Use for Microsoft Fabric Eventstream — the streaming-ingestion item routing CDC / Event Hubs / Kafka / IoT / HTTP / MQTT events into Lakehouse, Eventhouse, Activator, or derived streams, and how external apps produce events to a schema-associated custom endpoint. Covers source connectors (Azure SQL / SQL MI / PostgreSQL / MySQL / MongoDB / Cosmos DB CDC, Mirrored DB Delta CDF preview, Event Hubs / IoT Hub / Kafka / MSK / Confluent / Kinesis / Service Bus / MQTT / HTTP / Solace), DeltaFlow analytics-ready CDC (auto-table + schema evolution), Activator destination + in-Eventstream `Set Alert` flow, three workspace-monitoring KQL tables (`EventStreamNodeStatus`/`EventStreamMetrics`/`EventStreamErrorMetrics`, ~6h status lag) + republish-on-enable, mTLS Key Vault on Kafka, custom-endpoint CloudEvents producer format (binary mode — `cloudEvents:` app properties, `dataschema` version routing), and gotchas (republish required, 6h status lag, filter by ArtifactId not name, CloudEventPropertyMissingException).
Use when troubleshooting Microsoft Fabric — common errors: 401 (wrong token audience), 403 on Power BI API (Viewer role), 404 EntityNotFound on getDefinition (permissions masquerading), PowerBIEntityNotFound from pipeline/Variable Library (logicalId vs runtime ID confusion), Login failed (wrong Initial Catalog), 24556/24706 snapshot conflict, nvarchar/datetime/money errors (Warehouse unsupported types), COPY INTO auth, MERGE/ALTER COLUMN failures, TMDL validation (tabs vs spaces, /// comments), DefaultJob jobType mistake, sqlcmd version, slow SQLEP (small files), notebook `400 exceptionCulprit:1` (bare-string cell source), plus the MUST/PREFER/AVOID best-practices summary.
Use for Microsoft Fabric Eventhouse / KQL Database. Covers connection (cluster URI via `kqlDatabases` REST, kusto.kusto.windows.net audience, az rest temp-file for `|` escaping), authoring (`.create-merge` for safe schema evolution, ingestion inline/set-or-append/from-storage `;impersonate`, streaming policy, CSV/JSON mappings, retention/caching/partitioning/merge policies, materialized views + update policies, external tables), OneLake-availability-ON constraints (add/delete column ✅ April 2026+; type/rename/RLS/deletes need availability off), per-KQL-database remote MCP server (http, read/query auth, not in global MCP template), 4-role permissions (viewer/user/ingestor/admin), KQL query patterns (time-filter-first, has vs contains, materialize), string-matching speed table, KQL graph operators (`make-graph`/`graph-match`/`graph()` snapshots, openCypher — in-engine KQL graph, NOT the GraphModel item; see fabric-graph), and Fabric gotchas (`;impersonate`, MV stuck at 0%, dynamic vs string, == case-sensitive).
Use when configuring Microsoft Fabric Data Agents (GA March 2026) — conversational Q&A built on Azure OpenAI Assistant APIs over Lakehouse / Warehouse / KQL / Semantic Model / Fabric SQL DB / Mirrored DB / Ontology / Microsoft Graph (≤5 sources per agent). Covers the four configuration layers (agent instructions, data source instructions, descriptions for routing, example queries ≤100/source), when to use vs semantic-model AI instructions, the governance precedence chain (organizational → role-based → developer → user intent), best practices (right-layer scoping, iterate on real questions, version control), and key limitations (read-only, structured data only, English only, 25-row/25-column response cap, no example queries on semantic model sources). The Creator Agent ('Build agent with AI', SQL/Eventhouse only), M365 Copilot Agent Store + Copilot-in-Power-BI, Python SDK, Copilot Studio, Azure AI Foundry / Agent Service, and service-principal auth (not Foundry/Copilot or KQL) all remain in preview.
