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vinkius-labs/mcp-fusion

v3.19.6 Breaking

This release includes breaking changes for platform teams planning a safe upgrade.

Published 23d MCP Developer Tools
✓ No known CVEs patched
Read the diff → Tool health → What is this tool? →

✓ No known CVEs patched in this version

Topics

mcp mcp-framework mcp-server model-context-protocol

ReleasePort's take

Light signal
editorial:auto 13d

@vurb/core v3.19.6 optimizes HTTP transport with three performance wins: O(n)→O(1) session close via WeakMap, ~10x faster URL parsing, and integrated rate limiter pruning. Adds V8 isolate leak detector.

Why it matters: O(1) session close improves shutdown latency. URL parsing is 10x faster on V8, reducing per-request overhead. Integrated rate limiter pruning lowers memory churn. Test in dev; incorporate in next quarterly upgrade cycle.

Summary

AI summary

Fixed three HTTP transport performance bottlenecks and added a V8 isolate leak detector.

Changes in this release

Feature Medium

Added `FinalizationRegistry`-based V8 Isolate leak detector for SandboxEngine in initVurb().

Added `FinalizationRegistry`-based V8 Isolate leak detector for SandboxEngine in initVurb().

Source: llm_adapter@2026-05-21

Confidence: low

Dependency Medium

All @vurb/* cross-dependencies updated to ^3.19.6.

All @vurb/* cross-dependencies updated to ^3.19.6.

Source: llm_adapter@2026-05-21

Confidence: low

Performance Medium

Session close O(n) → O(1) reverse-lookup with WeakMap in @vurb/core HTTP transport.

Session close O(n) → O(1) reverse-lookup with WeakMap in @vurb/core HTTP transport.

Source: llm_adapter@2026-05-21

Confidence: high

Performance Medium

Removed hot-path URL constructor `new URL()` on every HTTP request in @vurb/core, ~10x faster on V8.

Removed hot-path URL constructor `new URL()` on every HTTP request in @vurb/core, ~10x faster on V8.

Source: llm_adapter@2026-05-21

Confidence: high

Performance Medium

Reaper-integrated rate limiter pruning active-session set during iteration in @vurb/core.

Reaper-integrated rate limiter pruning active-session set during iteration in @vurb/core.

Source: llm_adapter@2026-05-21

Confidence: high

Other Medium

Added 22 new regression tests covering all optimizations across @vurb/* packages.

Added 22 new regression tests covering all optimizations across @vurb/* packages.

Source: llm_adapter@2026-05-21

Confidence: low

Full changelog

HTTP Transport Performance Optimizations, Telemetry Coherence, ESLint Hygiene

Fixed

@vurb/core — HTTP Transport Performance Optimizations

  • Session close O(n) → O(1) reverse-lookuponclose handler replaced [...sessions.entries()].find() linear scan with a WeakMap<Transport, string> reverse index for O(1) lookup.
  • Hot-path URL constructor removednew URL() on every HTTP request replaced with String.indexOf('?') + slice() (~10x faster on V8).
  • Reaper-integrated rate limiter pruning — Active-session set built incrementally during reaper iteration instead of allocating a fresh new Set(sessions.keys()).

@vurb/core — Telemetry Timestamp Coherence

  • Single Date.now() capture in telemetry emitdurationMs and timestamp now derived from a single captured value.

@vurb/core — ESLint Hygiene

  • 24 auto-fixable lint problems resolved across 7 files (103 → 79 total).

Added

  • FinalizationRegistry-based V8 Isolate leak detector for SandboxEngine in initVurb().
  • 22 new regression tests covering all optimizations.

Changed

  • All @vurb/* cross-dependencies updated to ^3.19.6.

Test Suite: 331 files, 6,827 tests passing.

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About vinkius-labs/mcp-fusion

A TypeScript framework for building production-ready MCP servers with automatic tool discovery, multi-transport support (stdio/SSE/HTTP), built-in validation, and zero-config setup.

All releases →

Related context

Earlier breaking changes

  • v4.0.0 All packages now published under the `@mcpfusion` npm scope.
  • v4.0.0 GitHub repository renamed to vinkius-labs/mcpfusion; npm packages under @mcpfusion scope.
  • v4.0.0 All source code, documentation, CLI output, workflows, and npm packages now use the @mcpfusion scope.

Beta — feedback welcome: [email protected]