# letter-counting-legacy-rl

> Legacy letter-counting RL protocol: first 64 generated tasks train, next 64 held out.

Source: https://nodus-platform-site.pages.dev/docs/reference/environments/letter-counting-legacy-rl/
Build revision: 211ad9f836655b1c3a2668c4693e442471f28614

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Legacy letter-counting RL protocol: first 64 generated tasks train, next 64 held out.

|Field|Value|
|-|-|
|Reference|`nodus/letter-counting-legacy-rl@1.0.0`|
|Image|`nodus/env-letter-counting-legacy-rl:1.0.0`|
|Publisher|Open-Thought|
|Category|Reasoning|
|Readiness|Research|
|Modes|Train, Evaluate|
|Reward|Scalar|
|Held-out measures|TrainedTask|
|Splits|64 train, 64 test (disjoint by canonical identity)|
|Licenses|code Apache-2.0, data Apache-2.0|
|Source|<https://github.com/open-thought/reasoning-gym>|

## Grading

Completions are graded by the platform, never by the trainer: the trainer submits `{taskId, completion}` batches and the verdicts come back as task events.

|Grader|Kind|What it checks|
|-|-|-|
|`score-answer`|Program|Raw completion scored by pinned Reasoning Gym; only full credit is Correct|

## Sample task

One line of `nodus-env tasks --split test --seed 0`; tasks never carry answers.

```json
{
  "metadata": {
    "family": "letter_counting",
    "systemPrompt": "Reply with the final answer only. Do not restate the question, do not show working, and do not add any words, labels or punctuation around it."
  },
  "prompt": "How many times does the letter \"t\" appear in the text: \"are far more complex than all that In real life every act\"?",
  "taskId": "letter-counting-legacy-rl:test:0:0"
}
```

## Examples

Each example is a TrainingJob template. A baseline is shown only where the example was measured by running it.

|Example|Mode|Runtime|Model|Tasks|Baseline|Trained|Measured on|
|-|-|-|-|-|-|-|-|
|`letter-counting`|Train|`nodus/grpo-lora`|Qwen/Qwen3-1.7B @ `70d244c`|64|not measured|not measured|not measured|

Run one with a server dry-run first:

Terminal window

```console
$ nodus create trainingjob my-run --from-example nodus/letter-counting-legacy-rl:letter-counting --dry-run=server -o estimate
```

```python
import nodus

job = nodus.recipes.TrainingJob.from_example("nodus/letter-counting-legacy-rl:letter-counting")
plan = job.preview()
run = plan.run(max_cost=5)
print(run.wait().summary)
```