feat: add max_tokens_per_doc in rerank request. (#38827)

Signed-off-by: Jesus Federico <jefp@amazon.com>
Signed-off-by: wang.yuqi <yuqi.wang@daocloud.io>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: wang.yuqi <yuqi.wang@daocloud.io>

tests/entrypoints/pooling/scoring/test_cross_encoder_offline.py

@@ -112,6 +112,35 @@ def test_classify(llm):
     assert len(outputs[0].outputs.data) == 1
 
 
+@pytest.mark.skip_global_cleanup
+def test_max_tokens_per_doc(llm: LLM):
+    """Test max_tokens_per_doc via PoolingParams.extra_kwargs (offline)."""
+    long_doc = "The capital of France is Paris. " * 20
+
+    # Without truncation
+    outputs_no_limit = llm.score(
+        TEXTS_1[0],
+        long_doc,
+        use_tqdm=False,
+    )
+
+    # With truncation via extra_kwargs
+    outputs_with_limit = llm.score(
+        TEXTS_1[0],
+        long_doc,
+        pooling_params=PoolingParams(extra_kwargs={"max_tokens_per_doc": 10}),
+        use_tqdm=False,
+    )
+
+    assert len(outputs_no_limit) == 1
+    assert len(outputs_with_limit) == 1
+
+    # Truncated version should have fewer prompt tokens
+    no_limit_tokens = len(outputs_no_limit[0].prompt_token_ids)
+    with_limit_tokens = len(outputs_with_limit[0].prompt_token_ids)
+    assert with_limit_tokens < no_limit_tokens
+
+
 def test_pooling_params(llm: LLM):
     def get_outputs(use_activation):
         outputs = llm.score(

tests/entrypoints/pooling/scoring/test_cross_encoder_online.py

@@ -471,6 +471,78 @@ async def test_pooling_token_classify(server: RemoteOpenAIServer):
     assert len(poolings.data[0].data[0]) == 1
 
 
+@pytest.mark.asyncio
+async def test_rerank_max_tokens_per_doc(
+    server: RemoteOpenAIServer,
+):
+    """Test that max_tokens_per_doc actually reduces the token count."""
+    query = "What is the capital of France?"
+    # Use a doc that fits within max_model_len=100 (query ~8 tokens + 4 special)
+    long_doc = "The capital of France is Paris. " * 10  # ~70 tokens
+
+    # Without max_tokens_per_doc
+    response_no_limit = requests.post(
+        server.url_for("rerank"),
+        json={
+            "model": MODEL_NAME,
+            "query": query,
+            "documents": [long_doc],
+            "truncate_prompt_tokens": 99,
+        },
+    )
+    response_no_limit.raise_for_status()
+    rerank_no_limit = RerankResponse.model_validate(response_no_limit.json())
+
+    # With max_tokens_per_doc
+    response_with_limit = requests.post(
+        server.url_for("rerank"),
+        json={
+            "model": MODEL_NAME,
+            "query": query,
+            "documents": [long_doc],
+            "max_tokens_per_doc": 10,
+        },
+    )
+    response_with_limit.raise_for_status()
+    rerank_with_limit = RerankResponse.model_validate(response_with_limit.json())
+
+    assert rerank_with_limit.usage.prompt_tokens < rerank_no_limit.usage.prompt_tokens
+
+
+@pytest.mark.asyncio
+async def test_rerank_max_tokens_per_doc_validation(
+    server: RemoteOpenAIServer,
+):
+    """Test that max_tokens_per_doc validation works correctly."""
+    query = "What is the capital of France?"
+    documents = ["The capital of France is Paris."]
+
+    # Test with max_tokens_per_doc=0 (should succeed — means no truncation)
+    response = requests.post(
+        server.url_for("rerank"),
+        json={
+            "model": MODEL_NAME,
+            "query": query,
+            "documents": documents,
+            "max_tokens_per_doc": 0,
+        },
+    )
+    response.raise_for_status()
+
+    # Test with invalid max_tokens_per_doc (negative)
+    response = requests.post(
+        server.url_for("rerank"),
+        json={
+            "model": MODEL_NAME,
+            "query": query,
+            "documents": documents,
+            "max_tokens_per_doc": -5,
+        },
+    )
+    assert response.status_code == 400
+    assert "max_tokens_per_doc must be a non-negative integer" in response.text
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize("task", ["embed", "token_embed", "plugin"])
 async def test_pooling_not_supported(server: RemoteOpenAIServer, task: str):

