AI Tool Selector — CFO Organization

⚠️ Wait — what's an "add-in" and how is it different from Copilot?

This is one of the most common sources of confusion, and it's totally understandable. Here's the short answer: Copilot is built into Microsoft Office by Microsoft. The Claude and ChatGPT add-ins are separate tools installed on top of Office by Anthropic and OpenAI respectively. They appear in a sidebar inside Excel or PowerPoint, but they are running on different servers and require their own subscriptions.

One more wrinkle: there are unofficial "ChatGPT for Excel" add-ins in the Microsoft Marketplace (made by third parties, not OpenAI) that look similar to the official one. The official OpenAI add-in is simply called "ChatGPT" in the Microsoft Marketplace and requires a ChatGPT Plus, Team, or Enterprise account. If you had to enter a separate API key to set yours up, you may have the unofficial version.

All three tools are appropriate for business use — but they have different data privacy implications. See the cards below for details.

💡 Power User Strategy

Copilot is powerful, but hard to prompt.
Use Claude or ChatGPT to write your Copilot prompts.

This is a real, recognized strategy among experienced AI users — and it works. Copilot's interface is optimized for speed inside Microsoft apps, but it's less flexible at interpreting vague or complex instructions. Claude and ChatGPT are far better at understanding what you mean, even when you explain it imperfectly. So: figure out what you want to do in Copilot, go to Claude or ChatGPT first to build the perfect prompt, then copy that prompt into Copilot to get the result. Think of it as Claude being your prompt ghostwriter.

Step 1

Describe your goal

Tell Claude or ChatGPT what you're trying to do in Excel/PowerPoint in plain English — as vaguely as you want.

Claude ChatGPT

Step 2

Ask for a Copilot prompt

Ask: "Write me a Copilot prompt I can paste into Excel to achieve this."

Claude ChatGPT

Step 3

Paste into Copilot

Copy the generated prompt and paste it directly into Copilot inside Excel or PowerPoint.

Copilot

🪟

Microsoft Copilot

Built into Microsoft 365 — Word, Excel, Outlook, Teams, PowerPoint

Copilot is Microsoft's own AI, embedded directly in your Office ribbon. It's not a separate app — it appears as a pane inside the tool you're already in. Its defining advantage is that it can read your entire Microsoft ecosystem: Outlook emails, Teams chats, SharePoint files, and calendar — all without copy-pasting. Your data never leaves your Microsoft 365 tenant, which is the most enterprise-secure option of the three.

Strengths

No context-switching — works inside the app
Accesses Outlook, Teams, SharePoint automatically
Highest data security (stays inside M365 tenant)
Builds charts and pivot tables natively in Excel
Summarizes Teams meetings from transcript
Creates actual .pptx files in PowerPoint

Limitations

Hard to prompt — needs very specific instructions
Excel Agent Mode requires OneDrive (no local files)
Weaker at complex reasoning and long documents
Less useful for open-ended creative or analytical tasks
Expensive add-on (~$30/user/month on top of M365)

💰 ~$30/user/month (M365 add-on) 🔒 Data stays in M365 tenant 📁 Requires OneDrive for Agent Mode

🧡

Claude (Anthropic)

Standalone chat + official Excel & PowerPoint add-ins

Claude is available as a standalone web/app tool and as official Excel and PowerPoint add-ins (installed from Microsoft Marketplace). The add-ins open as a sidebar inside Office and are powered by Claude Opus — Anthropic's most capable model — specifically tuned for financial and spreadsheet work. A March 2026 update lets the Excel and PowerPoint add-ins share context with each other. It works with local files (unlike Copilot's Agent Mode), and asks your permission before making any changes.

