---
summary: "mcp-ts-core ^0.9.6 → ^0.9.13: HTTP body cap, session-init gate, quieter 4xx logs, GET /mcp keywords; httpErrorFromResponse adoption; keyword additions"
breaking: false
security: false
---

# 0.1.21 — 2026-05-28

## Changed

- **`@cyanheads/mcp-ts-core`** `^0.9.6 → ^0.9.13` — adopted across seven patch releases:
  - **`MCP_HTTP_MAX_BODY_BYTES`** (0.9.13) — configurable inbound body cap; oversized requests rejected with 413 before the SDK parses the body. Default 1 MiB; set to `0` to disable.
  - **HTTP session-init gate** (0.9.10) — stateful HTTP mode now rejects non-`initialize` requests without an `Mcp-Session-Id` header with HTTP 400.
  - **`httpErrorHandler` log-level split** (0.9.10) — 401, 403, 400, 404 responses downgraded to `warning`; stack traces removed from expected client errors.
  - **`GET /mcp` keywords** (0.9.12) — `package.json` `keywords` now surfaced on the HTTP status endpoint alongside name/version/description.
  - 0.9.7–0.9.9, 0.9.11 — skill refreshes, `git-wrapup` skill, fuzz pre-parse fixes, `code-simplifier` skill, `biome` lint adjustment.
- **`pubchem-client.ts`** — `httpStatusToErrorCode` + manual `McpError` construction replaced with `httpErrorFromResponse` (framework util that classifies by status and body). Both `fetchJson` and `fetchBinary` error paths updated; fault message passed as `data.fault` alongside `data.url`.
- **`package.json` keywords** — added `typescript`, `bun`, `stdio`, `streamable-http` (surfaces on `GET /mcp` endpoint via 0.9.12 framework support).
- **`@biomejs/biome`** `^2.4.15 → ^2.4.16`.

## Skills

- **Skills synced** from `@cyanheads/mcp-ts-core@0.9.13` — refreshed `api-canvas`, `api-config`, `design-mcp-server`, `polish-docs-meta`, `release-and-publish`, `report-issue-framework`; added `code-simplifier`, `git-wrapup`; removed `migrate-mcp-ts-template`.