Troubleshooting & FAQ
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Login and license
Nothing works — completion, hover, and commands seem inert.
Most features are gated behind a valid login and license. Run neonto: Login / Authenticate from the Command Palette, and neonto: Activate License if you haven't activated one yet. If the problem persists, contact support@neonto.de.
I was logged in, but now I'm not.
Re-run neonto: Login / Authenticate. If you need to switch accounts, run neonto: Logout first.
Large files
Completion or hover doesn't work on a large .ttl/.trig file.
The file may exceed neonto.langServer.maxFileSize (default 256 MB), so its terms are not available for completion, hover, or workspace-wide term resolution. Raise the limit in Settings if you have the memory budget for it.
Diagnostics don't update as I type in a large file.
Live diagnostics (vocabulary checks, SHACL validation) are skipped above neonto.langServer.liveDiagnosticsMaxFileSizeKb (default 1024 KB). Either raise that setting, or validate on demand with neonto: Run SHACL Validation / neonto: Run All SHACL Validations.
SPARQL
My SPARQL query times out before it finishes.
Raise neonto.langServer.sparqlQueryTimeout (default 5000 ms, max 20000 ms) in Settings.
A SPARQL endpoint shows as unreachable or queries against it fail.
Check the endpoint URL and credentials in the Data Source Connections view. See Endpoint Credentials for how credentials are stored and neonto.langServer.sparqlStoreCredentials for whether they persist locally. Also confirm the endpoint is reachable from your network and that CORS/auth settings on the server side allow the request.
MCP server
Do I need to start the MCP server myself?
No. It's an in-process Streamable HTTP server that starts automatically when the extension activates, listening on http://127.0.0.1:<port>/mcp (localhost only) — there's no separate command or process to launch.
The MCP server doesn't show up for my agent.
The MCP server only runs in desktop VS Code (as part of the local/desktop extension), not in web/browser VS Code, and requires you to be logged in with a valid license. Use neonto: Set Up AI Agent to generate the MCP config and instruction files for your agent, or neonto: Copy MCP Server URL for the HTTP endpoint.
The MCP server fails to start, or an agent can't connect.
This is usually a port conflict. The server prefers neonto.mcp.port (default 6789) but falls back to a random available port if that one is taken — copy the current URL again with neonto: Copy MCP Server URL rather than assuming the configured port is in use.
An MCP file tool refuses to read or write a path.
By default, MCP file tools (sparql_query, run_yarrrml, validate_yarrrml, yarrrml_inspect_source) are confined to the open workspace folders. Enable neonto.mcp.allowExternalPaths if you genuinely need to work with files outside the workspace. See Security.
Vocabularies
Linked Open Vocabularies (LOV) lookups seem to fail or hang intermittently.
LOV lookups depend on network availability. The extension backs off and retries when LOV is unreachable; if you're offline or on a restricted network, expect degraded hover/completion for external vocabulary terms until connectivity is restored.
Diagnosing performance issues
Enable neonto.perfLogging to capture detailed performance timings in the neonto Perf output channel (View → Output, then select "neonto Perf" from the channel dropdown). Useful when reporting a performance issue to support.