RAG Skill

Local Knowledge Base Retrieval Skill (kb-retriever)

Knowledge Base Directory Description

• Knowledge is stored in a root directory containing various file types (e.g., .md / .txt, .pdf, .xlsx, etc.), usually split into multi-level subdirectories by type or business purpose.
• Hierarchical Directory Index Files:
  • The root directory has a data_structure.md, explaining the main "domain directories" and their purposes.
  • Each domain directory can have its own data_structure.md, explaining the subdirectories/files within it and their respective purposes.
  • Deeper subdirectories can continue to have data_structure.md, forming a multi-level index tree.
• Knowledge Base Root Directory Conventions:
  • By default, the knowledge base is assumed to be in the knowledge/ directory under the current project root.
  • If the user explicitly specifies another path in the conversation (e.g., "My knowledge base is at /data/kb" or "Use the ./docs directory as the knowledge base"), the user-specified path is used as the root.
  • When the default path knowledge/ does not exist or fails to be accessed, confirm the actual knowledge base root directory location with the user instead of guessing.
• Individual business files may be very large:
  • Do not use Read to read the entire file directly.
  • For PDF and Excel, use the corresponding skills for structured processing first, then combine with grep / partial reading for fine-grained retrieval.

Locating the knowledge Root Directory

• Prioritize the user: If the user provides a path (e.g., ./docs, ./knowledge-personal), use it directly.
• Default root directory: Otherwise, the root directory is assumed to be knowledge/ under the current project.
  • Explicitly check if the directory exists using the shell: Prefer test -d knowledge, or failing that, ls -d knowledge.
  • Note: Prohibit using patterns like Glob "knowledge" in . to determine if a directory exists. Glob only returns file paths, not the directory itself; an empty result doesn't distinguish between "directory doesn't exist" and "directory exists but is empty".
• Only when the root directory is confirmed to exist via test -d or similar, use Glob to retrieve content within that directory and treat the directory as the path. For example:
  • Index files: pattern="**/data_structure.md", path="knowledge"
  • All Markdown: pattern="**/*.md", path="knowledge"
• If the default knowledge/ does not exist (test -d fails): Do not guess other directories. Clearly tell the user that the default root directory was not found and ask them to specify the actual knowledge base path.

Key Principle: Learn First, Process Later

Mandatory Checklist when encountering PDF or Excel files:

• ✅ Read the corresponding references document to learn processing methods.
• ✅ Understand the recommended tools and commands.
• ✅ Complete file processing (extraction/conversion).
• ⏭️ Now retrieval can begin.

Prohibited Actions:

• ❌ Attempting to process a PDF without reading pdf_reading.md.
• ❌ Attempting to process an Excel without reading excel_reading.md.
• ❌ Skipping the file processing step and retrieving directly from the original PDF/Excel.

Overall Process

1. Understand User Requirements

   • Read the user's question and extract:
     • Topic/Domain keywords (e.g., "sales report", "system architecture", "API documentation").
     • Time or scope constraints (e.g., "2023 Q1", "recent version").
     • Desired output type (explanation, summary, specific field values, etc.).
   • Determine the knowledge base root directory:
     • Check if the user specified a knowledge base path in the question first.
     • Otherwise, use the default root directory knowledge/.
     • If the default root directory doesn't exist or the structure is abnormal, ask the user for confirmation instead of making assumptions.

2. Hierarchically Review Directory Index data_structure.md

   • Use the concept of a "Current Working Directory":
     • Start from the user-specified knowledge base root directory by default; if not specified, use the current directory.
   • If data_structure.md exists in the current working directory:
     • Use Read to read the first few hundred lines (e.g., limit=300), and continue reading in segments if necessary.
     • Goal:
       • Understand what subdirectories and files are in the current directory.
       • Understand the purpose description for each subdirectory/file.
     • Based on the user's question, select the most relevant subdirectories or files as candidates.
   • For candidate subdirectories:
     • Recursively enter the subdirectory, treating it as the new "Current Working Directory", and repeat the process of searching for data_structure.md.
     • During recursion, avoid diving into all branches at once; prioritize paths most relevant to the question.
   • For candidate business files (md/text, PDF, Excel, etc.):
     • After completing the necessary directory level exploration, collect these files as the final retrieval target list.
   • When prioritizing:
     • Prioritize domain directories and files whose purpose descriptions highly match the question topic.
     • Secondly, consider constraints like time/version (if reflected in the index).
     • General documentation (like README.md, overall design documents) should have lower priority.

