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Overview

This changelog tracks all notable changes to MCPJam Inspector. We follow Semantic Versioning and keep our changelog in the spirit of Keep a Changelog.

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Latest Releases

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2026-06-26

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Added

  • Compatibility destination — a new Inspector page that evaluates your connected MCP server against a catalog of AI hosts (Claude, ChatGPT, Cursor, Copilot, Codex, and others). Shows conformance gates, per-host findings split into Apps and Server lanes, and live widget rendering. Accessible from the left sidebar when a server is connected.
  • OTLP/OpenInference trace export — export eval run traces as OTLP JSON from the run detail page. Compatible with Arize Phoenix, Datadog, and any OTLP-compatible observability backend. Supports exporting a single run or the whole project, with an opt-in to include content and artifacts.
  • @mcpjam/sdk/host-compat subpackage — the shared host-compatibility engine is now importable directly. Use deriveServerRequirements, evaluateHostCompat, evaluateAllHosts, scanWidgetSource, and detectHostCompatBridgeFromMeta to build your own compatibility checks in CI or custom tooling.

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Version 1.1.0

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Improved

  • Code Quality
    • Improved code consistency and maintainability

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Recent Updates

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Added

  • VS Code and Notion market hosts (@mcpjam/sdk minor)
    • VS Code (GitHub Copilot chat panel) is now a market host in the SDK’s host-compat catalog. It renders MCP UI inline and supports all display modes (inline, fullscreen, pip). Capabilities mirror the VS Code client template; updateModelContext and message are not advertised. Provenance: probe.
    • Notion is now a market host. It is a tools-only/headless client (no widget rendering) that supports protocol version 2025-11-25. Provenance: probe.
    • Both hosts are available via buildMarketHostProfiles() / evaluateMarketHosts() and carry logos in the inspector’s host-compat UI.
  • imageSupport dimension on all market hosts (@mcpjam/sdk minor)
    • Every market host now carries an imageSupport field on its HostCompatProfile describing how it handles MCP tool-result images.
    • Three image sources are tracked per host: toolImageContent (direct MCP image blocks), embeddedResourceImages (image blobs inside MCP resources), and resourceLinkImages (image links resolved via resources/read).
    • Each source records model (whether the image is passed to the model) and ui (whether the host UI renders it).
    • A single placement value ("inline" | "collapsed" | "none") describes where rendered previews appear in the host UI.
    • New exported types: HostImageSupport, ImageSourceSupport, ImagePlacement from @mcpjam/sdk/host-compat.
    • New capability matrix: MCP_APPS_VSCODE exported from @mcpjam/sdk/host-compat.

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Changed

  • Stateless MCP protocol version updated to 2026-07-28 RC
    • The stateless transport protocol version has been updated from the retired DRAFT-2026-v1 placeholder to the upstream RC literal 2026-07-28, matching the canonical pin in modelcontextprotocol/main.
    • The protocol version picker in the inspector UI now shows Latest (2025-11-25) and 2026 RC (2026-07-28) instead of “Latest” and “Draft”.
    • The SDK constant STATELESS_DRAFT_2026_V1 has been renamed to LATEST_STATELESS_PROTOCOL_VERSION and now equals "2026-07-28".
    • Migration required: If you had servers pinned to DRAFT-2026-v1, you must re-select the protocol version in the inspector UI. Stored DRAFT-2026-v1 pins are rejected by spec-conforming servers with a -32004 UnsupportedProtocolVersionError.

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Added

  • OAuth Protocol 2025-03-26 Support
    • Added support for original MCP OAuth specification (2025-03-26)
    • Direct RFC8414 discovery from MCP server base URL with fallback endpoints
    • PKCE required for all clients
    • DCR and pre-registered client registration strategies
  • OAuth Debugger Enhancements
    • Edit Config button to modify server settings without reconnecting
    • Copy logs feature with guide and raw formats for debugging
    • Deprecated transport detection with migration guidance for HTTP+SSE servers
    • RFC 8707 compliant resource URL canonicalization
  • GPT-5 Model Support
    • Added support for GPT-5 model variants: gpt-5, gpt-5-mini, gpt-5-nano, gpt-5-chat-latest, gpt-5-pro, gpt-5-codex
    • Organization verification notice for GPT-5 access

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Improved

  • OAuth Flow
    • Refined diagram focusing and zoom behavior for better step visualization
    • Improved error handling for expected 4xx responses during transport detection
    • Enhanced header merging in OAuth state machines across all protocol versions
  • Error Handling
    • Enhanced streaming error handling in chat interface
    • Errors now display as inline alerts instead of failing silently
    • Better error messages from AI providers

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Version 1.0.0

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Added

  • MCP Server Connection Management
    • Support for STDIO, SSE, and Streamable HTTP transports
    • Multi-server connection support
    • Real-time connection status monitoring
  • LLM Playground
    • OpenAI integration (GPT-3.5/4)
    • Anthropic Claude integration (Claude 2/3)
    • DeepSeek AI support (DeepSeek R1)
    • Ollama local model compatibility
    • Interactive chat interface with streaming responses
  • Tools & Resources Testing
    • Tool execution and validation
    • Resource schema verification
    • Prompt testing interface
    • Real-time parameter validation
  • OAuth 2.0 Testing
    • Guided OAuth flow setup
    • Token management
    • Scope verification
    • Refresh token handling
  • MCP Evals
    • Automated compliance testing
    • Custom evaluation framework
    • Test result reporting
    • Performance benchmarking
  • Developer Tools
    • Comprehensive logging system
    • Request/response tracing
    • Error reporting and analysis
    • Performance monitoring

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Improved

  • Enhanced UI/UX with modern design
  • Better error messages and debugging support
  • Optimized performance for large MCP responses
  • Improved documentation and examples

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Fixed

  • Various bug fixes and stability improvements
  • Memory leak fixes in long-running sessions
  • Edge cases in MCP protocol handling

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Coming Soon

We’re actively working on new features and improvements:
  • Enhanced evaluation templates
  • More LLM provider integrations
  • Advanced debugging tools
  • Performance analytics dashboard
  • CI/CD integration support

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Stay Updated

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Reporting Issues

Found a bug or have a feature request? Please open an issue on GitHub.