dotnet/efcore · error · InvalidOperationException

A full-text index is defined for `{entityType}.{property}`,

Error message

A full-text index is defined for `{entityType}.{property}`, but full-text search was not enabled for this property. Use '{enableFullText}' method in 'OnModelCreating' to enable full-text search for this property.

What it means

Thrown by CosmosModelValidator.ValidateFullTextIndex when the single property of a full-text index does not have IsFullTextSearchEnabled set to true. The validator checks index.Properties[0].GetIsFullTextSearchEnabled() != true and names the EnableFullTextSearch extension method as the remediation. The full-text index policy and the per-property full-text flag are separate facets and both must be set consistently.

Source

Thrown at src/EFCore.Cosmos/Infrastructure/Internal/CosmosModelValidator.cs:652

    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    protected virtual void ValidateFullTextIndex(
        IIndex index,
        IDiagnosticsLogger<DbLoggerCategory.Model.Validation> logger)
    {
        if (index.Properties.Count > 1)
        {
            throw new InvalidOperationException(
                CosmosStrings.CompositeFullTextIndex(
                    index.DeclaringEntityType.DisplayName(),
                    string.Join(",", index.Properties.Select(e => e.Name))));
        }

        if (index.Properties[0] is not IProperty firstFullTextProperty
            || firstFullTextProperty.GetIsFullTextSearchEnabled() != true)
        {
            throw new InvalidOperationException(
                CosmosStrings.FullTextIndexOnNonFullTextProperty(
                    index.DeclaringEntityType.DisplayName(),
                    index.Properties[0].Name,
                    nameof(CosmosPropertyBuilderExtensions.EnableFullTextSearch)));
        }
    }

    /// <summary>
    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    protected override void ValidateProperty(
        IProperty property,
        ITypeBase structuralType,
        IDiagnosticsLogger<DbLoggerCategory.Model.Validation> logger)
    {

View on GitHub (pinned to dbf9771522)

Solutions

1. Call EnableFullTextSearch on the exact same property that the index targets, inside OnModelCreating.
2. Verify the property name in HasIndex matches the property on which EnableFullTextSearch is called.

Example fix

// before
modelBuilder.Entity<Doc>()
    .HasIndex(d => d.Summary)
    .HasFullTextIndex();

// after
modelBuilder.Entity<Doc>()
    .Property(d => d.Summary)
    .EnableFullTextSearch();
modelBuilder.Entity<Doc>()
    .HasIndex(d => d.Summary)
    .HasFullTextIndex();

// Assert the full-text flag is set on the indexed property before validation runs
foreach (var index in modelBuilder.Model.GetEntityTypes().SelectMany(e => e.GetIndexes()))
{
    if (index.Properties.Count == 1 && index.Properties[0].GetIsFullTextSearchEnabled() != true)
    {
        // decide: enable it, or remove the full-text designation
    }
}

When it happens

Trigger: Configuring builder.HasIndex(x => x.Summary).HasFullTextIndex() without first calling EnableFullTextSearch on the Summary property in the same OnModelCreating.

Common situations: Copy-pasting only the HasFullTextIndex half of the recipe, or enabling full-text on the index but on a different property than the one in the index. Generated/migrated models where the property-level facet was dropped.

Related errors

• A full-text index on '{entityType}' is defined over multiple
• The property '{propertyType} {structuralType}.{property}' ha
• The entity type '{entityType}' has property '{property}' con
• The type of the etag property '{property}' on '{entityType}'
• Trigger '{trigger}' is defined on entity type '{entityType}'

AI-assisted analysis of dotnet/efcore@dbf9771522 (2026-08-06). Data as JSON: /api/errors/52b86c338d9e19c2. Report an issue: GitHub.