[Model] Add Grok-2

[dangoldbj]

Purpose

Add first-class vLLM support for Grok-2 models by extending tokenizer support, model registry resolution, execution wiring, tests, and documentation.

This change is not a config-only enablement. It introduces a tiktoken-based Grok-2 tokenizer with .tok.json loading and Grok-style chat templates, wires Grok-family model configurations into the vLLM loading and execution paths, and ensures compatibility with existing inference behavior.

Targeted tests and documentation updates are included to validate correctness and make Grok-2 usable in vLLM without downstream patches.

Test Plan

• pytest tests/models/language/generation/test_grok.py -k grok
• pytest tests/tokenizers_/test_registry.py -k grok2

Test Result

• Pass

---

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• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
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[github-actions]

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[mergify]

Documentation preview: https://vllm--31847.org.readthedocs.build/en/31847/

[gemini-code-assist]

Code Review

This pull request adds support for the Grok-2 model. The changes are comprehensive, including the model implementation, a new tiktoken-based tokenizer, and updates to documentation and tests. The model logic is cleanly adapted from the existing Grok-1 implementation to support both models. The new tokenizer for Grok-2 is also well-implemented. I've identified a couple of high-severity issues related to silent error handling in the new tokenizer, which could lead to incorrect behavior without any warning to the user. Addressing these will improve the robustness and debuggability of the new tokenizer.

[dangoldbj]

cc @mgoin

[mergify]

Hi @dangoldbj, the pre-commit checks have failed. Please run:

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[mergify]

Hi @dangoldbj, the pre-commit checks have failed. Please run:

uv pip install pre-commit
pre-commit install
pre-commit run --all-files

Then, commit the changes and push to your branch.

For future commits, pre-commit will run automatically on changed files before each commit.

Tip

Is mypy or markdownlint failing?

mypy and markdownlint are run differently in CI. If the failure is related to either of these checks, please use the following commands to run them locally:

# For mypy (substitute "3.10" with the failing version if needed)
pre-commit run --hook-stage manual mypy-3.10
# For markdownlint
pre-commit run --hook-stage manual markdownlint

[dangoldbj]

@DarkLight1337 @ywang96 @mgoin Added Grok‑2 support (tiktoken tokenizer.tok.json tokenizer + Grok1/Grok2 model plumbing/weight mapping tweaks) and included registry/docs updates. I would appreciate a review.

[DarkLight1337]

Thanks, any chance you can add some e2e tests for ensuring correctness?

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @dangoldbj.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[dangoldbj]

Thanks, LGTM now

@DarkLight1337 Thanks for the review! Appreciate it!

[dangoldbj]

@DarkLight1337 Looks like the current Buildkite failures are likely infra/env, not from this PR’s diff.

• buildkite/ci/pr fails in 2 Node Tests (4 GPUs) with ROCM_HOME: unbound variable in .buildkite/scripts/run-multi-node-test.sh.
• buildkite/amd-ci fails during collection of tests/entrypoints/test_grpc_server.py with ImportError: cannot import name 'vllm_engine_pb2' from 'vllm.grpc'.

This PR only touches Grok model/tokenizer + docs/tests. OK to merge/ignore?

[DarkLight1337]

They are unrelated so we can merge.