ADR-008: RAG-Only Plugin Platform + Frontend Scope Lock

• Status: Accepted
• Date: 2026-07-14
• Context: Close dead hooks, Core industry coupling, and thin plugin DX while keeping EagleRAG a pure RAG data layer (not a business Agent platform).

Decision

1. Product red line: EagleRAG does ingest / retrieve / assemble-context / admin-metadata only. Domain plugins improve recall quality; they must not grow Agent behavior or side-effect MCP tools.
2. Hot-path hooks: PARSE, CHUNK, and QUERY_ASSEMBLE are invoked on ingest/query paths via eagle_rag/plugins/hotpath_hooks.py.
3. Core decoupling: Per-plugin knobs under settings.plugins.options[<namespace>]. Core source_type.rules default empty. Reconstruct fans out specialized collections from the plugin manifest.
4. MCP: Explicit register_mcp_tools(); RAG-only naming (assert_rag_only_tool_name); G3 namespace filter.
5. Frontend scope: Built-in UI = Core knowhere + pixelrag hybrid showcase. Domain plugins = backend + MCP only.
6. SDK: plugins/_template/ + Chinese authoring guide under docs/zh/guides/.

Consequences

• New verticals ship as module + profile + MCP without Core edits or frontend.
• Documentation separates Core UI vs domain MCP.