diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index e4354129..88214c5f 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -540,7 +540,7 @@ en:
           provider_quantizations: "Order of provider quantizations (comma delimited list eg: fp16,fp8)"
           disable_streaming: "Disable streaming completions (convert streaming to non streaming requests)"
           reasoning_effort: "Reasoning effort (only applicable to reasoning models)"
-          enable_reasoning: "Enable reasoning (only applicable to Sonnet 3.7)"
+          enable_reasoning: "Enable reasoning (only applicable to reasoning models)"
           enable_thinking: "Enable thinking (only on applicable models eg: flash 2.5)"
           thinking_tokens: "Number of tokens used for thinking"
           reasoning_tokens: "Number of tokens used for reasoning"
diff --git a/lib/personas/tools/researcher.rb b/lib/personas/tools/researcher.rb
index 0c0921e6..d8221a5e 100644
--- a/lib/personas/tools/researcher.rb
+++ b/lib/personas/tools/researcher.rb
@@ -85,6 +85,16 @@ module DiscourseAi
               limit: max_results,
               guardian: guardian,
             )
+
+          if filter.invalid_filters.present?
+            return(
+              {
+                error:
+                  "Invalid filter fragment: #{filter.invalid_filters.join(" ")}\n\n#{self.class.filter_description}",
+              }
+            )
+          end
+
           @result_count = filter.search.count
 
           blk.call details
diff --git a/lib/utils/research/filter.rb b/lib/utils/research/filter.rb
index 630ba7f3..fe0e8033 100644
--- a/lib/utils/research/filter.rb
+++ b/lib/utils/research/filter.rb
@@ -17,7 +17,7 @@ module DiscourseAi
           ::Search.word_to_date(str)
         end
 
-        attr_reader :term, :filters, :order, :guardian, :limit, :offset
+        attr_reader :term, :filters, :order, :guardian, :limit, :offset, :invalid_filters
 
         # Define all filters at class level
         register_filter(/\Astatus:open\z/i) do |relation, _, _|
@@ -206,7 +206,6 @@ module DiscourseAi
         end
 
         def initialize(term, guardian: nil, limit: nil, offset: nil)
-          @term = term.to_s
           @guardian = guardian || Guardian.new
           @limit = limit
           @offset = offset
@@ -214,8 +213,10 @@ module DiscourseAi
           @valid = true
           @order = :latest_post
           @topic_ids = nil
+          @invalid_filters = []
+          @term = term.to_s.strip
 
-          @term = process_filters(@term)
+          process_filters(@term)
         end
 
         def set_order!(order)
@@ -248,12 +249,16 @@ module DiscourseAi
           end
 
           if @topic_ids.present?
-            filtered =
-              original_filtered.where(
-                "posts.topic_id IN (?) OR posts.id IN (?)",
-                @topic_ids,
-                filtered.select("posts.id"),
-              )
+            if original_filtered == filtered
+              filtered = original_filtered.where("posts.topic_id IN (?)", @topic_ids)
+            else
+              filtered =
+                original_filtered.where(
+                  "posts.topic_id IN (?) OR posts.id IN (?)",
+                  @topic_ids,
+                  filtered.select("posts.id"),
+                )
+            end
           end
 
           filtered = filtered.limit(@limit) if @limit.to_i > 0
@@ -275,7 +280,7 @@ module DiscourseAi
         private
 
         def process_filters(term)
-          return "" if term.blank?
+          return if term.blank?
 
           term
             .to_s
@@ -293,10 +298,8 @@ module DiscourseAi
                 end
               end
 
-              found ? nil : word
+              invalid_filters << word if !found
             end
-            .compact
-            .join(" ")
         end
       end
     end
diff --git a/spec/lib/personas/tools/researcher_spec.rb b/spec/lib/personas/tools/researcher_spec.rb
index b3784cac..23ed98a7 100644
--- a/spec/lib/personas/tools/researcher_spec.rb
+++ b/spec/lib/personas/tools/researcher_spec.rb
@@ -17,10 +17,23 @@ RSpec.describe DiscourseAi::Personas::Tools::Researcher do
 
   fab!(:topic_with_tags) { Fabricate(:topic, category: category, tags: [tag_research, tag_data]) }
   fab!(:post) { Fabricate(:post, topic: topic_with_tags) }
+  fab!(:another_post) { Fabricate(:post) }
 
   before { SiteSetting.ai_bot_enabled = true }
 
   describe "#invoke" do
+    it "can correctly filter to a topic id" do
+      researcher =
+        described_class.new(
+          { dry_run: true, filter: "topic:#{topic_with_tags.id}", goals: "analyze topic content" },
+          bot_user: bot_user,
+          llm: llm,
+          context: DiscourseAi::Personas::BotContext.new(user: user, post: post),
+        )
+      results = researcher.invoke(&progress_blk)
+      expect(results[:number_of_posts]).to eq(1)
+    end
+
     it "returns filter information and result count" do
       researcher =
         described_class.new(
@@ -63,6 +76,20 @@ RSpec.describe DiscourseAi::Personas::Tools::Researcher do
       expect(researcher.options[:max_results]).to eq(50)
     end
 
+    it "returns error for invalid filter fragments" do
+      researcher =
+        described_class.new(
+          { filter: "invalidfilter tag:research", goals: "analyze content" },
+          bot_user: bot_user,
+          llm: llm,
+          context: DiscourseAi::Personas::BotContext.new(user: user, post: post),
+        )
+
+      results = researcher.invoke(&progress_blk)
+
+      expect(results[:error]).to include("Invalid filter fragment")
+    end
+
     it "returns correct results for non-dry-run with filtered posts" do
       # Stage 2 topics, each with 2 posts
       topics = Array.new(2) { Fabricate(:topic, category: category, tags: [tag_research]) }