diff --git a/db/migrate/20250125162658_fix_broken_open_ai_embeddings_config.rb b/db/migrate/20250125162658_fix_broken_open_ai_embeddings_config.rb
new file mode 100644
index 000000000..32b6ab80e
--- /dev/null
+++ b/db/migrate/20250125162658_fix_broken_open_ai_embeddings_config.rb
@@ -0,0 +1,107 @@
+# frozen_string_literal: true
+
+class FixBrokenOpenAiEmbeddingsConfig < ActiveRecord::Migration[7.2]
+  def up
+    return if fetch_setting("ai_embeddings_selected_model").present?
+
+    return if DB.query_single("SELECT COUNT(*) FROM embedding_definitions").first > 0
+
+    open_ai_models = %w[text-embedding-3-large text-embedding-3-small text-embedding-ada-002]
+    current_model = fetch_setting("ai_embeddings_model")
+    return if !open_ai_models.include?(current_model)
+
+    endpoint = fetch_setting("ai_openai_embeddings_url") || "https://api.openai.com/v1/embeddings"
+    api_key = fetch_setting("ai_openai_api_key")
+    return if api_key.blank?
+
+    attrs = {
+      display_name: current_model,
+      url: endpoint,
+      api_key: api_key,
+      provider: "open_ai",
+    }.merge(model_attrs(current_model))
+
+    persist_config(attrs)
+  end
+
+  def fetch_setting(name)
+    DB.query_single(
+      "SELECT value FROM site_settings WHERE name = :setting_name",
+      setting_name: name,
+    ).first || ENV["DISCOURSE_#{name&.upcase}"]
+  end
+
+  def model_attrs(model_name)
+    if model_name == "text-embedding-3-large"
+      {
+        dimensions: 2000,
+        max_sequence_length: 8191,
+        id: 7,
+        pg_function: "<=>",
+        tokenizer_class: "DiscourseAi::Tokenizer::OpenAiTokenizer",
+        matryoshka_dimensions: true,
+        provider_params: {
+          model_name: "text-embedding-3-large",
+        },
+      }
+    elsif model_name == "text-embedding-3-small"
+      {
+        dimensions: 1536,
+        max_sequence_length: 8191,
+        id: 6,
+        pg_function: "<=>",
+        tokenizer_class: "DiscourseAi::Tokenizer::OpenAiTokenizer",
+        provider_params: {
+          model_name: "text-embedding-3-small",
+        },
+      }
+    else
+      {
+        dimensions: 1536,
+        max_sequence_length: 8191,
+        id: 2,
+        pg_function: "<=>",
+        tokenizer_class: "DiscourseAi::Tokenizer::OpenAiTokenizer",
+        provider_params: {
+          model_name: "text-embedding-ada-002",
+        },
+      }
+    end
+  end
+
+  def persist_config(attrs)
+    DB.exec(
+      <<~SQL,
+      INSERT INTO embedding_definitions (id, display_name, dimensions, max_sequence_length, version, pg_function, provider, tokenizer_class, url, api_key, provider_params, matryoshka_dimensions, created_at, updated_at)
+      VALUES (:id, :display_name, :dimensions, :max_sequence_length, 1, :pg_function, :provider, :tokenizer_class, :url, :api_key, :provider_params, :matryoshka_dimensions, :now, :now)
+      SQL
+      id: attrs[:id],
+      display_name: attrs[:display_name],
+      dimensions: attrs[:dimensions],
+      max_sequence_length: attrs[:max_sequence_length],
+      pg_function: attrs[:pg_function],
+      provider: attrs[:provider],
+      tokenizer_class: attrs[:tokenizer_class],
+      url: attrs[:url],
+      api_key: attrs[:api_key],
+      provider_params: attrs[:provider_params]&.to_json,
+      matryoshka_dimensions: !!attrs[:matryoshka_dimensions],
+      now: Time.zone.now,
+    )
+
+    # We hardcoded the ID to match with already generated embeddings. Let's restart the seq to avoid conflicts.
+    DB.exec(
+      "ALTER SEQUENCE embedding_definitions_id_seq RESTART WITH :new_seq",
+      new_seq: attrs[:id].to_i + 1,
+    )
+
+    DB.exec(<<~SQL, new_value: attrs[:id])
+      INSERT INTO site_settings(name, data_type, value, created_at, updated_at)
+      VALUES ('ai_embeddings_selected_model', 3, ':new_value', NOW(), NOW())
+    SQL
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end
diff --git a/db/migrate/20250127145305_clean_unused_embedding_search_indexes.rb b/db/migrate/20250127145305_clean_unused_embedding_search_indexes.rb
new file mode 100644
index 000000000..9c6e0d177
--- /dev/null
+++ b/db/migrate/20250127145305_clean_unused_embedding_search_indexes.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+class CleanUnusedEmbeddingSearchIndexes < ActiveRecord::Migration[7.2]
+  def up
+    existing_definitions =
+      DB.query("SELECT id, dimensions FROM embedding_definitions WHERE id <= 8")
+
+    drop_statements =
+      (1..8)
+        .reduce([]) do |memo, model_id|
+          model = existing_definitions.find { |ed| ed&.id == model_id }
+
+          if model.blank? || !correctly_indexed?(model)
+            embedding_tables.each do |type|
+              memo << "DROP INDEX IF EXISTS ai_#{type}_embeddings_#{model_id}_1_search_bit;"
+            end
+          end
+
+          memo
+        end
+        .join("\n")
+
+    DB.exec(drop_statements) if drop_statements.present?
