> For the complete documentation index, see [llms.txt](https://docs.zaia.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zaia.app/tools/available-tools/pdf-reader-tool.md).

# PDF Reader Tool

The **PDF Reader** Tool allows an Agent to read, interpret, and reason over the **entire content of a PDF document that is uploaded during the Agent configuration**.

Unlike Knowledge Bases, which split content into chunks for retrieval, PDF Reader preserves the **full structure and continuity of a single document**, enabling deeper and more contextual reasoning.

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### 🔎 What It Does

With PDF Reader, an Agent can:

* Read a **pre-configured PDF document**
* Read **encrypted or protected PDFs** when text is still extractable
* Understand the document **as a whole**, without fragmentation
* Extract insights, summaries, rules, or structured information
* Reason across sections, pages, and references consistently

This tool is ideal when a document must be treated as **authoritative context**, not as searchable snippets.

***

### 🧠 How PDF Reader Works

PDF Reader acts as a **static cognitive extension** of the Agent.

At configuration time:

1. The Agent creator uploads a PDF file.
2. The full document is ingested as a **single contextual source**.
3. During conversations, the Agent can reason over the entire document whenever needed.
4. The document remains available to the Agent as long as the tool exists.

The Agent decides to use the PDF Reader based on the **tool description**, not by user action.

### Model compatibility

Supported models, including **Grok 4.5**, receive the configured PDF Reader information correctly when the Agent prepares a tool call.

The tool definition must remain complete in the Agent context. If the configuration is invalid or unavailable, the execution must report a clear failure instead of passing an undefined tool property.

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### 🔐 Encrypted PDFs and readability

Zaia does not reject a PDF only because it is encrypted or protected.

If the file still allows text selection or extraction, Zaia processes it normally.

When the primary extraction path returns no usable content, Zaia retries with a plain-text fallback.

Zaia only treats the file as unreadable when no text can be extracted after all supported attempts.

This reduces false negatives for protected files that still contain readable content.

#### PDFs that still fail

Zaia cannot extract content from:

* Image-only or scanned PDFs with no selectable text
* Invalid or corrupted PDF files
* PDFs that truly contain no extractable text

When extraction fails, Zaia reports that the content could not be extracted instead of assuming password protection.

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### 📚 PDF Reader vs Knowledge Base

#### Use **PDF Reader** when:

* The document must be interpreted as a whole
* Cross-section understanding is required
* The content represents a single source of truth (e.g., contract, policy, manual)
* The document does not need semantic retrieval by fragments

#### Use **Knowledge Base** when:

* Content must be searchable and modular
* Information changes frequently
* Multiple documents need to be queried
* You want long-term, scalable retrieval

💡 **Rule of thumb:**\
PDF Reader is for **deep reasoning over one document**.\
Knowledge Base is for **searching across many documents**.

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### 📄 Common Use Cases

* Company policies or internal rulebooks
* Legal contracts or compliance documents
* Technical manuals or specifications
* Institutional PDFs that must be followed strictly

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### ⚙️ Tool Configuration

When creating a PDF Reader Tool, you configure:

* **Name**\
  A clear identifier for the tool\
  Example: `Company Policy PDF`
* **Description**\
  Guides the Agent on when to use the document\
  Example:

  > “Use this tool whenever the user asks about company rules, policies, or internal procedures.”
* **PDF File**\
  The document uploaded during Agent configuration

The description is essential — it determines **when the Agent will rely on the PDF**.

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### 🧠 Best Practices

* Use PDF Reader for documents that must be interpreted in full
* Avoid duplicating large documents into the main prompt
* Keep the description explicit and scoped
* If the document needs frequent updates or search, prefer a Knowledge Base
* Combine with Tasks or Follow Ups to act on document-based conclusions

***

### ✅ Key Takeaway

The **PDF Reader** Tool allows an Agent to reason over a **single, complete PDF document configured by the Agent creator**, without chunking or fragmentation.

It is the best choice when structural integrity, coherence, and full-context understanding are critical — including protected PDFs that still expose readable text.