refactor.
Build state: npm run build / lint / format:check all pass in
clients/web.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
cliffhall