3. Learn File Processing Methods (Mandatory for PDF/Excel)

   • Before processing PDF files:
     • Must read references/pdf_reading.md (note this directory is under Skills, not Knowledge) to learn extraction methods.
     • Key focus: pdftotext command, pdfplumber usage, table extraction methods.
   • Before processing Excel files:
     • Must read references/excel_reading.md to learn reading methods.
     • Must read references/excel_analysis.md to learn analysis methods.
     • Key focus: pandas reading, column filtering, data filtering.
   • Purpose: Ensure correct tools and methods are used, avoiding blind retrieval.

4. Execute Processing and Retrieval by File Type

   • Use the learned methods to process files (extraction, conversion, structuring).
   • For each category of candidate files, follow the "Markdown/Text", "PDF", or "Excel" strategies below.
   • General Principles:
     • Start with the most relevant and precise files.
     • Perform progressive local retrieval within each file to avoid loading the entire content at once.
     • If the current file doesn't provide satisfactory information, switch to the next candidate file.

5. Iterative Retrieval

   • All file types use a unified "Multi-round Iterative Retrieval Mechanism" (see Common Retrieval Principles above).

6. Answer Organization and Sourcing

   • Consolidate the context obtained from multiple rounds of retrieval to answer the user's question comprehensively.
   • Aim to:
     • Provide clear and direct answers.
     • Indicate the filenames used (including approximate locations like sections or line/page numbers where necessary).
   • If the answer is based on inference or incomplete information:
     • Clearly mark assumptions and uncertainties.
     • Prompt the user to provide a more specific file scope or keywords.

Common Retrieval Principles

Keyword Selection Strategy

• Extract 3-8 keywords from the user's question (including possible English abbreviations, synonyms, hypernyms/hyponyms).
• Use combinable phrases (e.g., "sales report", "API interface timeout").
• Include business terms, technical jargon, and common abbreviations (e.g., "uv", "pv", "GMV") as necessary.

grep Retrieval Basic Principles

• Always specify the most precise include and path possible, avoiding searching the entire directory.
• Prioritize core nouns and terms from the question in the pattern, then try synonyms.
• For each hit, only read the local area around the match (a few lines above and below).
• Save "Filename + Position Information + Text Snippet".

Multi-round Iterative Retrieval Mechanism (Max 5 times)

A unified iterative strategy for all file types:

1. Iteration Control
   • Maintain an "Attempted Retrieval Count", max 5 times.
   • Increment the count after each retrieval.
2. Each Round Workflow
   1. Generate/update retrieval keywords based on the question (can include synonyms, extensions).
   2. Select files or file parts that haven't been fully retrieved yet.
   3. Execute retrieval (grep / partial read / specialized Skill call).
   4. Analyze the obtained context snippets.
   5. Determine if it's enough to answer the question.
3. Termination Conditions
   • Found enough context to support the answer; OR
   • Reached 5 attempts without finding suitable information.
4. Handling Insufficient Information
   • Clearly inform the user if information is missing or might not be in the current knowledge base.
   • Provide the closest information found and explain the uncertainty.
   • Suggest how the user can narrow the scope (more specific filenames, keywords, time range, etc.).

Important Notes

• Prohibit calling Glob "knowledge" in . or any attempt to use Glob to determine directory existence for the first time. Directory existence should be checked via shell commands (e.g., test -d).
• When using this Skill to query the knowledge base, prohibit using other tools like web search to obtain knowledge.

Specific Strategies for Different File Types

1. Markdown / Text Files (.md, .txt, .log, etc.)

1. Candidate File Selection

   • Judge relevance based on data_structure.md, filenames, and paths.
   • Prioritize retrieving title and index files (e.g., summary documents, design overviews).

2. grep Positioning and Partial Reading

   • Use the Grep tool on specified candidate files, limiting include to specific suffixes (e.g., "*.md").
   • For files with matches, use Read to only read the local area around the match:
     • Control reading via line number offset and limit (e.g., read a few dozen lines before and after the matching line).
     • Avoid reading the entire file.