Use for monitoring Fabric Warehouse queries — OPTION (LABEL = '...') for tracking, the queryinsights schema (exec_requests_history, exec_sessions_history, long_running_queries, frequently_run_queries), 30-day retention, 15-minute appearance lag, the `Invalid object name` gotcha on newly-created warehouses, and diagnosing slow/stale Lakehouse SQLEP reads under the new metadata-sync preview (`sys.dm_db_external_tables_log_status`, `sp_dw_refresh_ext_table`).
Use for scripting an open Power BI Desktop model via its localhost msmdsrv.exe Analysis Services proxy — TOM (Microsoft.AnalysisServices.Tabular) for metadata, ADOMD.NET (AdomdConnection) for DAX. Covers PowerShell setup with retail.amd64 AMO/TOM + ADOMD NuGet DLLs, discovering the msmdsrv port (msmdsrv.port.txt / netstat), connecting via server Databases Model, SaveChanges / UndoLocalChanges, ExecuteReader for EVALUATE, DAX validation pre-save, TMSL refresh types (full / calculate / automatic / dataOnly / clearValues / defragment), VertiPaq DMVs ($SYSTEM.DISCOVER_STORAGE_TABLE_COLUMN_SEGMENTS, TMSCHEMA_*), query listener via DISCOVER_SESSIONS, EVALUATEANDLOG trace events (DAXEvaluationLog), FE-vs-SE Server Timings profiling, DAXLib UDF packages (CL 1702+), Calendar Column Groups (CL 1604+). Invoke when user mentions TOM, ADOMD, msmdsrv, VertiPaq, DMV, EVALUATEANDLOG, Server Timings, daxlib.
Use for T-SQL against Fabric Warehouse (NOT Fabric SQL Database — see fabric-database). Covers unsupported types (nvarchar/datetime/money/xml/tinyint/hierarchyid), unsupported features (FOR XML, recursive CTEs, triggers, CREATE USER, cursors), MERGE (GA Jan 2026), ALTER COLUMN (preview), schema evolution (ADD nullable / DROP COLUMN / sp_rename April 2025+, IDENTITY preview, transactional ALTER TABLE GA April 2026, CTAS workaround for type changes), PK/UNIQUE/FK NONCLUSTERED+NOT ENFORCED only, 8060-byte row limit, CTAS Synapse-vs-Fabric rules (no DISTRIBUTION/CCI/explicit columns/variables), COPY INTO with AUTO_CREATE_TABLE (PARQUET/CSV/JSONL) + bcp (preview), OPENROWSET surface, snapshot-only isolation (24556/24706 retry pattern), DDL inside transactions (Sch-M lock blocks reads), Time Travel (UTC, single per SELECT; SQLEP preview) + Warehouse Snapshots (GA, REST/portal not T-SQL), sp_get_table_health_metrics (SQLEP), source control/CI-CD (preview), pipeline calls via Script activity (NOT Stored Procedure).
Use for Microsoft Fabric Graph (the GraphModel item, GA June 2026) — a labeled property graph modeled over OneLake Delta tables and queried with GQL (ISO/IEC 39075), distinct from openCypher/Cypher and from the KQL graph operators in Eventhouse. Covers the GraphModel REST path and GQL Query API (`POST /v1/workspaces/{ws}/GraphModels/{id}/executeQuery?preview=true` — app errors return HTTP 200 with GQL status codes), GQL query syntax and graph-type DDL (`(:Label => {prop :: TYPE NOT NULL})`, `CONSTRAINT ... REQUIRE (n.id) IS KEY`, `=>` inheritance, `ABSTRACT`, `+=`, `<:` refs), the item-definition JSON (dataSources / graphDefinition nodeTables+edgeTables / graphType / stylingConfiguration), save-triggers-ingest refresh, and gotchas (GQL is read-only — no DML, load via data management; no schema evolution — reingest; edges have exactly one label; no DROP GRAPH in GQL; NL2GQL still preview). Use whenever a user mentions Fabric graph models, GQL, property graphs over OneLake, or GraphModel items.