SAM Tokenizer β€” AMFORGE/sam_tokenizer

Official tokenizer for SAM (Structured Action Model) by AMFORGE. Built on NexusBPE, AMEFORGE's in-house tokenization architecture designed for structured action generation across heterogeneous domains.


What it does

A single tokenizer that handles 10 production domains with uniform quality β€” robotics, HTTP / REST APIs, MQTT / IoT messaging, databases, workflow orchestration, e-commerce, autonomous vehicles, smart home, calendar / email, and filesystem operations.

Why it matters

Generic LLM tokenizers shred coordinates and identifiers into fragments:

0.5      β†’  ['0', '.', '5']         (3 tokens)
-1.2     β†’  ['-', '1', '.', '2']    (4 tokens)
8080     β†’  ['8', '0', '80']        (3 tokens)

This destroys numeric precision, balloons sequence length, and forces the model to learn arithmetic from character soup. NexusBPE keeps these atomic by construction, while still compressing prose efficiently.

Generic tokenizer NexusBPE
move to x=0.5 y=-1.2 z=0.8 ~16 tokens ~6 tokens
POST /api/v1/orders ~8 tokens ~3 tokens
GET /users β†’ 404 ~6 tokens ~3 tokens

Lower sequence length β†’ lower latency, lower memory, sharper attention on the parts that matter.


Highlights

  • Vocab size: 12000
  • Atomic guarantees: every coordinate, status code, port, frequency, and angle in the supported ranges encodes to a single token
  • Domain coverage: 10 first-class domains via dedicated marker tokens
  • Schema-conditioned: native support for JSON Schema in-context conditioning
  • Reversible: bit-perfect roundtrip on all structured payloads
  • Deterministic: identical input β†’ identical token IDs across runs
  • Compact: ~3Γ— shorter sequences than generic LLM tokenizers on agentic tasks

Loading

The tokenizer ships as a binary model file. Load it via the lightweight NexusBPE wrapper:

from huggingface_hub import hf_hub_download

class NexusBPE:
    """Minimal loader for SAM / NexusBPE tokenizers."""
    def __init__(self, model_path: str):
        import sentencepiece as _spm   # implementation detail
        self._sp = _spm.SentencePieceProcessor(); self._sp.Load(model_path)
        self.vocab_size = self._sp.GetPieceSize()
        self.pad_id = self._sp.pad_id(); self.eos_id = self._sp.eos_id()
    def encode(self, text: str) -> list[int]:
        return self._sp.EncodeAsIds(text)
    def decode(self, ids) -> str:
        return self._sp.DecodeIds(list(ids))

path = hf_hub_download(repo_id="AMFORGE/sam_tokenizer", filename="sam_tokenizer.model")
tok = NexusBPE(path)

ids = tok.encode('<ROS><TASK>move to x=0.5 y=-1.2 z=0.8</TASK>')
print(f"Tokens: {len(ids)}")
print(f"Roundtrip: {tok.decode(ids)}")

Domain markers

The tokenizer reserves marker tokens for each supported domain so the model can condition its output on the active domain:

Marker Purpose
<ROS> Robotics (ROS / ROS2)
<HTTP> HTTP / REST APIs
<MQTT> MQTT / IoT messaging
<DB> Databases (SQL / NoSQL / Redis)
<WORKFLOW> Workflow orchestration
<ECOMMERCE> E-commerce
<VEHICLE> Autonomous vehicles
<HOME> Smart home
<CAL> Calendar / email
<FILE> Filesystem

Plus structural markers β€” <SCHEMA>, <TASK>, <JSON>, <ACTION>, <META> β€” for schema-conditioned prompting.


Used by

License

APACHE-2.0. Free for research and commercial use. Attribution appreciated.

Citation

@misc{sam_tokenizer_2026,
  title  = {SAM Tokenizer: NexusBPE for Multi-Domain Structured Action Generation},
  author = {AMFORGE},
  year   = {2026},
  url    = {https://huggingface.co/AMFORGE/sam_tokenizer}
}

Built with NexusBPE by AMFORGE β€” https://huggingface.co/AMFORGE

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