ReasonerGrammarObject wraps an inner grammar, but disaggregated prebuilt replay checks the wrapper current_token to avoid accepting an already accepted token twice. Track the token on the wrapper itself so reasoning grammar follows the same contract as XGrammar.
Speculative decode can accept a stop string and EOS in one step. Check stop strings before token-based EOS after sanitizing invalid token ids, and set finished_len at the matched stop position so trailing accepted tokens do not leak.
Constraint: Current branch predates upstream helper methods for locating string stop positions, so the stop-string fix is manually ported instead of cherry-picked.
Rejected: Direct cherry-pick of bbc853df46 | current schedule_batch.py lacks the upstream helper context.
Confidence: high
Scope-risk: moderate
Directive: Keep vocab-boundary sanitization before string decoding; do not move token-based EOS ahead of stop-string checks without a same-step speculative regression test.
Tested: RED/GREEN remote pytest in cjy-glm5-new for constrained current_token and stop-string speculative tests
Tested: git diff --check; py_compile for reasoner_grammar_backend.py and schedule_batch.py
Not-tested: Full scheduler/disaggregation integration suite
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