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chunktuner

PyPI version Python versions License: MIT CI Docs

用于 RAG 流水线的自动分块调优器和 MCP 服务器。

提供您的文档,它会尝试多种分块策略,衡量哪种策略能让 AI 最准确地回答问题,并告诉您胜出者。

chunktuner 项目流程:文档经过策略、评估,最终得到推荐配置


功能概述

在构建 RAG 流水线时,如何将文档拆分为块直接影响检索质量。chunktuner 自动化了为您的特定语料库、嵌入模型和用例寻找最佳分块策略的过程。

它会对固定标记窗口、递归字符拆分、语义拆分、PDF 结构化分块和基于 AST 的代码分块等策略进行基准测试,然后根据实际检索指标(标记召回率、MRR、NDCG)和可选的生成指标(RAGAS 忠实度、答案相关性)对每种策略进行评分。


Related MCP server: golden-dataset-mcp

接口

  • Python 库 — 以编程方式集成到您的流水线中

  • CLI (chunk-tune) — 从终端进行人工驱动的调优

  • MCP 服务器 — 直接从 Claude Desktop 或任何 MCP 主机使用


快速入门

# Install
uv tool install chunktuner

# Initialize workspace
chunk-tune init --provider openai

# See cost estimate before running anything
chunk-tune estimate ./my_docs --use-case rag_qa

# Get a recommendation
chunk-tune recommend ./my_docs --use-case rag_qa

Python API:

from pathlib import Path
from chunktuner import FileIngestor, LiteLLMEmbeddingFunction, AutoTuner
from chunktuner import default_registry, Evaluator, ScoreCalculator

docs = FileIngestor().ingest_dir(Path("./my_docs"))
embedding_fn = LiteLLMEmbeddingFunction("text-embedding-3-small")
tuner = AutoTuner(
    strategies=default_registry,
    evaluator=Evaluator(embedding_fn),
    scorer=ScoreCalculator(use_case="rag_qa"),
)
result = tuner.recommend(docs, use_case="rag_qa")
print(result.best.config)

支持的策略

策略

最适合

fixed_tokens

基准;统一标记窗口

recursive_character

一般散文和文档

semantic

主题性强的文章

markdown_semantic

结构化 Markdown 文档

pdf_structural

带有布局区域和表格的 PDF

structural_semantic

混合布局和文本的 PDF/DOCX

late_chunking

带有密集交叉引用的长文档

agentic

高价值叙事文档

code_ast

代码仓库(Python, JavaScript)

code_window

代码基准(滑动窗口)


MCP 服务器 (Claude Desktop)

Python FastMCP (chunk-tune-mcp, stdio)。无需 Node.js 构建。请参阅 docs/mcp_setup.md。

添加到您的 .mcp.json 中:

{
  "mcpServers": {
    "chunktuner": {
      "command": "uvx",
      "args": ["--from", "chunktuner[mcp]", "chunk-tune-mcp"],
      "env": {
        "CHUNK_TUNER_BASE_DIR": "/path/to/your/corpus"
      }
    }
  }
}

可用工具:list_strategies, preview_chunks, evaluate_chunking, recommend_config。


CLI 参考

chunk-tune init       Bootstrap workspace config
chunk-tune analyze    Quick structural scan (no API cost)
chunk-tune estimate   Dry-run cost/token estimate
chunk-tune evaluate   Full evaluation across strategies
chunk-tune recommend  Evaluation + best config recommendation
chunk-tune compare    Side-by-side comparison of specific strategies
chunk-tune preview    Inspect how a strategy splits a document
chunk-tune cache      Manage embedding and chunk cache

安装选项

uv add chunktuner                    # library
uv tool install chunktuner           # global CLI
uvx chunktuner                       # ephemeral, no install

# With optional extras
uv add "chunktuner[docling]"         # PDF/DOCX support
uv add "chunktuner[ragas]"           # generation metrics
uv add "chunktuner[semantic]"        # semantic chunking
uv add "chunktuner[code]"            # AST code chunking
uv add "chunktuner[all]"             # everything

贡献

请参阅 CONTRIBUTING.md。


👨🏻💻 作者

Shantanu Deshmukh

全栈开发人员,拥有构建端到端 AI 应用的经验。

Linkedin / Twitter / AngelList

Available Tools

4 tools
evaluate_chunkingB

Dry-run cost estimate or full evaluation (DummyEmbeddingFunction if no model).

ParametersJSON Schema
NameRequiredDescriptionDefault
pathYes
top_kNo
dry_runNo
max_docsNo
use_caseNorag_qa
strategiesNo
content_typeNo
embedding_modelNo

TDQS

B3.2/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the burden. It discloses the use of a DummyEmbeddingFunction when no model is given, which is a key behavior. However, it does not mention whether the tool is read-only, side effects, or other important traits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence, concise and front-loaded. It could be more structured (e.g., listing modes separately), but it is not unnecessarily verbose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 8 parameters, no output schema, and no parameter descriptions, the description is far too minimal. It fails to explain return values, how results are presented, or how parameters interrelate, making it incomplete for effective use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters1/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%—all 8 parameters have only titles. The description adds no explanation of any parameter, leaving their meaning entirely to the schema with no additional context.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool can perform a dry-run cost estimate or a full evaluation, and mentions using a DummyEmbeddingFunction if no model is provided. This differentiates it from siblings like list_strategies and preview_chunks.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies when to use each mode (dry_run vs full evaluation), but provides no explicit guidance on when to choose this tool over its siblings. No exclusions or alternatives are mentioned.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

list_strategiesB

List registered chunking strategies, optionally filtered by content type.

