How do I fix azuremcp kusto_query failing on @azure/mcp 3.0.0-beta.14?

Question

Why does every azuremcp kusto_query call fail on @azure/mcp 3.0.0-beta.14 with "Cannot dynamically create an instance of type 'Azure.Mcp.Tools.Kusto.Options.QueryOptions'"? It worked on 2.0.2, and I need a workaround for the azuremcp stdio server running via npx.

Originally asked on GitHub: https://github.com/microsoft/mcp/issues/2769

AgentArmor team · Accepted Answer

Fixed: this was resolved in **@azure/mcp 3.0.0-beta.15**; a maintainer confirmed the fix and closed the issue as completed. The regression came from PR #2681, which moved the Kusto tools onto a new options pattern. A commenter traced the crash to `OptionBinder.CreateInstance` calling `Activator.CreateInstance` on the `QueryOptions` POCO, whose C# `required` members make the binder throw before any Kusto request is sent.

Until you can use beta.15, pin to 2.0.2 in your MCP config instead of `@latest`:

```json
"azuremcp": {
  "type": "stdio",
  "command": "npx",
  "tools": ["*"],
  "args": ["-y", "@azure/mcp@2.0.2", "server", "start", "--mode", "all", "--namespace", "kusto", "--namespace", "compute", "--namespace", "aks", "--namespace", "acr", "--namespace", "extension", "--namespace", "role", "--namespace", "subscription", "--namespace", "group", "--namespace", "virtualdesktop", "--namespace", "storage"]
}
```

If you cannot downgrade, a commenter bypassed the MCP tool entirely with a bash wrapper that calls the Kusto REST API against the same auth context: get a token with `az account get-access-token --resource "$CLUSTER"`, `curl` the JSON payload `{db, csl}` to `$CLUSTER/v1/rest/query`, and reformat `Tables[0]` with `jq`. They confirmed it works. Another team reverted to `beta.12` and the failure disappeared, though their client kept re-downloading `@latest`, so pin the exact version if you go that route. General advice: the token from `az account get-access-token` is a live Azure AD credential, so avoid printing it to logs or storing it in files.

AgentArmor team · Answer

**What a GitHub user tried on GitHub** (Worked)

Reporter changed the npx arg from `@azure/mcp@latest` to `@azure/mcp@2.0.2` in the stdio MCP server config; `kusto_query` then returned the expected 20 rows.

Source: https://github.com/microsoft/mcp/issues/2769

AgentArmor team · Answer

**What @Morabbin tried on GitHub** (Worked)

A commenter who could not downgrade wrote a bash wrapper that calls the Kusto REST API directly using `az account get-access-token` plus `curl` to `v1/rest/query`, converting the table rows with `jq`; they reported it works fine against the same auth context.

Source: https://github.com/microsoft/mcp/issues/2769#issuecomment-4572926601

AgentArmor team · Answer

**What @cchui-msft tried on GitHub** (Worked)

Reverting to `@azure/mcp@beta.12` fixed the failure for another team; their separate complaint was that their GHCP CLI kept re-downloading `@latest`, not that the fix itself was incomplete.

Source: https://github.com/microsoft/mcp/issues/2769#issuecomment-4583534391

AgentArmor team · Answer

**What @g2vinay tried on GitHub** (Worked)

A contributor stated the issue was resolved in the beta.15 release, and the issue was later closed as completed.

Source: https://github.com/microsoft/mcp/issues/2769#issuecomment-4585866348

How do I fix azuremcp kusto_query failing on @azure/mcp 3.0.0-beta.14?

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