+
+    amend_statements =
+      (1..8)
+        .reduce([]) do |memo, model_id|
+          model = existing_definitions.find { |ed| ed&.id == model_id }
+
+          memo << amended_idxs(model) if model.present? && !correctly_indexed?(model)
+
+          memo
+        end
+        .join("\n")
+
+    DB.exec(amend_statements) if amend_statements.present?
+  end
+
+  def embedding_tables
+    %w[topics posts document_fragments]
+  end
+
+  def amended_idxs(model)
+    embedding_tables.map { |t| <<~SQL }.join("\n")
+      CREATE INDEX IF NOT EXISTS ai_#{t}_embeddings_#{model.id}_1_search_bit ON ai_#{t}_embeddings
+      USING hnsw ((binary_quantize(embeddings)::bit(#{model.dimensions})) bit_hamming_ops)
+      WHERE model_id = #{model.id} AND strategy_id = 1;
+    SQL
+  end
+
+  def correctly_indexed?(edef)
+    seeded_dimensions[edef.id] == edef.dimensions
+  end
+
+  def seeded_dimensions
+    { 1 => 768, 2 => 1536, 3 => 1024, 4 => 1024, 5 => 768, 6 => 1536, 7 => 2000, 8 => 1024 }
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end
diff --git a/spec/db/migrate/20250125162658_fix_broken_open_ai_embeddings_config_spec.rb b/spec/db/migrate/20250125162658_fix_broken_open_ai_embeddings_config_spec.rb
new file mode 100644
index 000000000..1c621a7be
--- /dev/null
+++ b/spec/db/migrate/20250125162658_fix_broken_open_ai_embeddings_config_spec.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require Rails.root.join(
+          "plugins/discourse-ai/db/migrate/20250125162658_fix_broken_open_ai_embeddings_config",
+        )
+
+RSpec.describe FixBrokenOpenAiEmbeddingsConfig do
+  let(:connection) { ActiveRecord::Base.connection }
+
+  def store_setting(name, val)
+    connection.execute <<~SQL
+      INSERT INTO site_settings(name, data_type, value, created_at, updated_at)
+      VALUES ('#{name}', 3, '#{val}', NOW(), NOW())
+    SQL
+  end
+
+  def configured_model_id
+    DB.query_single(
+      "SELECT value FROM site_settings WHERE name = 'ai_embeddings_selected_model'",
+    ).first
+  end
+
+  describe "#up" do
+    context "when embeddings are already configured" do
+      fab!(:embedding_definition)
+
+      before { store_setting("ai_embeddings_selected_model", embedding_definition.id) }
+
+      it "does nothing" do
+        subject.up
+
+        expect(configured_model_id).to eq(embedding_definition.id.to_s)
+      end
+    end
+
+    context "when there is no previous config" do
+      it "does nothing" do
+        subject.up
+
+        expect(configured_model_id).to be_blank
+      end
+    end
+
+    context "when things are not fully configured" do
+      before do
+        store_setting("ai_embeddings_model", "text-embedding-3-large")
+        store_setting("ai_openai_api_key", "")
+      end
+
+      it "does nothing" do
+        subject.up
+
+        expect(configured_model_id).to be_blank
+      end
+    end
+
+    context "when we have a configuration that previously failed to copy" do
+      before do
+        store_setting("ai_embeddings_model", "text-embedding-3-large")
+        store_setting("ai_openai_api_key", "123")
+      end
+
+      it "copies the config" do
+        subject.up
+
+        embedding_def = EmbeddingDefinition.last
+
+        expect(configured_model_id).to eq(embedding_def.id.to_s)
+      end
+    end
+  end
+end
diff --git a/spec/db/migrate/20250127145305_clean_unused_embedding_search_indexes_spec.rb b/spec/db/migrate/20250127145305_clean_unused_embedding_search_indexes_spec.rb
new file mode 100644
index 000000000..2278692f9
--- /dev/null
+++ b/spec/db/migrate/20250127145305_clean_unused_embedding_search_indexes_spec.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require Rails.root.join(
+          "plugins/discourse-ai/db/migrate/20250127145305_clean_unused_embedding_search_indexes",
+        )
+
+RSpec.describe CleanUnusedEmbeddingSearchIndexes do
+  let(:connection) { ActiveRecord::Base.connection }
+
+  describe "#up" do
+    before do
+      # Copied from 20241008054440_create_binary_indexes_for_embeddings
+      %w[topics posts document_fragments].each do |type|
+        # our supported embeddings models IDs and dimensions
+        [
+          [1, 768],