tests/models/language/pooling/test_max_tokens_per_doc.py

+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""
+Tests for max_tokens_per_doc and max_tokens_per_query.
+"""
+
+import json
+import os
+from dataclasses import dataclass
+
+import pytest
+import requests
+
+from tests.utils import VLLM_PATH, RemoteOpenAIServer
+from vllm.entrypoints.pooling.scoring.protocol import RerankResponse
+
+os.environ["VLLM_LOGGING_LEVEL"] = "WARNING"
+
+TEMPLATE_DIR = str(VLLM_PATH / "examples/pooling/score/template")
+
+long_query = "What is the capital of France?" * 20
+long_doc = "The capital of France is Paris. " * 20
+
+
+@dataclass
+class TestConfig:
+    model: str
+    args: list[str]
+    without_truncated_prompt_tokens: int
+    with_max_tokens_per_query_prompt_tokens: int
+    with_max_tokens_per_doc_prompt_tokens: int
+    with_max_tokens_per_query_and_doc_prompt_tokens: int
+
+
+RERANK_CONFIGS = [
+    # 1. cross-encoder
+    TestConfig(
+        model="jinaai/jina-reranker-v2-base-multilingual",
+        args=[
+            "--enforce-eager",
+            "--max-model-len",
+            "1024",
+            "--trust-remote-code",
+        ],
+        without_truncated_prompt_tokens=284,
+        with_max_tokens_per_query_prompt_tokens=154,
+        with_max_tokens_per_doc_prompt_tokens=154,
+        with_max_tokens_per_query_and_doc_prompt_tokens=24,
+    ),
+    # 2. cross-encoder + score template
+    TestConfig(
+        model="Qwen/Qwen3-Reranker-0.6B",
+        args=[
+            "--enforce-eager",
+            "--max-model-len",
+            "1024",
+            "--hf-overrides",
+            json.dumps(
+                {
+                    "architectures": ["Qwen3ForSequenceClassification"],
+                    "classifier_from_token": ["no", "yes"],
+                    "is_original_qwen3_reranker": True,
+                }
+            ),
+            "--chat-template",
+            os.path.join(TEMPLATE_DIR, "qwen3_reranker.jinja"),
+        ],
+        without_truncated_prompt_tokens=352,
+        with_max_tokens_per_query_prompt_tokens=223,
+        with_max_tokens_per_doc_prompt_tokens=221,
+        with_max_tokens_per_query_and_doc_prompt_tokens=92,
+    ),
+    # 3. bi-encoder
+    TestConfig(
+        model="intfloat/multilingual-e5-small",
+        args=[
+            "--enforce-eager",
+            "--max-model-len",
+            "512",
+            "--trust-remote-code",
+        ],
+        without_truncated_prompt_tokens=286,
+        with_max_tokens_per_query_prompt_tokens=156,
+        with_max_tokens_per_doc_prompt_tokens=155,
+        with_max_tokens_per_query_and_doc_prompt_tokens=25,
+    ),
+    # 4. late-interaction
+    TestConfig(
+        model="answerdotai/answerai-colbert-small-v1",
+        args=[
+            "--enforce-eager",
+            "--max-model-len",
+            "512",
+            "--trust-remote-code",
+        ],
+        without_truncated_prompt_tokens=285,
+        with_max_tokens_per_query_prompt_tokens=155,
+        with_max_tokens_per_doc_prompt_tokens=155,
+        with_max_tokens_per_query_and_doc_prompt_tokens=25,
+    ),
+    # 5. jinaai/jina-reranker-v3
+    TestConfig(
+        model="jinaai/jina-reranker-v3",
+        args=[
+            "--enforce-eager",
+            "--max-model-len",
+            "1024",