Strengths

Best at nuanced writing and long documents
Works with local files (no OneDrive required)
Asks permission before editing — full control
Excellent at explaining complex formulas clearly
Best for sensitive/executive communications
"Skills" feature: save repeatable workflows

Limitations

Data sent to Anthropic (outside M365 tenant)
No access to Outlook/Teams/SharePoint context
Add-in requires separate Claude paid plan
Cannot create standalone .pptx files
No live web search by default

💰 From ~$20/month (Pro) ⚠️ Data sent to Anthropic servers 📁 Works with local Excel files

💬

ChatGPT (OpenAI)

Standalone chat + official Excel add-in (beta)

ChatGPT is available as a standalone tool and, as of early 2026, as an official Excel add-in in public beta (powered by GPT-5.4). Important: the Excel add-in does NOT connect to your main ChatGPT chat history and has no memory during beta. There are also several unofficial "ChatGPT for Excel" add-ins in the Marketplace made by third parties — if you had to enter an API key to set yours up, you likely have one of those. ChatGPT stands out for its strong web search, versatility, and the widest ecosystem of integrations.

Strengths

Best live web search of the three
Strong Deep Research mode for multi-source analysis
Most versatile — widest range of tasks
Great for creating charts from data
Most widely recognized — easiest team adoption

Limitations

Excel add-in is beta — VBA/macros not yet supported
Add-in does not sync with main ChatGPT history
Data sent to OpenAI (outside M365 tenant)
Unofficial add-ins in Marketplace cause confusion
Writing can be less nuanced than Claude

💰 From ~$20/month (Plus) ⚠️ Data sent to OpenAI servers ⚠️ Excel add-in = beta (2026)

🔄

Add-in vs. Copilot: Side-by-Side in Excel

When to use which tool directly in your spreadsheet

Situation	Copilot	Claude Add-in	ChatGPT Add-in
File saved to OneDrive	✓ Full Agent Mode	✓ Works fine	✓ Works fine
File saved locally (not OneDrive)	✗ Agent Mode limited	✓ Full capability	✓ Full capability
Data must stay in M365 tenant	✓ Best choice	✗ Goes to Anthropic	✗ Goes to OpenAI
Complex formula explanation needed	OK	✓ Best	Good
Build charts / visual output fast	✓ Best (native)	Good	Good
Cross-reference with Teams / Outlook	✓ Only option	✗ Not possible	✗ Not possible
Write VBA macros from within Excel	Limited	✓ Best	✗ Beta limitation

Tools:

Claude

ChatGPT

Copilot

BEST Top pick

GOOD Works well

LIMITED Not ideal

🔍

Data & Excel

Analyze an uploaded Excel or CSV file

Claude

BestHandles large multi-tab workbooks; excels at narrative interpretation of what the numbers mean

ChatGPT

BestCode Interpreter is excellent for statistical charts and pivot-style analysis

Copilot

GoodBest when file is in OneDrive; can cross-reference email/Teams context

💡 Tip: Upload your file directly to Claude or ChatGPT. Tell it what question you need to answer (e.g., "what are the top 3 reasons our Q3 actuals missed budget?") not just "analyze this."

🧡 Claude: Opus (Excel add-in) 🔵 Claude: Sonnet (standalone chat) 💬 ChatGPT: Instant

!! DATA GOVERNANCE: Do not upload or share confidential Rackspace data with Claude or ChatGPT. If your file contains confidential data, use Copilot — it is covered under Microsoft's EDP within our M365 environment.

Data & Excel

Build an Excel formula from plain English

Claude

BestWrites accurate formulas and explains step-by-step what each part does — ideal for learning

ChatGPT

BestVery strong; especially good at complex nested formulas

Copilot

BestFastest when you're already in Excel — no switching apps; inserts formula directly into selected cell

💡 Tip: If Copilot's formula isn't what you expected, take your request to Claude first, ask it to "write me a Copilot prompt to build this formula," then paste that into Copilot.

🔵 Claude: Sonnet 💬 ChatGPT: Instant

Data & Excel

Budget vs. actuals variance analysis

Claude

BestInterprets the "why" behind variances, not just the numbers — produces CFO-ready narrative commentary

ChatGPT

GoodStrong analysis; can also build variance charts automatically

Copilot

GoodWorks best when the file is in SharePoint/OneDrive; less nuanced narrative output

💡 Tip: Upload your CSV to Claude and say: "Identify the top 5 variance drivers vs. budget and give me 2-3 sentence commentary on each for a CFO review." You'll have your narrative in under a minute.

