Model Settings
Parameters like temperature, top_p, max length, and stop sequences
Try the "Parameter Lab" at the top of the page to see how temperature changes affect generation results in real time.
Prompts are the "instructions" you give to AI. Parameters are the AI's "personality settings." In production, tweaking these parameters often fixes "unstable output" problems faster than rewriting your prompt.
1. The Creativity Engine: Temperature vs. Top_p
The key insight here: AI doesn't understand word meanings. It's just doing probability prediction.
Temperature (Sampling Temperature)
Under the hood: When picking the next token, the model scales the probability distribution across its entire vocabulary.
- Low temperature (T -> 0): "Probability amplifier." High-probability tokens get even higher, low-probability ones basically vanish. The model becomes extremely conservative, always picking the safest word.
- High temperature (T -> 1.5+): "Probability equalizer." Lower-probability tokens get a real shot. The model becomes adventurous -- output gets more surprising and creative.
Practical rules:
- Need accuracy (writing code, extracting JSON): Lock it at
0.0. - Need diversity (writing fiction, brainstorming names): Try
1.2or higher.
Top_p (Nucleus Sampling)
Under the hood: Sort tokens by probability, then only sample from the smallest set whose cumulative probability exceeds P.
- What it does: Acts as a "noise filter."
- Use case: Setting
Top_p = 0.1means the AI won't touch tokens in the bottom 90% of the probability distribution, even in "creative mode."
Parameter tuning rules of thumb:
- Don't crank both at the same time.
- Adjust Temperature first. If the AI starts producing gibberish (grammar errors, nonsense), lower Top_p to filter out long-tail noise.
2. Presence and Diversity: Penalties
When the AI gets stuck in loops or keeps using the same words, these are your surgical tools:
- Presence Penalty: "Topic expander." Once a token has appeared, it gets penalized. This forces the AI to bring up new topics, increasing the "breadth" of the text.
- Frequency Penalty: "Vocabulary enricher." The more a token appears, the heavier the penalty. This forces the AI to use synonyms, increasing the "texture" of the text.
3. Length and Boundaries (Constraints)
Context Window -- a core 2026 concept
In 2026, mainstream models (Gemini 3, GPT-5) support million-token or even unlimited context. But you still need to watch out:
- Lost in the Middle: Models tend to have the weakest recall for content in the middle of long texts.
- Cost control: Longer context means inference cost (and latency) grows exponentially or linearly.
- Max Output Tokens: This only limits the reply length -- it doesn't affect how much the model can "see."
Stop Sequences
These aren't just for preventing AI rambling -- they're logic control.
- Pro tip: In few-shot prompting, set
\nas a stop sequence to force the AI to generate only one line at a time. Great for batch data generation.
The Parameter Mental Model: Dashboard Method
We split tasks into three "quadrants" -- find yours:
Quadrant A: Hard Logic (Code, Logic, Math)
- Config: Temp:
0.0, Top_p:1.0, Penalty:0.0 - Mindset: You're a strict instructor. 1+1 must equal 2. Zero randomness allowed.
Quadrant B: Content Creation (Email, Summary, Translation)
- Config: Temp:
0.7, Top_p:0.9, Penalty:0.1 - Mindset: You're an editor-in-chief. You want smooth prose with professional depth and enough variation to not sound robotic.
Quadrant C: Creative Explosion (Brainstorming, Fiction)
- Config: Temp:
1.3, Top_p:1.0, Penalty:0.5 - Mindset: You're the client saying "show me something I haven't seen before" -- and you're okay with the occasional miss.
Advanced: Scientific Parameter Tuning
- Control your variables: Keep the prompt constant, only change parameters.
- Fix the Seed: During testing, use a fixed
Seedvalue so you know improvements come from parameter changes, not random luck. - Parallel sampling: At
Temperature = 1.0, usen > 1(generate multiple results at once) and pick the best one.
Next up: Now that you've got the "personality settings" down, we're heading into the real arena -- Core Techniques, where you'll learn how prompt structure directly changes how AI thinks.