+            "--trust-remote-code",
+        ],
+        without_truncated_prompt_tokens=567,
+        with_max_tokens_per_query_prompt_tokens=308,
+        with_max_tokens_per_doc_prompt_tokens=436,
+        with_max_tokens_per_query_and_doc_prompt_tokens=177,
+    ),
+]
+
+
+@pytest.fixture(scope="module", params=RERANK_CONFIGS, ids=lambda c: c.model)
+def server(request):
+    config: TestConfig = request.param
+    with RemoteOpenAIServer(config.model, config.args) as remote_server:
+        yield config, remote_server
+
+
+def test_without_truncated(server):
+    """Test that max_tokens_per_doc truncates documents correctly."""
+    config, remote_server = server
+
+    response = requests.post(
+        remote_server.url_for("rerank"),
+        json={"model": config.model, "query": long_query, "documents": [long_doc]},
+    )
+    response.raise_for_status()
+    rerank = RerankResponse.model_validate(response.json())
+
+    assert rerank.id is not None
+    assert rerank.results is not None
+    assert len(rerank.results) == 1
+    assert rerank.usage.prompt_tokens == config.without_truncated_prompt_tokens
+
+
+def test_max_tokens_per_query(server):
+    """Test that max_tokens_per_doc truncates documents correctly."""
+    config, remote_server = server
+
+    response = requests.post(
+        remote_server.url_for("rerank"),
+        json={
+            "model": config.model,
+            "query": long_query,
+            "documents": [long_doc],
+            "max_tokens_per_query": 10,
+        },
+    )
+    response.raise_for_status()
+    rerank = RerankResponse.model_validate(response.json())
+
+    assert rerank.id is not None
+    assert rerank.results is not None
+    assert len(rerank.results) == 1
+    assert rerank.usage.prompt_tokens == config.with_max_tokens_per_query_prompt_tokens
+
+
+def test_max_tokens_per_doc(server):
+    """Test that max_tokens_per_doc truncates documents correctly."""
+    config, remote_server = server
+
+    response = requests.post(
+        remote_server.url_for("rerank"),
+        json={
+            "model": config.model,
+            "query": long_query,
+            "documents": [long_doc],
+            "max_tokens_per_doc": 10,
+        },
+    )
+    response.raise_for_status()
+    rerank = RerankResponse.model_validate(response.json())
+
+    assert rerank.id is not None
+    assert rerank.results is not None
+    assert len(rerank.results) == 1
+    assert rerank.usage.prompt_tokens == config.with_max_tokens_per_doc_prompt_tokens
+
+
+def test_max_tokens_per_query_and_doc(server):
+    """Test that max_tokens_per_doc truncates documents correctly."""
+    config, remote_server = server
+
+    response = requests.post(
+        remote_server.url_for("rerank"),
+        json={
+            "model": config.model,
+            "query": long_query,
+            "documents": [long_doc],
+            "max_tokens_per_query": 10,
+            "max_tokens_per_doc": 10,
+        },
+    )
+    response.raise_for_status()
+    rerank = RerankResponse.model_validate(response.json())
+
+    assert rerank.id is not None
+    assert rerank.results is not None
+    assert len(rerank.results) == 1
+    assert (
+        rerank.usage.prompt_tokens
+        == config.with_max_tokens_per_query_and_doc_prompt_tokens
+    )