🧡 Claude: Opus — best for complex variance reasoning 🧠 Try Extended Thinking for multi-factor analysis

!! DATA GOVERNANCE: Do not upload or share confidential Rackspace financial data with Claude or ChatGPT. If your data is confidential, use Copilot — it is covered under Microsoft's EDP within our M365 environment.

Data & Excel

Create charts and data visualizations

Claude

GoodCan build interactive charts via its artifact feature but doesn't insert them natively into Excel

ChatGPT

BestCode Interpreter generates polished, exportable charts with custom styling from your data

Copilot

BestInserts native Excel charts directly into your sheet — fastest path if file is in OneDrive

💡 Tip: For charts that go into a PowerPoint, use Copilot or ChatGPT. For quick exploratory visualization to understand your data first, Claude's artifact feature is surprisingly fast.

💬 ChatGPT: Instant 🔵 Claude: Sonnet

!! DATA GOVERNANCE: If the data you are charting is confidential, use Copilot only — it is covered under Microsoft's EDP. Do not upload confidential data to Claude or ChatGPT.

Data & Excel

Clean messy data (duplicates, errors, formatting)

Claude

BestWrites Power Query or Python cleaning scripts with clear instructions for pasting them in

ChatGPT

GoodCan process and clean data directly using Code Interpreter

Copilot

LimitedBasic formatting help only; not designed for bulk data transformation

💡 Tip: Paste a sample of your messy data into Claude and describe what "clean" looks like. It will write the Power Query M code and give you step-by-step instructions for applying it.

🔵 Claude: Sonnet 💬 ChatGPT: Instant

!! DATA GOVERNANCE: Only paste non-confidential sample data into Claude or ChatGPT to generate the cleaning code. Apply the code yourself in Excel — do not share confidential full datasets. Copilot is approved for confidential data.

Writing & Summarization

Draft an executive summary or briefing

Claude

BestMost polished, audience-aware prose; avoids AI-sounding language; follows complex formatting instructions precisely

ChatGPT

GoodTends to produce slightly more formulaic structure; works well for standard formats

Copilot

GoodBest if you need it drafted in Word and want to pull in context from a Teams meeting or SharePoint doc

💡 Tip: Tell Claude who the reader is: "Write an executive summary for our CFO — 3 paragraphs, no jargon, focus on decision points not methodology."

🔵 Claude: Sonnet 💬 ChatGPT: Instant

Writing & Summarization

Summarize a long document or PDF

Claude

BestLargest context window — reads entire 100-page reports without losing detail from earlier pages

ChatGPT

GoodCan handle long docs but may miss nuance from earlier sections in very long files

Copilot

GoodBest when the document is already in SharePoint or OneDrive — no upload needed

💡 Tip: For very long documents, Claude is the safest bet. Upload the PDF and ask specific questions rather than just "summarize" for more useful outputs.

🔵 Claude: Sonnet — large context window 🧡 Claude: Opus — for very complex 100+ page docs

!! DATA GOVERNANCE: Do not upload confidential Rackspace documents (PDFs, Word files, spreadsheets) to Claude or ChatGPT. For confidential documents, use Copilot in Word or Teams — it is covered under Microsoft's EDP.

Writing & Summarization

Write or draft a professional email

Claude

BestBest for sensitive or high-stakes emails — handles tone, nuance, and complex situations with care

ChatGPT

GoodGood for standard professional emails; fast and reliable

Copilot

BestFastest path when you're in Outlook — can reference prior email thread context automatically

💡 Tip: Copilot wins for speed in Outlook. Use Claude when the email is sensitive, involves difficult dynamics, or needs to sound genuinely human rather than templated.

