docs/source-cards/fixture.md

metadata

tags:
  - mic
  - test-artifact
base_model: google/gemma-3-4b-it

Slim fixture: mic-gemma3-slim

A 17.2M-parameter fixture for the gemma3 MIC, covering google/gemma-3-4b-it. It is a test artifact, not a usable model, tagged test-artifact to keep it out of candidate-model search.

• Fixture key 8d221be0a487. It covers every checkpoint whose processor files are byte-identical and whose config matches after shrinking.
• Same architecture, smaller config: Gemma3ForConditionalGeneration, shrunk by the generic rule in sweep.py (text num_hidden_layers 2, vision num_hidden_layers 2).
• Processor files copied byte for byte from google/gemma-3-4b-it: added_tokens.json, chat_template.json, generation_config.json, preprocessor_config.json, processor_config.json, special_tokens_map.json, tokenizer.json, tokenizer.model, tokenizer_config.json.
• Random weights (seed 17). They passed the input-sensitivity gate: every perturbation of the contract's inputs moved the logits by at least 0.001 (weakest: attention_mask:all_ones, 0.206), so no training was needed.
• Same tensor names as the real checkpoint. The real checkpoint has every parameter, and so does the fixture.
• Saved in bfloat16, the dtype google/gemma-3-4b-it loads in by default.
• Finite in float32, bfloat16, and float16 (forward, loss, gradients).

Built by build_fixtures.py; build.json records the pinned sources, gate results, and file hashes. The source repository commits only README.md and build.json; rebuild the other files with python example/build_fixtures.py --fixture mic-gemma3-slim.