diff --git a/lib/agents/researcher.tsx b/lib/agents/researcher.tsx
index 2004485f..87c032f6 100644
--- a/lib/agents/researcher.tsx
+++ b/lib/agents/researcher.tsx
@@ -6,11 +6,12 @@ import {
   ToolCallPart,
   ToolResultPart,
   streamText as nonexperimental_streamText,
+  generateText,
 } from 'ai'
 import { Section } from '@/components/section'
 import { BotMessage } from '@/components/message'
 import { getTools } from './tools'
-import { getModel } from '../utils'
+import { getModel, getReasoningProviderOptions, isNonStreamingModel } from '../utils'
 import { MapProvider } from '@/lib/store/settings'
 import { DrawnFeature } from './resolution-search'
 import { getSelectedModel } from '@/lib/actions/users'
@@ -157,10 +158,37 @@ export async function researcher(
       : 'none'
   })
 
-  const result = await nonexperimental_streamText({
-    model: (await getModel(hasImage)) as LanguageModel,
-    maxTokens: 2500,
+  const model = await getModel(hasImage)
+  const generationOptions = {
+    model: model as LanguageModel,
+    maxTokens: 4096,
     temperature: 0,
+    providerOptions: getReasoningProviderOptions(model),
+    maxSteps: 5,
+    abortSignal: createDeadlineSignal(AI_REQUEST_TIMEOUT_MS),
+    system: systemPromptToUse,
+    messages,
+    tools: getTools({ uiStream, fullResponse, mapProvider, selectedModel, drawnFeatures }),
+  }
+
+  if (isNonStreamingModel(model)) {
+    const generated = await generateText(generationOptions)
+    uiStream.update(null)
+    fullResponse = generated.text || ''
+    const generatedToolCalls = (generated.toolCalls || []) as ToolCallPart[]
+    const generatedToolResults = (generated.toolResults || []) as ToolResultPart[]
+    if (fullResponse.trim()) {
+      uiStream.append(answerSection)
+      streamText.update(fullResponse)
+    }
+    streamText.done(fullResponse)
+    messages.push({ role: 'assistant', content: [{ type: 'text', text: fullResponse }, ...generatedToolCalls] })
+    if (generatedToolResults.length > 0) messages.push({ role: 'tool', content: generatedToolResults })
+    return { result: generated, fullResponse, hasError: false, toolResponses: generatedToolResults }
+  }
+
+  const result = await nonexperimental_streamText({
+    ...generationOptions,
     // Allow multi-step tool calling (tool round + synthesis step with headroom for chained tool calls)
     maxSteps: 5,
     abortSignal: createDeadlineSignal(AI_REQUEST_TIMEOUT_MS),
@@ -199,13 +227,35 @@ export async function researcher(
 
       case 'error':
         hasError = true
+        console.error('Model response generation failed:', delta.error)
         fullResponse += `\n\nError: Model response generation failed.`
         break
     }
   }
 
-  if (toolResponses.length > 0 && !hasError && fullResponse.trim().length === 0) {
+  // Some reasoning-model/provider combinations finish with the final text
+  // available on result.text without emitting a text-delta event. Recover it
+  // before finalizing the stream so the response section cannot remain empty.
+  if (fullResponse.trim().length === 0) {
+    try {
+      const completedText = await result.text
+      if (completedText?.trim()) {
+        fullResponse = completedText
+      }
+    } catch (error) {
+      console.error('Unable to recover completed model text:', error)
+    }
+  }
+
+  if (fullResponse.trim().length === 0 && toolResponses.length > 0 && !hasError) {
     fullResponse = 'Information gathered from search results.'
+  }
+
+  if (fullResponse.trim().length === 0 && !hasError) {
+    fullResponse = 'The model returned no visible response. Please try again.'
+  }
+
+  if (fullResponse.trim().length > 0) {
     if (!hasAppendedAnswerSection) {
       uiStream.append(answerSection)
       hasAppendedAnswerSection = true
diff --git a/lib/agents/resolution-search.tsx b/lib/agents/resolution-search.tsx
index c99b42e0..7fd89c04 100644
--- a/lib/agents/resolution-search.tsx
+++ b/lib/agents/resolution-search.tsx
@@ -1,5 +1,5 @@
-import { CoreMessage, streamObject } from 'ai'
-import { getModel } from '@/lib/utils'
+import { CoreMessage, generateObject, streamObject } from 'ai'
+import { getModel, getReasoningProviderOptions, isNonStreamingModel } from '@/lib/utils'
 import { tavily } from '@tavily/core'
 import { resolutionSearchSchema } from '@/lib/schema/resolution-search'
 import { AI_REQUEST_TIMEOUT_MS, ENRICHMENT_TIMEOUT_MS, createDeadlineSignal, withTimeout } from '@/lib/utils/with-timeout'
@@ -187,14 +187,32 @@ Analyze the user's prompt and the image to provide a holistic understanding of t
     message.content.some((part: any) => part.type === 'image')
   )
 