vllm/entrypoints/pooling/base/serving.py

@@ -232,6 +232,7 @@ class PoolingServingBase(ABC):
                 "greater than max_model_len."
                 " Please request a smaller truncation size."
             )
+
         return None
 
     async def _get_trace_headers(

vllm/entrypoints/pooling/scoring/io_processor.py

@@ -25,8 +25,10 @@ from .typing import ScoreData, ScoreInput, ScoringData
 from .utils import (
     compress_token_type_ids,
     compute_maxsim_score,
+    get_num_special_tokens_for_pair,
     parse_score_data,
     score_data_to_prompts,
+    truncate_text_to_tokens,
     validate_score_input,
 )
 
@@ -48,6 +50,64 @@ class ScoringIOProcessor(PoolingIOProcessor):
     def create_pooling_params(self, request):
         return request.to_pooling_params(self.pooling_task)
 
+    def _validate_token_limit(self, value: int, name: str) -> None:
+        if value < 0:
+            raise ValueError(f"{name} must be a non-negative integer")
+        if value >= self.model_config.max_model_len:
+            raise ValueError(
+                f"{name} ({value}) must be less "
+                f"than max_model_len ({self.model_config.max_model_len})."
+            )
+
+    def _get_token_limits(
+        self,
+        request: ScoringRequest | None = None,
+        pooling_params: PoolingParams | None = None,
+    ) -> tuple[int, int]:
+        """Extract and validate token limits from request or pooling_params."""
+        if request is not None:
+            max_tokens_per_query = getattr(request, "max_tokens_per_query", 0)
+            max_tokens_per_doc = getattr(request, "max_tokens_per_doc", 0)
+        else:
+            extra = (
+                (pooling_params.extra_kwargs or {})
+                if pooling_params is not None
+                else {}
+            )
+            max_tokens_per_query = extra.get("max_tokens_per_query", 0)
+            max_tokens_per_doc = extra.get("max_tokens_per_doc", 0)
+
+        if max_tokens_per_query != 0:
+            self._validate_token_limit(max_tokens_per_query, "max_tokens_per_query")
+        if max_tokens_per_doc != 0:
+            self._validate_token_limit(max_tokens_per_doc, "max_tokens_per_doc")
+        return max_tokens_per_query, max_tokens_per_doc
+
+    def _truncate_scoring_data(
+        self,
+        scoring_data: ScoringData,
+        max_tokens_per_query: int = 0,
+        max_tokens_per_doc: int = 0,
+    ) -> ScoringData:
+        """Truncate query/document texts to token limits."""
+        data_1 = scoring_data.data_1
+        data_2 = scoring_data.data_2
+        if max_tokens_per_query > 0:
+            data_1 = [
+                truncate_text_to_tokens(d, self.tokenizer, max_tokens_per_query)
+                if isinstance(d, str)
+                else d
+                for d in data_1
+            ]
+        if max_tokens_per_doc > 0:
+            data_2 = [
+                truncate_text_to_tokens(d, self.tokenizer, max_tokens_per_doc)
+                if isinstance(d, str)
+                else d
+                for d in data_2
+            ]
+        return ScoringData(data_1=data_1, data_2=data_2)
+
     def valid_inputs(
         self,
         data_1: ScoreInput | list[ScoreInput],
@@ -82,6 +142,15 @@ class BiEncoderIOProcessor(ScoringIOProcessor):
             raise ValueError(f"Invalid {self.name} request type")
 
         scoring_data = self.valid_inputs(data_1, data_2)
+
+        max_tokens_per_query, max_tokens_per_doc = self._get_token_limits(
+            request=request
+        )
+        if max_tokens_per_query > 0 or max_tokens_per_doc > 0:
+            scoring_data = self._truncate_scoring_data(
+                scoring_data, max_tokens_per_query, max_tokens_per_doc
+            )
+
         tok_params = request.build_tok_params(self.model_config)
         engine_inputs = self._pre_process(
             scoring_data,
@@ -112,10 +181,23 @@ class BiEncoderIOProcessor(ScoringIOProcessor):
 
     def pre_process_offline(self, ctx: OfflineInputsContext) -> Sequence[EngineInput]:
         assert isinstance(ctx.prompts, ScoringData)
+        assert not isinstance(ctx.pooling_params, Sequence)
+
         tok_params = self.renderer.default_cmpl_tok_params.with_kwargs(
             **(ctx.tokenization_kwargs or {})
         )
-        return self._pre_process(ctx.prompts, tok_params)
+
+        max_tokens_per_query, max_tokens_per_doc = self._get_token_limits(
+            pooling_params=ctx.pooling_params
+        )
+
+        scoring_data = ctx.prompts
+        if max_tokens_per_query > 0 or max_tokens_per_doc > 0:
+            scoring_data = self._truncate_scoring_data(
+                scoring_data, max_tokens_per_query, max_tokens_per_doc
+            )
+
+        return self._pre_process(scoring_data, tok_params)
 
     def post_process_offline(
         self,
@@ -217,8 +299,38 @@ class LateInteractionIOProcessor(BiEncoderIOProcessor):
 class FlashLateInteractionIOProcessor(LateInteractionIOProcessor):
     name = "flash-late-interaction"
 
