t8y2/dbx · warning · UnsupportedOperationException

Completion assistant search is not supported by this agent

Error message

Completion assistant search is not supported by this agent

What it means

completionAssistantSearch provides SQL-completion assistant lookups; the base agent defaults to throwing UnsupportedOperationException because this capability is not implemented generically. Only agents/databases with dedicated completion support override it.

Source

Thrown at agents/common/src/main/java/com/dbx/agent/BaseDatabaseAgent.java:25

public abstract class BaseDatabaseAgent implements DatabaseAgent {
    @Override
    public List<ObjectInfo> listObjects(String schema) {
        List<ObjectInfo> result = new ArrayList<>();
        for (TableInfo table : listTables(schema)) {
            result.add(new ObjectInfo(table.getName(), table.getTable_type(), schema, table.getComment()));
        }
        return result;
    }

    @Override
    public ObjectSource getObjectSource(String schema, String name, String objectType) {
        throw new UnsupportedOperationException("Object source is not supported");
    }

    @Override
    public CompletionAssistantResponse completionAssistantSearch(CompletionAssistantRequest request) {
        throw new UnsupportedOperationException("Completion assistant search is not supported by this agent");
    }

    @Override
    public String getTableDdl(String schema, String table) {
        List<IndexInfo> indexes;
        try {
            indexes = listIndexes(schema, table);
        } catch (RuntimeException e) {
            indexes = Collections.emptyList();
        }

        List<ForeignKeyInfo> foreignKeys;
        try {
            foreignKeys = listForeignKeys(schema, table);
        } catch (RuntimeException e) {
            foreignKeys = Collections.emptyList();
        }

View on GitHub (pinned to c0390bff16)

Solutions

Route completion requests to an agent implementation that supports them
Feature-detect support before calling and disable completion UI gracefully
Override completionAssistantSearch in your agent if your backend can serve it
Catch UnsupportedOperationException and return an empty result

Example fix

// before
var resp = agent.completionAssistantSearch(request); // throws
// after
CompletionAssistantResponse resp;
try {
    resp = agent.completionAssistantSearch(request);
} catch (UnsupportedOperationException e) {
    resp = CompletionAssistantResponse.empty();
}

Defensive patterns

Strategy: try-catch

Try / catch

try {
    CompletionAssistantResponse r = agent.completionAssistantSearch(request);
} catch (UnsupportedOperationException e) {
    CompletionAssistantResponse r = CompletionAssistantResponse.empty();
}

Prevention

Gate completion features per-database in configuration
Catch UnsupportedOperationException and degrade to no-completion UX
Use agents that implement completionAssistantSearch for IDE-style features
Document which drivers support the completion assistant

When it happens

Trigger: Invoking completionAssistantSearch(request) on an agent subclass that inherits the BaseDatabaseAgent default (no completion-assistant support).

Common situations: Editor/IDE completion features wired against a driver agent that lacks completion backing; uniform feature dispatch across heterogeneous database agents.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of t8y2/dbx@c0390bff16 (2026-09-05). Data as JSON: /api/errors/a4de672cc65b0f69. Report an issue: GitHub.