-  // Use streamObject to get partial results.
-  return withTimeout(Promise.resolve(streamObject({
-    model: await getModel(hasImage),
+  // Use streamed output when the provider supports it. The configured GPT-5.5
+  // endpoint is explicitly non-streaming, so use generateObject and expose the
+  // completed object through the same async interface consumed by actions.tsx.
+  const model = await getModel(hasImage)
+  const generationOptions = {
+    model,
     system: systemPrompt,
     messages: filteredMessages,
     schema: resolutionSearchSchema,
     temperature: 0,
-    maxTokens: 1800,
+    maxTokens: 4096,
+    providerOptions: getReasoningProviderOptions(model),
     abortSignal: createDeadlineSignal(AI_REQUEST_TIMEOUT_MS),
-  })), AI_REQUEST_TIMEOUT_MS, 'Resolution analysis')
+  }
+
+  if (isNonStreamingModel(model)) {
+    const generated = await generateObject(generationOptions)
+    return {
+      partialObjectStream: (async function* () { yield generated.object })(),
+      object: Promise.resolve(generated.object),
+    }
+  }
+
+  return withTimeout(
+    Promise.resolve(streamObject(generationOptions)),
+    AI_REQUEST_TIMEOUT_MS,
+    'Resolution analysis'
+  )
 }
diff --git a/lib/utils/index.ts b/lib/utils/index.ts
index 5b4f03e1..b497c6ae 100644
--- a/lib/utils/index.ts
+++ b/lib/utils/index.ts
@@ -67,14 +67,15 @@ export async function getModel(requireVision: boolean = false) {
             console.error('User selected "Gemini 3.1 Pro" but GEMINI_3_PRO_API_KEY is not set.');
             throw new Error('Selected model is not configured.');
         }
+      case 'GPT-5.6':
       case 'GPT-5.1':
         if (openaiApiKey) {
           const openai = createOpenAI({
             apiKey: openaiApiKey,
           });
-          return openai('gpt-4o');
+          return openai.responses('gpt-5.5');
         } else {
-            console.error('User selected "GPT-5.1" but OPENAI_API_KEY is not set.');
+            console.error('User selected "GPT-5.6" but OPENAI_API_KEY is not set.');
             throw new Error('Selected model is not configured.');
         }
     }
@@ -86,7 +87,7 @@ export async function getModel(requireVision: boolean = false) {
       const openai = createOpenAI({
         apiKey: openaiApiKey,
       });
-      return openai('gpt-4o');
+      return openai.responses('gpt-5.5');
     } catch (error) {
       console.warn('OpenAI API unavailable, falling back to next provider:', error);
     }
@@ -135,7 +136,24 @@ export async function getModel(requireVision: boolean = false) {
   const openai = createOpenAI({
     apiKey: openaiApiKey,
   });
-  return openai('gpt-4o');
+  return openai.responses('gpt-5.5');
+}
+
+/**
+ * GPT-5 and o-series models share their output budget with hidden reasoning.
+ * Bound reasoning so streamed user-visible text is not starved. Detect the
+ * actual model because getModel can fall back to another provider.
+ */
+export function getReasoningProviderOptions(model: { modelId?: string }) {
+  const modelId = model?.modelId ?? ''
+  return modelId.startsWith('gpt-5') || modelId.startsWith('o')
+    ? { openai: { reasoningEffort: 'low' as const } }
+    : undefined
+}
+
+/** The configured API advertises GPT-5.5 as non-streaming. */
+export function isNonStreamingModel(model: { modelId?: string }) {
+  return model?.modelId === 'gpt-5.5'
 }
 
 /**