
We’ve all been there. You open ChatGPT, Claude, Copilot or Gemini and ask., “What’s the best way to improve my campaign?” Within seconds you get a confident list of suggestions. The answer sounds right, but you’re not sure how it got there, so you roll with it because it’s fast and convenient.
That’s because the options in that drop-down don’t all think the same way. Fast models work like a GPS. They get you somewhere useful quickly, but they rarely explain why one route was chosen over another. Reasoning models behave more like strategists. They break problems into steps, weigh different paths, use tools and data, and check their own work before answering. That means clearer, more structured outputs that line up with your input.
The label that confuses most people is the one that says “Thinking.” Is it worth switching on? Does it use more credits? It depends on the task, and many teams use it, or skip it, in the wrong places. Every major provider now has a family of tiers, and many let you set how much effort the model spends. Matching the tier and the effort to the task is what separates a vague, generic strategy proposal from a useful one.
Chain-of-thought (CoT) started as a prompting technique. Early AI users discovered that explicitly asking models to reason through a problem often improved results. Users told the AI to “think step by step” to improve results on complex, multi-step tasks. If you asked a fast model, “What’s the right positioning for our Q4 sustainability campaign?” and added “Think step by step,” it might produce a breakdown like:
That improved the output, but the model was still generating those steps by predicting what comes next. It wasn’t verifying that each step mattered for your audience or goals, so the result could still feel generic or miss key context.
Today’s reasoning models do that work internally, so the control has moved from your wording to a setting. OpenAI retired ChatGPT’s old Instant/Thinking/Pro mode picker on August 6, replacing it with a thinking-effort control that runs from Instant through Medium, High and Extra High, all on GPT-6 Sol, with a separate Pro option powered by Astra.


Anthropic’s new Haiku 5.5 is the first Haiku with an adjustable effort setting, offering five levels with Medium as the default. Prompting guidance for 2026 reflects the shift: depth of reasoning has become a dial rather than a sentence, with effort settings and context structure as the main levers, and OpenAI’s own guidance discourages “think step by step” prompts on reasoning models.

The practical upshot is that you can buy thinking by the task. The same model can handle a caption at low effort and a product-recall response plan at high effort.
You don’t need deep reasoning for every task. Using it for simple outputs is overkill, and planning how to write a social caption doesn’t need that level of analysis. Reasoning pays off when a task needs structured thinking, multi-step logic and clear justification, particularly when you’re making decisions, analysing complex data or communicating layered insights to stakeholders.
When you’re evaluating campaign options, channel strategies or crisis responses, reasoning models can map risks, simulate outcomes and help you choose a path before launch.
All models can find patterns in data, but reasoning models connect more data points at once and explain why.
For post-campaign reports, RFPs or executive decks, reasoning models help structure complex content into clear, actionable insight.
Reasoning models can turn research, audience insight and competitor analysis into prioritised action plans.
Statements, quotes, claims and anything going to a journalist or a board belong here. Models differ in how they fail, and independent testing of Gemini 4 Argon, for example, found a 15% hallucination rate on AA-Omniscience, which measures wrong answers against honest “I don’t know” responses. Argon isn’t generally available yet, since access is being staged, but it shows why accuracy should be part of model selection. Whichever model you use, ask it to separate what comes from your sources from what it’s inferring.
For quick, low-complexity work, a deep model is like overthinking the problem. Use a fast tier, or turn the effort dial down, with options such as:
Good use cases for fast tiers in marketing and comms:
For everything else, where you need clear structure and deeper insight, use a reasoning tier (see the table below).
Most teams don’t pick the wrong model on purpose. They leave the default on, or they use one setting for everything. These are the five mismatches that show up most.
Start with the task, then pick the tier.
Prompting a reasoning model well gets you structured, actionable output aligned with your goals. These models reason internally, but the quality of what you get still depends on how you frame the request.
For example, instead of asking, “Explain step by step how to improve my campaign,” try Role, Task, Context prompting:
“As a marketing strategist (Role), review our Q3 campaign results and develop an actionable plan to improve performance next quarter (Task), structured for stakeholder presentation (Format). Flag any recommendation the data doesn’t support.”
Or:
“As a brand strategist (Role), using the brand guidelines and past campaign data provided (Context), create a positioning framework with three options and the pros and cons of each (Task), formatted for a stakeholder presentation (Format).”
An additional prompt to include help to audit the response:
What assumptions did you make, and where is this most likely to be wrong?
This single question often reveals unsupported claims, weak reasoning and missing context before content reaches stakeholders.
Reasoning mode isn’t something to switch on for everything or to avoid altogether. It’s a tool for the tasks where depth changes the answer. Before you pick a model or a thinking level, ask what happens if the output is wrong. If the answer is “not much,” go fast and cheap. If it’s “it becomes public,” go deep and keep a person in the loop. That one question catches most wrong-model mistakes.
Need help selecting the right AI tools, governance approach or workflow for your communications team? Get in touch to discuss model selection, implementation and training.

AI Thinking Mode is a reasoning capability that allows an AI model to spend more time analysing a problem before generating a response. Rather than producing an immediate answer, the model evaluates options, checks assumptions and works through complex decisions before responding.
Reasoning models prioritise accuracy, analysis and problem solving, while fast models prioritise speed and efficiency. Fast models are typically better for drafting content, brainstorming ideas and handling routine tasks. I.e. less overthinking! Reasoning models are better for strategic decisions, research, planning and high-stakes communications.
Often, yes. Reasoning models are designed to allocate additional computational effort to analysing information and evaluating potential answers. However, they can still make mistakes and should not replace human judgment, particularly for business, legal or regulatory decisions.
Reasoning models may reduce certain types of hallucinations because they spend more time evaluating information before responding. However, hallucinations can still occur, especially when the model lacks relevant data or is asked to make assumptions.
Neither is universally better. Fast models are generally better for speed, content generation and everyday tasks. One of the models we've used that is considered to be a 'fast model' has performed well in the more complex tasks of analysis. *DeepSeek-V4.1-Flash is primarily a fast model optimised for speed, efficiency and high-throughput workloads. However, unlike many traditional fast models, it includes configurable reasoning effort, allowing users to trade speed for deeper analysis on more complex tasks.
Reasoning models are generally better for analysis, planning, decision-making and complex problem solving. The best choice depends on the importance, complexity and risk associated with the task.