🔵 Claude: Sonnet ⚡ Claude: Haiku — quick routine emails

Writing & Summarization

Edit or improve existing writing

Claude

BestGives the most thoughtful editorial feedback; preserves your voice while improving quality

ChatGPT

GoodCan over-polish — sometimes strips personality from the writing

Copilot

GoodFast for grammar and spelling corrections directly in Word

💡 Tip: Try: "Rewrite this to sound more confident and executive-level without adding length or changing my meaning." Claude will nail this; Copilot may struggle with the nuance.

🔵 Claude: Sonnet ⚡ Claude: Haiku — quick grammar/polish

Writing & Summarization

Summarize meeting notes or create an agenda

Claude

BestProduces clean, action-oriented summaries with clear owner/next step structure

ChatGPT

Good

Copilot

BestCan summarize a Teams meeting directly from the transcript — no copy-paste required

💡 Tip: Use Copilot if it was a Teams meeting. For notes from other sources (Zoom, in-person), paste the transcript into Claude for the cleanest action-item summary.

⚡ Claude: Haiku — fast meeting summaries 🔵 Claude: Sonnet — longer complex transcripts

Coding & Automation

Write a PowerShell or automation script

Claude

BestWrites clean, well-commented scripts even for non-coders; explains what every line does

ChatGPT

Good

Copilot

LimitedNot designed for scripting outside Microsoft's Power Automate ecosystem

💡 Tip: Describe what you want to happen in plain English. Claude will ask clarifying questions if needed and include security notes — especially useful for scripts that touch systems data.

🔵 Claude: Sonnet 🧠 Extended Thinking — for complex multi-step scripts

Coding & Automation

Create an Excel VBA macro

Claude

BestBest inline comments to explain each section; makes it easier to maintain and hand off later

ChatGPT

BestEqually capable; may be faster for simple macros

Copilot

LimitedVBA generation is not a Copilot strength; use Claude or ChatGPT then paste the code in

💡 Tip: Note that the ChatGPT Excel add-in does not support VBA yet (beta limitation). Build macros in the Claude or ChatGPT standalone chat, then paste into Excel's Visual Basic editor.

🔵 Claude: Sonnet 💬 ChatGPT: Instant

Coding & Automation

Build a Power Query data transformation

Claude

BestWrites full M code with step-by-step instructions for pasting into Power Query editor

ChatGPT

Good

Copilot

LimitedNot a strength; use Claude or ChatGPT for M code generation

💡 Tip: Describe your source format (e.g., "Workday export with headers in row 3") and your target format. Claude will write the complete M code and tell you exactly where to paste it.

🔵 Claude: Sonnet

!! DATA GOVERNANCE: Describe your data structure to Claude or ChatGPT in general terms only — do not paste confidential records. Apply the generated code yourself in Excel's Power Query editor.

Coding & Automation

Debug broken code or fix a formula error

Claude

BestExceptional at diagnosing root causes and explaining the fix clearly — not just patching the symptom

ChatGPT

Good

Copilot

LimitedHelpful for obvious errors but struggles with complex formula debugging

💡 Tip: Paste both the broken code AND the error message you're seeing. Claude is significantly better when it has the full context of what's failing.

🔵 Claude: Sonnet 🧠 Extended Thinking — for tricky bugs that defy obvious fixes

!! DATA GOVERNANCE: When sharing code or formulas for debugging, remove or replace any confidential values with dummy data before pasting into Claude or ChatGPT.

Research & Web Search

Search the web for current news or live data

Claude

GoodHas web search capability but not always default behavior — explicitly ask "search the web for…"

ChatGPT

BestLive browsing is a core feature; consistently searches before answering time-sensitive questions

Copilot

BestPowered by Bing — excellent real-time results; best option if you're in Edge browser

💡 Tip: For breaking news and current market data, Copilot and ChatGPT are more reliable. For research that needs deeper analysis after the search, Claude is the better follow-up tool.

