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Merged
robfrank merged 3 commits into from
Apr 23, 2026
Merged

Improve MCP server: init instructions and helpful database error #3966

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520678a
improved MCP with available db list on unknown db targeted
Apr 19, 2026
85e00f8
Added init instructuctions in MCP
Apr 19, 2026
efc1437
refactor: centralize MCP database auth check in resolveDatabase
robfrank Apr 23, 2026
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Added init instructuctions in MCP
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@robfrank
CNE Pierre FICHEPOIL authored and robfrank committed Apr 23, 2026
commit 85e00f8f85118f7da2511d3b6f61b0f386994190
8 changes: 8 additions & 0 deletions server/src/main/java/com/arcadedb/server/mcp/MCPHttpHandler.java
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Expand Up @@ -125,6 +125,14 @@ private ExecutionResponse handleInitialize(final Object id) {
capabilities.put("tools", new JSONObject().put("listChanged", false));
result.put("capabilities", capabilities);

result.put("instructions",
"You are connected to an ArcadeDB multi-model database server. Follow these rules:\n"
+ "1. ALWAYS call list_databases first when you do not know the target database name. Never guess it.\n"
+ "2. Prefer Cypher (language: 'cypher') for graph queries unless SQL is explicitly requested.\n"
+ "3. Use the 'query' tool for read-only operations (SELECT, MATCH, RETURN) and 'execute_command' for writes (CREATE, INSERT, UPDATE, DELETE, MERGE).\n"
+ "4. Call get_schema before writing queries against an unfamiliar database to understand its types and properties.\n"
+ "5. If a query returns no results, verify the type/property names with get_schema before concluding the data does not exist.");

return jsonRpcResult(id, result);
}

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