v0.1.6

🌟 Release Highlights

v0.1.6 delivers an important agent reliability fix, MCP spec compliance improvements, and developer experience enhancements that make MCP Gateway more robust and easier to work with.

🐛 Critical Fix: Agent Infinite Loop Resolved

• Payload threshold increased to 512KB (#1441): Agents were entering infinite retry loops when attempting to read payload files that weren't accessible inside their containers. The payload size threshold now defaults to 512KB (up from a lower value), significantly reducing unnecessary payload file references.
• Payload path prefix configuration: A new --payload-path-prefix flag (and MCP_GATEWAY_PAYLOAD_PATH_PREFIX env var) allows remapping filesystem paths to client-accessible paths — enabling agents in containers to correctly resolve payload locations.

✨ What's New

• Custom server schema validation (#1312, #1400): MCP Gateway now validates custom server configurations against schemas per [MCP Spec §4.1.4]((spec.modelcontextprotocol.io/redacted), including strict HTTPS-only enforcement for custom schema URLs. Misconfigured servers are rejected at startup with clear error messages.
• Dev container support (#1434): A .devcontainer configuration is now included, making it easy to spin up a fully configured development environment in VS Code or GitHub Codespaces with a single click.

📚 Documentation

• Clarified the absolute path requirement for Docker volume mounts and documented the DOCKER_API_VERSION auto-detection behavior (with fallback to 1.44) (#1313).

🔧 Internal Improvements

• Expanded test coverage across launcher session management, DIFC labels, custom schema validation, sanitization, and Docker utilities.
• Added debug logging to MCP connection SDK wrappers and DIFC labels for improved observability (DEBUG=mcp:* or DEBUG=difc:*).
• Multiple code quality refactors: middleware deduplication, MCP connection file split by concern, and utility package consolidation.

🐳 Docker Image

The Docker image for this release is available at:

docker pull ghcr.io/github/gh-aw-mcpg:v0.1.6
# or
docker pull ghcr.io/github/gh-aw-mcpg:latest

Supported platforms: linux/amd64, linux/arm64

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For complete details, see the full release notes.

Generated by Release

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What's Changed

• Fix smoke-copilot: call Serena tools directly instead of inferring availability from mcp-inspect by @Copilot in #1249
• Copilot/remove serena activate project by @lpcox in #1259
• Copilot/debug language support tester workflow by @lpcox in #1264
• Copilot/compile language support tester smoke workflows by @lpcox in #1265
• [test] Add tests for launcher.GetOrLaunchForSession by @github-actions[bot] in #1291
• Update documentation for mount absolute path requirement and DOCKER_API_VERSION behavior by @claude in #1313
• Refactor: Extract wrapWithMiddleware helper to eliminate duplicate middleware chaining code by @claude in #1311
• Implement custom server schema validation (MCP Spec 4.1.4 compliance) by @claude in #1312
• Recompile language-support-tester workflow with latest compiler by @claude in #1314
• [test] Add tests for config.validateAgainstCustomSchema by @github-actions[bot] in #1334
• [test-improver] Improve tests for server tool_name package by @github-actions[bot] in #1335
• Eliminate duplicate sys tool metadata in registerSysTools() by @claude in #1349
• Refactor: Consolidate function clustering — Docker utilities, stdlib reimplementation, and string truncation by @claude in #1350
• [log] Add debug logging to difc/labels.go by @github-actions[bot] in #1369
• [test] Add tests for difc.labels (CheckFlow, ViolationError, Clone, Union) by @github-actions[bot] in #1370
• [test-improver] Improve tests for dockerutil package by @github-actions[bot] in #1371
• Refactor: split mcp/connection.go by concern, relocate misplaced server helpers by @Copilot in #1373
• [log] Add debug logging to MCP connection SDK method wrappers by @github-actions[bot] in #1394
• [test] Add tests for sanitize.SanitizeJSON by @github-actions[bot] in #1395
• Upgraded aws by @lpcox in #1399
• Enforce HTTPS-only for custom schema URLs (spec §4.1.4) by @Copilot in #1400
• refactor: eliminate duplicate StreamableHTTP session callback and SDK list method wrappers by @Copilot in #1403
• [test-improver] Improve tests for schema normalization package by @github-actions[bot] in #1406
• Fix Serena MCP language support tools unavailable in language-support-tester, smoke-copilot, and smoke-codex by @Copilot in #1401
• Add dev container configuration by @lpcox in #1434
• Fix agent infinite loop by increasing payload threshold to 512KB and adding path prefix configuration by @claude in #1441

Full Changelog: v0.1.5...v0.1.6