-    def _post_process(self, outputs: list[PoolingRequestOutput], n_queries: int):
-        return outputs
+    def post_process_online(
+        self,
+        ctx: ScoringServeContext,
+    ):
+        assert ctx.query_final_res_batch is not None
+        assert ctx.final_res_batch is not None
+        assert isinstance(ctx.n_queries, int)
+
+        # Expand queries if 1:N scoring
+        if len(ctx.query_final_res_batch) == 1:
+            ctx.query_final_res_batch = ctx.query_final_res_batch * len(
+                ctx.final_res_batch
+            )
+
+        final_res_batch: list[PoolingRequestOutput] = []
+        for d1, d2 in zip(ctx.query_final_res_batch, ctx.final_res_batch):
+            padding: list[int] = []
+            if (pad_token_id := self.pad_token_id) is not None:
+                padding = [pad_token_id]
+
+            tokens = d1.prompt_token_ids + padding + d2.prompt_token_ids
+
+            final_res_batch.append(
+                PoolingRequestOutput(
+                    request_id=f"{d1.request_id}_{d2.request_id}",
+                    outputs=d2.outputs,
+                    prompt_token_ids=tokens,
+                    num_cached_tokens=d1.num_cached_tokens + d2.num_cached_tokens,
+                    finished=True,
+                )
+            )
+        ctx.final_res_batch = final_res_batch
 
 
 class CrossEncoderIOProcessor(ScoringIOProcessor):
@@ -255,6 +367,11 @@ class CrossEncoderIOProcessor(ScoringIOProcessor):
             raise ValueError(f"Invalid {self.name} request type")
 
         scoring_data = self.valid_inputs(data_1, data_2)
+
+        max_tokens_per_query, max_tokens_per_doc = self._get_token_limits(
+            request=request
+        )
+
         tok_params = request.build_tok_params(self.model_config)
         pooling_params = self.create_pooling_params(request)
 
@@ -263,6 +380,8 @@ class CrossEncoderIOProcessor(ScoringIOProcessor):
             tok_params,
             pooling_params,
             chat_template=self.chat_template,
+            max_tokens_per_query=max_tokens_per_query,
+            max_tokens_per_doc=max_tokens_per_doc,
             prompt_extras={
                 k: v
                 for k in ("mm_processor_kwargs", "cache_salt")
@@ -283,8 +402,18 @@ class CrossEncoderIOProcessor(ScoringIOProcessor):
         tok_params = self.renderer.default_cmpl_tok_params.with_kwargs(
             **(ctx.tokenization_kwargs or {})
         )
+
+        max_tokens_per_query, max_tokens_per_doc = self._get_token_limits(
+            pooling_params=ctx.pooling_params
+        )
+
         engine_inputs, pooling_params_list = self._pre_process(
-            ctx.prompts, tok_params, ctx.pooling_params, ctx.chat_template
+            ctx.prompts,
+            tok_params,
+            ctx.pooling_params,
+            ctx.chat_template,
+            max_tokens_per_query=max_tokens_per_query,
+            max_tokens_per_doc=max_tokens_per_doc,
         )
         ctx.pooling_params = pooling_params_list
         return engine_inputs
@@ -298,6 +427,8 @@ class CrossEncoderIOProcessor(ScoringIOProcessor):
         tok_params: TokenizeParams,
         pooling_params: PoolingParams | None,
         chat_template: str | None = None,
+        max_tokens_per_query: int = 0,
+        max_tokens_per_doc: int = 0,
         prompt_extras: dict[str, Any] | None = None,
     ) -> tuple[Sequence[EngineInput], list[PoolingParams]]:
         # todo: support prompt_extras
@@ -320,6 +451,8 @@ class CrossEncoderIOProcessor(ScoringIOProcessor):
                 data_2=d,
                 encode_kwargs=tok_params.get_encode_kwargs(),
                 chat_template=chat_template,
+                max_tokens_per_query=max_tokens_per_query,
+                max_tokens_per_doc=max_tokens_per_doc,
             )
 