🔍 Turn on Web Search — Claude & ChatGPT 💬 ChatGPT: Instant (auto-searches)

Research & Web Search

Conduct deep research — multi-source synthesis

Claude

BestDeep Research mode runs multi-step searches and produces structured, cited reports; nuanced analysis

ChatGPT

BestAlso has Deep Research; excellent for competitive analysis and industry benchmarks

Copilot

GoodGood for quick lookups; less capable for multi-step research synthesis

💡 Tip: Use Deep Research mode for vendor comparisons, industry benchmarking, and board presentation background research. Both Claude and ChatGPT do this well — try both and compare outputs.

🔍 Turn on Web Search — both tools 🔵 Claude: Sonnet (Deep Research) 💭 ChatGPT: Thinking — for complex synthesis

PowerPoint

Create a new PowerPoint deck from scratch

Claude

GoodCannot create an actual .pptx file — drafts content and structure you then paste into your template

ChatGPT

GoodAlso primarily drafts content; full .pptx creation requires a third-party plugin

Copilot

BestOnly tool that creates a complete, branded .pptx file natively — outputs directly into PowerPoint

💡 Tip: Use Claude to draft all your content and structure first, then ask it to "write me a Copilot prompt to build this as a PowerPoint deck." Paste that prompt into Copilot to get the actual file.

🔵 Claude: Sonnet — content drafting 💬 ChatGPT: Instant — content drafting

!! DATA GOVERNANCE: Do not paste or upload confidential Rackspace content into Claude or ChatGPT when drafting slide content. Use Copilot in PowerPoint for presentations containing confidential data — it is covered under Microsoft's EDP.

PowerPoint

Write slide content, bullets, or talking points

Claude

BestMost executive-ready copy; follows tight formatting rules (word limits, parallel structure, no jargon)

ChatGPT

GoodTends to write longer bullets; may need follow-up prompts to tighten

Copilot

GoodBetter at generating than refining; less responsive to nuanced formatting instructions

💡 Tip: "Write 3 insight-led bullets for a CFO audience about [topic]. Max 10 words each. Start each with a strong verb." Claude follows this kind of instruction reliably; Copilot may need the prompt written for it first.

🔵 Claude: Sonnet ⚡ Claude: Haiku — quick bullet generation

PowerPoint

Write speaker notes for existing slides

Claude

BestProduces confident, natural-sounding notes that sound like a real person — not scripted AI

ChatGPT

Good

Copilot

BestCan generate notes directly within PowerPoint for selected slides — no copy-paste required

💡 Tip: Paste your slide titles and bullets into Claude and say: "Write speaker notes for each slide. Conversational tone, 3-4 sentences each, as if I'm presenting to the CFO's leadership team."

🔵 Claude: Sonnet ⚡ Claude: Haiku — quick notes on simple slides

PowerPoint

Sharpen slide headlines for executive impact

Claude

BestTransforms passive topic titles into insight-led statements; understands executive communication norms

ChatGPT

Good

Copilot

LimitedNot as responsive to nuanced rewriting instructions — better suited for content generation than refinement

💡 Tip: "Rewrite these slide titles to be insight-led. Instead of 'Q3 Results,' write something like 'Q3 Revenue Grew 12% Despite FX Headwinds.' Same style for all." Claude will apply it consistently.

🔵 Claude: Sonnet ⚡ Claude: Haiku — fast title rewrites

🔍

No tasks match your search. Try a different keyword or browse a category.

Copy-and-paste prompt templates to get great results from each AI tool. Replace the [highlighted placeholders] with your own details.

📊 Data & Excel

Analyze a Spreadsheet Claude

I'm uploading a spreadsheet with [describe data, e.g. "Q3 regional sales figures"]. Please: 1. Summarize the key trends 2. Flag any outliers or anomalies 3. Suggest 3 actionable insights for a CFO audience

💡 Attach the file directly — Claude can read Excel and CSV uploads.

Build an Excel Formula ChatGPT

I need an Excel formula that [describe what it should do, e.g. "looks up a value in column B based on a match in column A and returns the result from column D"]. My data is in a sheet called [sheet name], rows 2 through [last row]. Please explain the formula step by step.