ParametersJSON Schema
NameRequiredDescriptionDefault
content_typeNo

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

B3.2/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It does not state that the tool is read-only (safe), nor does it mention any side effects, authentication requirements, or rate limits. The agent can infer that listing is non-destructive, but this is not explicit.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, well-structured sentence of 10 words. It is front-loaded with the action and resource, and every word contributes meaning. There is no fluff or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simplicity of the tool (one optional parameter, output schema exists), the description provides the essential functionality. However, it lacks context about what 'chunking strategies' are and how they are registered. For a standalone tool, this might be insufficient without additional documentation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description adds minimal value beyond the input schema. It merely paraphrases 'optionally filtered by content type', which mirrors the schema property. Since schema description coverage is 0%, the description should compensate with more detail (e.g., allowed values, behavior when null), but it does not.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('List'), the resource ('registered chunking strategies'), and includes a filtering condition ('optionally filtered by content type'). It effectively differentiates from sibling tools like evaluate_chunking, preview_chunks, and recommend_config by focusing on listing rather than evaluation, preview, or recommendation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no explicit guidance on when to use this tool versus its siblings. There are no 'when-to-use' or 'when-not-to-use' statements, and no mention of alternatives. The agent is left to infer usage context from the tool name alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

preview_chunksC

Chunk inline text with one strategy + params (no embeddings).

ParametersJSON Schema
NameRequiredDescriptionDefault
textYes
configNo
strategy_nameYes

Output Schema

ParametersJSON Schema
NameRequiredDescription
resultYes

TDQS

C2.7/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description must bear the full burden. It implies no embeddings and inline processing, but does not explicitly state that no data is persisted or that the operation is idempotent. The output schema exists but behavioral side effects are not addressed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence, very concise. However, it sacrifices useful details that could be added without becoming verbose, such as examples or config structure.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given three parameters, zero schema descriptions, and a sibling set, the description is insufficient. While the output schema covers return values, the lack of parameter guidance and usage context makes it incomplete for an AI agent to use correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%. The description only hints that 'strategy_name' selects a strategy and 'config' holds parameters, but does not explain the format or constraints for 'config' (anyOf object/null). No enum values or examples are provided.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('chunk'), the resource ('inline text'), and includes a distinguishing detail ('no embeddings'). However, it could better differentiate from sibling tool 'evaluate_chunking' which likely involves evaluation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is given on when to use this tool versus siblings like 'evaluate_chunking', 'list_strategies', or 'recommend_config'. The description does not specify prerequisites or contexts.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

recommend_configC

Run tuner and return ranked Recommendation (uses dummy embeddings by default).

ParametersJSON Schema
NameRequiredDescriptionDefault
pathYes
top_kNo
max_docsNo
use_caseNorag_qa
strategiesNo
content_typeNo
embedding_modelNo

TDQS

C2.1/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description must carry the full burden. It discloses the use of dummy embeddings by default, but does not mention side effects, idempotency, or other behavioral traits like whether it modifies state or runs asynchronously.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness3/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise at one sentence, but at the cost of missing critical information. It is structured well enough for a simple statement, but could be expanded to include essential details without becoming verbose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness1/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 7 parameters, no output schema, and no annotations, the description is severely incomplete. An agent cannot determine what the tool returns, how to set parameters correctly, or what the expected behavior is beyond a vague 'tuner' operation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters1/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 0% schema description coverage, the description should explain parameters. It does not mention path, top_k, max_docs, use_case, strategies, content_type, or embedding_model, leaving all semantics to be inferred from parameter names alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose3/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description says 'Run tuner and return ranked Recommendation', which vaguely states a tuning action but does not define what a 'tuner' or 'Recommendation' is in this context. The phrase 'uses dummy embeddings by default' adds some specificity but the core purpose remains unclear.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No explicit guidance on when to use this tool versus its siblings (evaluate_chunking, list_strategies, preview_chunks). The description does not mention alternatives or conditions for use, leaving the agent to infer.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

  1. 4 tool updatesv0.1.1
    • First observedevaluate_chunking
    • First observedlist_strategies
    • First observedpreview_chunks
    • First observedrecommend_config

TDQS

B3.2/5.0

Scored across 4 tools

Disambiguation5/5

Each tool has a distinct purpose: evaluating, listing, previewing, and recommending. No overlap in functionality.

Naming Consistency5/5

All tools follow a consistent verb_noun pattern (evaluate_chunking, list_strategies, preview_chunks, recommend_config).

Tool Count5/5

Four tools is appropriate for a chunking tuner server, covering the core workflow without being too sparse or overwhelming.

Completeness4/5

The set covers listing, previewing, evaluating, and recommending chunking configurations. A minor gap is the lack of explicit strategy management, but it may be predefined.

Maintenance

ActivityInactive
ResponsivenessNo issues

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