             if token_type_ids := engine_prompt.pop("token_type_ids", None):
@@ -342,6 +475,8 @@ class CrossEncoderIOProcessor(ScoringIOProcessor):
         data_2: ScoreData,
         encode_kwargs: dict[str, Any],
         chat_template: str | None = None,
+        max_tokens_per_query: int = 0,
+        max_tokens_per_doc: int = 0,
     ):
         model_config = self.model_config
         tokenizer = self.tokenizer
@@ -352,25 +487,61 @@ class CrossEncoderIOProcessor(ScoringIOProcessor):
             model_config,
         )
 
+        # Apply truncation before defining closures
+        if max_tokens_per_query > 0 and isinstance(prompt_1, str):
+            prompt_1 = truncate_text_to_tokens(
+                prompt_1, tokenizer, max_tokens_per_query
+            )
+        if max_tokens_per_doc > 0 and isinstance(prompt_2, str):
+            prompt_2 = truncate_text_to_tokens(prompt_2, tokenizer, max_tokens_per_doc)
+
         def default_tokenizer_encode():
+            local_kwargs = encode_kwargs.copy()
+
             if self.supports_score_template:
                 assert self.model is not None
                 full_prompt = self.model.get_score_template(prompt_1, prompt_2)
                 if full_prompt is None:
                     raise ValueError("Get empty score template from model")
 
-                prompt_inputs = tokenizer(full_prompt, **encode_kwargs)
+                prompt_inputs = tokenizer(full_prompt, **local_kwargs)
             else:
                 if self.use_sep_token:
                     # cross_encoder models defaults to using separating token.
+                    if max_tokens_per_doc > 0 and isinstance(prompt_2, str):
+                        query_tokens = tokenizer.encode(
+                            prompt_1, add_special_tokens=False
+                        )
+                        num_special = get_num_special_tokens_for_pair(tokenizer)
+                        doc_limit_max_length = (
+                            len(query_tokens) + max_tokens_per_doc + num_special
+                        )
+                        existing_max_length = local_kwargs.get("max_length")
+                        if existing_max_length is not None:
+                            effective_max_length = min(
+                                doc_limit_max_length, existing_max_length
+                            )
+                        else:
+                            effective_max_length = doc_limit_max_length
+                        local_kwargs["truncation"] = "only_second"
+                        local_kwargs["max_length"] = effective_max_length
+
                     prompt_inputs = tokenizer(
-                        text=prompt_1, text_pair=prompt_2, **encode_kwargs
+                        text=prompt_1, text_pair=prompt_2, **local_kwargs
                     )
                     full_prompt = tokenizer.decode(prompt_inputs["input_ids"])
                 else:
                     # `llm as reranker` defaults to not using separating token.
+                    if max_tokens_per_doc > 0 and isinstance(prompt_2, str):
+                        query_ids = tokenizer.encode(prompt_1, add_special_tokens=False)
+                        doc_ids = tokenizer.encode(prompt_2, add_special_tokens=False)
+                        doc_ids = doc_ids[:max_tokens_per_doc]
+                        input_ids = query_ids + doc_ids
+                        full_prompt = tokenizer.decode(input_ids)
+                        prompt_inputs = {"input_ids": input_ids}
+                    else:
                         full_prompt = prompt_1 + prompt_2
-                    prompt_inputs = tokenizer(text=full_prompt, **encode_kwargs)
+                        prompt_inputs = tokenizer(text=full_prompt, **local_kwargs)
             return full_prompt, prompt_inputs
 