+          [2, 1536],
+          [3, 1024],
+          [4, 1024],
+          [5, 768],
+          [6, 1536],
+          [7, 2000],
+          [8, 1024],
+        ].each { |model_id, dimensions| connection.execute <<-SQL }
+          CREATE INDEX IF NOT EXISTS ai_#{type}_embeddings_#{model_id}_1_search_bit ON ai_#{type}_embeddings
+          USING hnsw ((binary_quantize(embeddings)::bit(#{dimensions})) bit_hamming_ops)
+          WHERE model_id = #{model_id} AND strategy_id = 1;
+        SQL
+      end
+    end
+
+    let(:all_idx_names) do
+      %w[topics posts document_fragments].reduce([]) do |memo, type|
+        (1..8).each { |model_id| memo << "ai_#{type}_embeddings_#{model_id}_1_search_bit" }
+
+        memo
+      end
+    end
+
+    context "when there are no embedding definitions" do
+      it "removes all indexes" do
+        subject.up
+
+        remaininig_idxs =
+          DB.query_single(
+            "SELECT indexname FROM pg_indexes WHERE indexname IN (:names)",
+            names: all_idx_names,
+          )
+
+        expect(remaininig_idxs).to be_empty
+      end
+    end
+
+    context "when there is an embedding definition with the same dimensions" do
+      fab!(:embedding_def) { Fabricate(:embedding_definition, id: 2, dimensions: 1536) }
+
+      it "keeps the matching index and removes the rest" do
+        expected_model_idxs =
+          %w[topics posts document_fragments].reduce([]) do |memo, type|
+            memo << "ai_#{type}_embeddings_2_1_search_bit"
+          end
+
+        subject.up
+
+        remaininig_idxs =
+          DB.query_single(
+            "SELECT indexname FROM pg_indexes WHERE indexname IN (:names)",
+            names: all_idx_names,
+          )
+
+        expect(remaininig_idxs).to contain_exactly(*expected_model_idxs)
+        # This method checks dimensions are correct.
+        expect(DiscourseAi::Embeddings::Schema.correctly_indexed?(embedding_def)).to eq(true)
+      end
+    end
+
+    context "when there is an embedding definition with different dimenstions" do
+      fab!(:embedding_def) { Fabricate(:embedding_definition, id: 2, dimensions: 1536) }
+      fab!(:embedding_def_2) { Fabricate(:embedding_definition, id: 3, dimensions: 768) }
+
+      it "updates the index to use the right dimensions" do
+        expected_model_idxs =
+          %w[topics posts document_fragments].reduce([]) do |memo, type|
+            memo << "ai_#{type}_embeddings_2_1_search_bit"
+            memo << "ai_#{type}_embeddings_3_1_search_bit"
+          end
+
+        subject.up
+
+        remaininig_idxs =
+          DB.query_single(
+            "SELECT indexname FROM pg_indexes WHERE indexname IN (:names)",
+            names: all_idx_names,
+          )
+
+        expect(remaininig_idxs).to contain_exactly(*expected_model_idxs)
+        # This method checks dimensions are correct.
+        expect(DiscourseAi::Embeddings::Schema.correctly_indexed?(embedding_def_2)).to eq(true)
+      end
+    end
+
+    context "when there are indexes outside the pre-seeded range" do
+      before { %w[topics posts document_fragments].each { |type| connection.execute <<-SQL } }
+            CREATE INDEX IF NOT EXISTS ai_#{type}_embeddings_9_1_search_bit ON ai_#{type}_embeddings
+            USING hnsw ((binary_quantize(embeddings)::bit(556)) bit_hamming_ops)
+            WHERE model_id = 9 AND strategy_id = 1;
+          SQL
+
+      let(:all_idx_names) do
+        %w[topics posts document_fragments].reduce([]) do |memo, type|
+          (1..8).each { |model_id| memo << "ai_#{type}_embeddings_#{model_id}_1_search_bit" }
+
+          memo
+        end
+      end
+
+      it "leaves them untouched" do
+        expected_model_idxs =
+          %w[topics posts document_fragments].reduce([]) do |memo, type|
+            memo << "ai_#{type}_embeddings_9_1_search_bit"
+          end
+
+        subject.up
+
+        other_idxs =
+          DB.query_single(
+            "SELECT indexname FROM pg_indexes WHERE indexname IN (:names)",
+            names: expected_model_idxs,
+          )
+
+        expect(other_idxs).to contain_exactly(*expected_model_idxs)
+      end
+    end
+  end
+end