[SPIKE]: Investigate CPEX plugin framework compatibility with MCP SDK 2026-07-28

[cafalchio]

🧭 Type of Feature

• Developer tooling or test improvement
• Other (Compatibility investigation / spike)

🧭 Epic

Title: CPEX Plugin Framework MCP SDK Compatibility Investigation
Goal: Determine if the current CPEX plugin framework is compatible with the MCP SDK version 2026-07-28 and identify any breaking changes or required updates.
Why now: The MCP SDK 2026-07-28 may introduce changes that affect plugin framework integration. We need to assess compatibility before upgrading or making architectural decisions.

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🧑🏻‍💻 Investigation Scope

As a: Platform developer
I want: To understand CPEX compatibility with MCP SDK 2026-07-28
So that: We can plan necessary updates and avoid breaking changes in production

✅ Investigation Deliverables

• Review MCP SDK 2026-07-28 changelog and breaking changes
• Test current CPEX plugin framework against new SDK version
• Document any incompatibilities or deprecated features
• Identify required code changes (if any)
• Assess impact on existing plugins (native and external)
• Provide recommendation: compatible as-is, minor updates needed, or major refactor required

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📐 Investigation Areas

Key areas to examine:

1. Hook Interface Changes

   • Verify prompt_pre_fetch, prompt_post_fetch, tool_pre_invoke, tool_post_invoke, resource_pre_fetch, resource_post_fetch signatures
   • Check payload and result types

2. External Plugin Protocol

   • STREAMABLEHTTP and STDIO transport compatibility
   • Required tool signatures (get_plugin_config, hook tools)

3. Plugin Configuration Schema

   • Verify plugins/config.yaml structure compatibility
   • Check kind, hooks, mode, priority fields

4. Framework Dependencies

   • Review cpex package version requirements
   • Check for deprecated imports or APIs

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🔗 MCP Standards Check

• Review MCP SDK 2026-07-28 release notes
• Test against MCP specification compliance
• Document any deviations or required adaptations

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📓 Additional Context

• Current CPEX framework: cpex package (ContextForge Plugin Extensions)
• Plugin directory: plugins/ with 42+ plugin implementations
• Configuration: plugins/config.yaml (Jinja-enabled)
• Related docs: plugins/AGENTS.md, plugins/README.md

Success Criteria:

• Clear compatibility assessment documented
• List of required changes (if any) with effort estimates
• Recommendation for next steps (upgrade path or maintain current version)