Budget vs. Actuals Analysis Claude

Attached are our [month/quarter] budget-vs-actuals files. Please: 1. Calculate variances by line item 2. Highlight anything over [threshold, e.g. "10%"] variance 3. Draft a short executive summary suitable for a CFO review deck

✍️ Writing

Executive Summary Claude

Write an executive summary (max 250 words) for [document or topic]. Audience: [e.g. "CFO and senior finance leadership"] Tone: Professional and concise Include: Key findings, recommendations, and next steps

Email Drafting Copilot

Draft a professional email to [recipient/role] about [topic]. Key points to cover: - [point 1] - [point 2] Tone: [e.g. "direct but collaborative"] Keep it under 150 words.

💡 Use Copilot in Outlook for the best inline email experience.

Summarize a Long Document Claude

Please summarize the attached document. Provide: 1. A one-paragraph overview 2. The top 5 key takeaways as bullet points 3. Any action items or decisions needed Audience: [e.g. "finance team leads"]

🔎 Research

Deep Research Report ChatGPT

Using Deep Research, compile a report on [topic, e.g. "2025 trends in corporate treasury management"]. Include: - Industry benchmarks and statistics - Key players and emerging technologies - Risks and opportunities relevant to a CFO - Sources for all claims Format as a structured report with sections and headers.

💡 Use ChatGPT's Deep Research mode for best results on multi-step research.

Competitive Analysis ChatGPT

Research and compare [company/vendor names] across: - Market position and revenue - Product offerings relevant to [our need] - Pricing models - Strengths and weaknesses Present as a comparison table with a summary recommendation.

⚙️ Coding & Automation

VBA Macro ChatGPT

Write a VBA macro for Excel that [describe what it should do, e.g. "loops through all rows in Sheet1, highlights cells in column C where the value exceeds 10000, and copies those rows to Sheet2"]. Include clear comments explaining each step so a non-developer can follow along.

PowerShell Script Claude

Write a PowerShell script that [describe task, e.g. "scans a folder for CSV files older than 30 days, archives them to a zip, and logs the results"]. Requirements: - Include error handling - Add comments for each section - Make file paths configurable at the top of the script

📽️ PowerPoint

Create Slide Content Copilot

Create a [number]-slide presentation about [topic]. Audience: [e.g. "Board of Directors"] Include slides for: - Executive summary - Key metrics and KPIs - Challenges and risks - Recommendations and next steps Keep bullet points concise (max 6 words each).

💡 Use Copilot in PowerPoint to generate slides directly inside your deck.

Speaker Notes Claude

Here are my slide titles and bullet points for a [presentation topic] presentation: [paste slide content] Write speaker notes for each slide that: - Expand on the bullet points with context and data - Include transition phrases between slides - Keep a confident, conversational tone - Are 60–90 seconds of speaking time per slide

Not all AI models are equal — even within the same tool. This page explains which model to choose inside Claude and ChatGPT for your task, when to turn on Web Search, and when Extended Thinking is worth the extra wait. Copilot doesn't have a model picker, so no decisions needed there.

🧡 Claude Models

Haiku ⚡ Quick

The fastest, lightest model. Best for simple tasks where speed matters more than depth. Uses the least of your monthly limit.

Use when…

Writing or editing a routine email
Summarizing a short meeting transcript
Quick grammar or spelling checks
Simple bullet-point generation
You want an instant answer, not deep analysis

Sonnet 4.6 ✓ Default

Your everyday workhorse — handles 90%+ of tasks with strong reasoning and fast responses. If you're unsure which to pick, start here.

Use when…

Analyzing data or Excel files
Writing executive summaries or long documents
Coding, scripting, or Power Query
Most research and synthesis tasks
Anything that doesn't require deep multi-step reasoning

Opus 4.6 🧠 Power

The deep thinker. Reserve for tasks that genuinely need it — it uses more of your monthly limit. Also powers the Claude for Excel and PowerPoint add-ins automatically.

