OpenShelf

简体中文 · Codex plugin · Claude Code plugin · Quick start · Concepts · Search and evidence · Tool reference

OpenShelf is a local-first MCP server for building searchable knowledge bases from local folders. It indexes text-layer PDFs into DuckDB, exposes evidence-grounded retrieval tools to agents, and separates corpus-backed answers from answers that require additional reasoning.

OpenShelf is designed for research papers, textbooks, technical documents, and local document libraries. It does not require a cloud vector database by default, does not upload source files, and keeps generated DuckDB files, PDF caches, and rendered page images out of the repository.

Why OpenShelf

Many RAG tools blur the line between "retrieved related text" and "the corpus supports this answer." OpenShelf keeps that boundary explicit:

• Build reusable DuckDB knowledge bases from local files.

• Use explainable DuckDB-backed BM25 text retrieval by default.

• Preserve page chunks, technical-result chunks, and source-page evidence.

• Distinguish closed corpus and open research corpus boundaries.

• Label results as supported, related_only, or not_found.

• Share a knowledge base directly by sharing its .duckdb file.

Related MCP server: Hoard

Features

Quick Start

npm install
npm run openshelf-mcp

Add the server to your Codex MCP config:

[mcp_servers.openshelf]
command = "npm"
args = ["--prefix", "/path/to/OpenShelf", "run", "--silent", "openshelf-mcp"]

Add a searchable PDF:

npm run create-document -- '{"pdf_path":"<path-to-book.pdf>","title":"Book Title","authors":["Author"],"tags":["book"]}'

See Quick start for the full flow.

Codex Plugin

This repository is also a Codex plugin root. It contains:

.codex-plugin/plugin.json  plugin manifest
.mcp.json                  OpenShelf MCP server config
skills/openshelf/          agent guidance for using OpenShelf
.agents/plugins/           local marketplace config

Local installation:

codex plugin marketplace add /path/to/OpenShelf
codex plugin add openshelf@openshelf-local

Start a new Codex thread after installation so Codex loads the OpenShelf MCP tools from the plugin.

In plugin mode, OpenShelf stores knowledge-base data under ~/.openshelf/data by default, not inside the Codex plugin cache. Existing .duckdb files can be registered into that catalog with create_db_from_exist.

Claude Code Plugin

This repository also supports the Claude Code plugin layout:

.claude-plugin/plugin.json       Claude Code plugin manifest
.claude-plugin/marketplace.json  Claude Code local marketplace
.mcp.json                        OpenShelf MCP server loaded by Claude Code

Local installation:

claude plugin marketplace add /path/to/OpenShelf
claude plugin install openshelf@openshelf-local

Restart Claude Code or start a new session after installation. Claude Code imports the MCP server named openshelf. Plugin data is stored under Claude's ${CLAUDE_PLUGIN_DATA}/data by default; existing .duckdb files can be registered with create_db_from_exist.

Recommended Workflow

OpenShelf is designed for an LLM agent with MCP tools, not for users to manually execute every retrieval step. A typical flow is:

1. The user names a knowledge base and asks a question in natural language, such as "Use research_corpus to answer this."

2. The agent chooses search, search_terms, or search_technical_results based on the question.

3. If the result is supported, the agent answers directly from cited evidence.

4. If the result is related_only or not_found, the agent explains that corpus evidence is insufficient and asks whether the user allows further reasoning.

5. If the user allows further reasoning and the corpus is closed, the agent uses check_reasonable to audit whether the reasoning exceeds the corpus boundary. If the corpus is open research, the agent may continue, but must label what comes from the knowledge base and what is independent reasoning.

6. If theorem, definition, or proposition-level retrieval is needed, the agent can suggest calling build_technical_index on already ingested documents to generate technical-result chunks.

PDF Requirements

By default, OpenShelf only accepts PDFs whose text can be extracted directly. LaTeX-generated papers and ebooks with embedded text usually work. Scanned PDFs, image-only PDFs, and PDFs whose text cannot be copied and pasted are rejected.

Default settings:

ocr: "never"
require_searchable: true

OCR must be explicitly enabled for scanned documents. It depends on local Tesseract and may be unreliable for formulas, tables, and complex layouts.

See Quick start: PDF requirements.

Core Tools

See Tool reference for complete schemas.

Documentation

Development

npm run typecheck
npm run test:unit

Runtime data stays local and is ignored by Git:

data/index/        DuckDB databases and catalog
data/pdfs/         optional PDF staging area
data/rendered/     rendered page cache
data/test_outputs/ test outputs

Next: Quick start