3. Special Handling

   • If the content is just a table of contents/title, continue to locate deeper content based on links or section names.
   • Apply the "Multi-round Iterative Retrieval Mechanism" (see Common Retrieval Principles above).

2. PDF File Retrieval Strategy

Workflow:

1. First: Read Processing Guide

   • Before processing any PDF, must read references/pdf_reading.md (note this directory is under Skills, not Knowledge).
   • Key focus: pdftotext command, pdfplumber usage, table extraction methods, Quick Decision Table.

2. Select Candidate PDFs

   • Based on the description in data_structure.md, select the 1-3 most relevant files.
   • If the user specifies a particular PDF file, prioritize that file.

3. Apply Learned Methods to Extract Text

   • Use tools recommended in pdf_reading.md (prefer pdftotext or pdfplumber).
   • IMPORTANT: Use pdftotext input.pdf output.txt to extract text to a file; do not output directly to stdout (to avoid consuming many tokens).
   • If tables need to be extracted, use pdfplumber's table extraction functionality.

4. Execute Retrieval on Extraction Results

   • Use grep to perform keyword searches on the extracted text.
   • For each hit, extract the context around the match (dozens of lines above/below or adjacent pages).
   • Save "Filename + Page Number/Approximate Position + Text Snippet".
   • Apply the "Multi-round Iterative Retrieval Mechanism" (see Common Retrieval Principles above).

3. Excel File Retrieval Strategy

Workflow:

1. First: Read Processing Guide

   • Before processing any Excel, must read:
     • references/excel_reading.md - Learn how to read worksheets (note this directory is under Skills, not Knowledge).
     • references/excel_analysis.md - Learn how to analyze data (note this directory is under Skills, not Knowledge).
   • Key focus: pandas reading methods, column filtering, data filtering, aggregation operations.

2. Select Candidate Excels

   • Based on data_structure.md and file/worksheet names, select the most relevant sheets.
   • Prioritize workbooks/sheets containing keywords like "report", "statistics", "log", "config", "mapping", etc.
   • If the user specifies a particular Excel file, prioritize that file.

3. Apply Learned Methods to Explore Structure

   • Use pandas to read the first 10-50 rows (using the nrows parameter).
   • Key mastery: Column/field names, data types (numeric, date, text), key fields.
   • Compare column names with the user's question to identify potential key fields (e.g., "revenue", "sales", "error_code", etc.).

4. Execute Data Retrieval and Analysis

   • Use learned pandas methods for filtering and aggregation (e.g., df[df['column'] == value]).
   • Read only the data around the matching rows at a time, avoiding reading the entire sheet at once.
   • If the question includes a time range, add time filtering to the retrieval.
   • Apply the "Multi-round Iterative Retrieval Mechanism" (see Common Retrieval Principles above).

Synergy with Other Tools

PDF Processing

• Must read references/pdf_reading.md before processing PDF to learn methods.
• Use pdfplumber / pypdf for text extraction, table extraction, and metadata reading.
• Prioritize using the pdftotext command-line tool for fast text extraction.

Excel Processing

• Must read before processing Excel:
  • references/excel_reading.md - Learn reading methods.
  • references/excel_analysis.md - Learn analysis methods.
• Use pandas for data exploration, previewing, filtering, and analysis.

Tool Usage Principles

• Grep: Used to find line numbers and matching snippets by keyword in specified files; always specify the most precise include and path possible.
• Read: Only used for partial file reading; always set a reasonable limit (e.g., 200-500 lines) and appropriate offset.
• For any file that may be large:
  • Prohibit reading directly from beginning to end.
  • Always narrow the range via indexes, table of contents, or keywords before reading.

Answer Style and Error Handling

• Answer Style
  • Try to answer in the language the user asked (Chinese/English).
  • Give the conclusion first, then the brief rationale.
  • If needed, list the files cited and their approximate locations at the end, for example:
    • Source: design/api_gateway.md near line 100
    • Source: reports/2023_Q1_sales.xlsx Summary worksheet
• Missing or Uncertain Information
  • Clearly state if no exact match was found in the current knowledge base or if only a partial answer can be given.
  • Do not fabricate facts.
  • Suggest how the user can help narrow the scope:
    • Specify a more specific directory/file.
    • Provide more precise keywords or field names.
    • Specify a time/version range.