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Accept a tokenizer release as a consistent vocabulary, special-token, and chat-template package.
Accept a tokenizer release as a consistent vocabulary, special-token, and chat-template package. A partial update can leave old settings beside new weights while the server still starts. Preserve file manifests and transformation fixtures. This is package integrity, separately from comparing two renderer implementations: first establish that each implementation received the same intended artifact set before diagnosing differences in their behavior.
Define tokenizer state
The tokenizer documentation describes saving complete state with save_pretrained. One vocabulary file is not necessarily the complete tokenizer configuration. Special tokens, normalization, and other settings can live separately and affect IDs. Record tokenizer class and saved files. Where repositories contain alternatives, identify the selected path. Renaming a directory cannot make mixed files a coherent release. Tie each element to an accepted revision or an explicitly documented transformation that another operator can reproduce without guessing its origin.
Check snapshot filtering
The Hub download guide explains how revision and file patterns determine downloaded contents. Narrow filters can omit tokenizer metadata. Do not repair that gap by copying arbitrary JSON from a neighboring model. Compare with the accepted manifest and retrieve the intended files. If tokenizers are distributed separately from weights, preserve both revisions and compatibility evidence. One public model alias cannot identify the actual combination used after local directory edits. The artifact record should expose those independent identities.
Preserve the chat template
The chat-templating guide explains sequence formation and interaction with special tokens. Include the template even when an operator maintains an override. Record source and hash rather than calling a custom override the unchanged repository default. Distinguish intentional template changes from accidental file mixing. The former requires updated fixtures; the latter violates the accepted package. Successful generation alone cannot reveal which template was actually used during input preparation. Preserve the effective selection with the file inventory.
Create release fixtures
Build a table of file, source revision, hash, and purpose. Add Unicode text, whitespace-bearing input, and a multi-role conversation. Keep token IDs, decoded round trips, and rendered prompts. These fixtures do not promise that every normalization is perfectly reversible. Record intended round-trip differences explicitly. Updating one file should reveal a deviation before operators compare answer quality or investigate GPU computation. This makes a package inconsistency observable through both identity and behavior instead of relying on apparently plausible output.
Validate delivery and rollback
Check the manifest after transfer and before serving, then run fixtures through the selected loader. File presence in an unused directory does not prove application. Restore tokenizer artifacts with model and template overrides during rollback. The report should identify delivered files, runtime selection, and validated transformations. Equal vocabulary size does not establish cross-model compatibility. Repeat fixtures after framework changes: checksums establish unchanged bytes, while execution verifies that the intended loader path actually uses them. Both are needed to prevent hidden ID and role-marker changes behind an unchanged API name.
Related reading
Reproducible inference stacks: preserving a GPU pilot’s result; Updating an LLM on a GPU: testing a new version with a small rollout.