Use when…

Complex multi-factor financial analysis
Reviewing a 100+ page document in full detail
Multi-step reasoning where being wrong is costly
You're using Claude in the Excel or PowerPoint add-in (auto-selected)
Sonnet's answer feels incomplete or shallow

⚠️ Watch your limit: Opus uses significantly more of your monthly token allowance than Sonnet or Haiku. Use it intentionally — don't leave it selected for routine tasks.

💬 ChatGPT Models

ChatGPT simplified its model lineup significantly in early 2026. There are now just two modes — Instant and Thinking — plus an auto-routing option that chooses for you.

Instant (GPT-5.3) ✓ Default

The fast, capable default for everyday work. ChatGPT will automatically switch to Thinking for complex requests when you leave it on Instant — so it's a smart auto-pilot.

Use when…

Writing, editing, summarizing
Research with web search
Creating charts or data analysis
Most everyday tasks — this handles them well
You're not sure — let it auto-switch as needed

Thinking (GPT-5.4) 🧠 Power

Slower but more thorough. Reasons step-by-step before answering. Use for hard problems where you need the most accurate answer, not the fastest one.

Use when…

Complex multi-step financial or legal analysis
Deep research synthesis from many sources
A problem that stumped Instant
You need to trust the output — not just get something fast

⚡ Features: When to Turn Them On

🔍

Web Search

Available in Claude & ChatGPT

Lets the AI search the internet in real-time before responding. Without it, both Claude and ChatGPT answer from their training data, which has a knowledge cutoff.

Turn ON for…

Current news, market data, or recent events
Checking whether a company, policy, or person's status has changed
Any question where "as of today" matters
Verifying a specific fact or claim

Leave OFF for…

Writing, editing, or summarizing content you provide
Coding, formula writing, or data analysis
Tasks that don't require current information

How to turn it on: In Claude — look for the 🔍 Search icon at the bottom of the chat. In ChatGPT — it's often on by default; look for the globe icon in the message bar.

🧠

Extended Thinking

Available in Claude Sonnet & Opus · ChatGPT Thinking mode

Makes the AI pause and reason through a problem step-by-step before giving you an answer. Responses are slower but significantly more accurate for hard problems.

Turn ON for…

Complex financial models or multi-factor variance analysis
Debugging a script that won't cooperate
Multi-step problems where getting it wrong is costly
When Sonnet gave an answer that felt incomplete

Leave OFF for…

Routine writing, emails, or bullet points
Simple questions with straightforward answers
When you need a fast response, not a deep one

How to turn it on — Claude: Click the brain/thinking icon in the message composer, or select it from the model menu. ChatGPT: Switch to "Thinking" in the model picker drop-down.

📏 Context Window ("Space")

Every conversation has a "space" limit — here's what to do when you hit it

Every AI conversation has a context window — think of it as the total amount of information the AI can hold in its memory at once. As a conversation gets longer, it fills up. When it gets too full, the AI may start forgetting earlier parts of the conversation, give shorter or lower-quality answers, or behave inconsistently. Claude has introduced "Infinite Chats" which largely reduces this problem — but ChatGPT still has limits, and very long Claude sessions can still degrade. The fix is simple: start a fresh conversation and paste in a brief summary of what you were doing.

Signs you're hitting the limitResponses suddenly get shorter or vaguer · The AI seems to "forget" something you said earlier · Answers feel less accurate than earlier in the session

What to doStart a new chat · Begin with: "I was working on [brief description]. Here's the key context: [paste summary]" · Continue from there — quality will reset

Claude context windowVery large — handles hundreds of pages in one session. Infinite Chats feature largely eliminates hard limits for paid users.

ChatGPT context windowSmaller than Claude's. GPT-5.4 Thinking has a ~196K token limit. Long deep research sessions or large file uploads can fill this faster than you'd expect.

Which AI Tool Should I Use?

Quick Recommender