         # FIXME: For now, we only apply a template when one is explicitly provided.

vllm/entrypoints/pooling/scoring/protocol.py

@@ -20,6 +20,24 @@ from .typing import ScoreContentPartParam, ScoreInput
 
 
 class ScoreRequestMixin(PoolingBasicRequestMixin, ClassifyRequestMixin):
+    max_tokens_per_query: int = Field(
+        default=0,
+        description=(
+            "Maximum number of tokens per query. Queries longer than "
+            "this will be truncated to this length. 0 means no "
+            "query-level truncation is applied."
+        ),
+    )
+    max_tokens_per_doc: int = Field(
+        default=0,
+        description=(
+            "Maximum number of tokens per document. Documents longer than "
+            "this will be truncated to this length. 0 means no "
+            "document-level truncation is applied (only truncate_prompt_tokens "
+            "applies to the combined query+document)."
+        ),
+    )
+
     def build_tok_params(self, model_config: ModelConfig) -> TokenizeParams:
         encoder_config = model_config.encoder_config or {}
 
@@ -91,29 +109,11 @@ ScoreRequest: TypeAlias = (
 )
 
 
-class RerankRequest(PoolingBasicRequestMixin, ClassifyRequestMixin):
+class RerankRequest(ScoreRequestMixin):
     query: ScoreInput
     documents: ScoreInput | list[ScoreInput]
     top_n: int = Field(default_factory=lambda: 0)
 
-    def build_tok_params(self, model_config: ModelConfig) -> TokenizeParams:
-        encoder_config = model_config.encoder_config or {}
-
-        return TokenizeParams(
-            max_total_tokens=model_config.max_model_len,
-            max_output_tokens=0,
-            truncate_prompt_tokens=self.truncate_prompt_tokens,
-            truncation_side=self.truncation_side,
-            do_lower_case=encoder_config.get("do_lower_case", False),
-            max_total_tokens_param="max_model_len",
-        )
-
-    def to_pooling_params(self, task: PoolingTask = "classify"):
-        return PoolingParams(
-            task=task,
-            use_activation=self.use_activation,
-        )
-
 
 ScoringRequest: TypeAlias = ScoreRequest | RerankRequest
 

vllm/entrypoints/pooling/scoring/serving.py

@@ -237,6 +237,7 @@ class ServingScores(PoolingServing):
 
         await self._prepare_generators(query_ctx)
         await self._collect_batch(query_ctx)
+        ctx.query_final_res_batch = query_ctx.final_res_batch
 
     async def _flash_late_interaction_encode_docs(self, ctx: ScoringServeContext):
         assert ctx.n_queries is not None

vllm/entrypoints/pooling/scoring/utils.py

@@ -25,6 +25,37 @@ from .typing import (
 )
 
 
+def get_num_special_tokens_for_pair(tokenizer) -> int:
+    """Get number of special tokens added for a text pair encoding."""
+    method = getattr(tokenizer, "num_special_tokens_to_add", None)
+    if method is not None:
+        try:
+            return method(pair=True)
+        except TypeError:
+            pass
+    # Fallback: compute by tokenizing empty strings
+    empty_encoding = tokenizer("", text_pair="", add_special_tokens=True)
+    return len(empty_encoding["input_ids"])
+
+
+def truncate_text_to_tokens(
+    text: str,
+    tokenizer,
+    max_tokens: int,
+) -> str:
+    """Truncate text to a maximum number of content tokens.
+
+    Uses offset_mapping to slice the original text at the exact character
+    boundary, avoiding lossy encode→decode round-trips that can shift
+    the token count by 1-3 tokens due to BPE merge boundary changes.
+    """
+    encoding = tokenizer(text, add_special_tokens=False, return_offsets_mapping=True)
+    if len(encoding["input_ids"]) <= max_tokens:
+        return text
+    char_end = encoding["offset_mapping"][max_tokens - 1][1]
+    return text[:char_end]
+
+
 def compute_maxsim_score(q_emb: torch.Tensor, d_emb: torch.Tensor) -> torch.Tensor:
     """
     Compute ColBERT MaxSim score.

vllm/entrypoints/pooling/typing.py

@@ -89,6 +89,9 @@ class PoolingServeContext(Generic[PoolingRequestT]):
     ## for IOProcessorResponse
     response: Any | None = None
 
+    ## for flash-late-interaction
+    query_final_res_batch: list[PoolingRequestOutput] | None = None
+
 
 @dataclass
 class OfflineInputsContext: