`logprobs` is a mode where LLMs return the probability of each token. `topLogProbs` also returns list list of alternate tokens
and their log probabilities. This can be useful for debugging and understanding the model's behavior.
- See [OpenAI Logprobs](https://cookbook.openai.com/examples/using_logprobs)
:::note
The `logprobs` feature is not available in all models or providers.
:::
## Logprobs
You can enable logprobs in the following ways:
- Use the `logprobs` flag on the run command
```sh
npx genaiscript run ... --logprobs
```
- add the `logprobs` flag to the `script` metadata
```js "logprobs: true"
script({ logprobs: true, ...})
```
### Colored output
When `logprobs` is enabled, the [cli](/genaiscript/reference/cli) will color the output based on the probability of each token.
Blue color indicates high probability and red color indicates low probability.
Here is an example of logprobs in action when running a poem prompt with gpt-4o.
---
In
the
whisper
of
trees
,
the
night
softly
speaks
,
Where
the
moon
light
we
aves
through
the
shadows
it
seeks
.
Stars
tw
inkle
above
,
like
dreams
far
away
,
Painting
the
night
with
the
dawn
's
gentle
sway
.
---
## Top logprobs
You can enable `top-logprobs` in the following ways:
- Use the `top-logprobs` flag on the run command. It enables `logprobs` as well.
```sh
npx genaiscript run ... --top-logprobs 4
```
- add the `topLogprobs` flag to the `script` metadata
```js "logprobs: true"
script({ topLogProbs: 4, ...})
```
### Colored output
When `top-logprobs` are enabled, the console window is colored with the [entropy](https://people.math.harvard.edu/~ctm/home/text/others/shannon/entropy/entropy.pdf) of the alternate tokens.
---
In
the
whisper
of
trees
,
the
night
softly
speaks
,
Where
the
moon
light
we
aves
through
the
shadows
it
seeks
.
Stars
tw
inkle
above
,
like
dreams
far
away
,
Painting
the
night
with
the
dawn
's
gentle
sway
.
---
### Alternate tokens
The trace contains a rendering of the alternate tokens with colored output based on the logprobs.
---
---