The Ultravox corpus service is the easiest way to add RAG to your agents. All of the relevant APIs appear under /api/corpora (note: ‘corpora’ is the plural of ‘corpus’).

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Corpus Overview

Each Corpus can contain one or more sources. Each Source contributes one or more documents, which are single files (HTML page, PDF, DOC, etc.). Each Document is broken up into one or more chunks, which are the units that may be returned for a query. For each Chunk several vectors are produced for similarity search. The API exposes metadata about documents as well as the number of chunks and vectors in a corpus. However, there are no APIs provided to directly manipulate or edit documents, chunks, or vectors. If you need to update or delete documents, you must update or delete the source.

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Providing Corpus Access to Agents

Keep API Keys Safe
Using the Query Corpus endpoint directly from your agents could expose your Ultravox API key. Use the queryCorpus tool instead.
We provide the built-in queryCorpus tool that should be used by your agents. For example, if we wanted to create a voice agent to answer questions about Seattle, we could provide the tool like this: 
{
  "systemPrompt": "Use the queryCorpus tool to answer questions about Seattle.",
  "selectedTools": [
    {
      "toolName": "queryCorpus", 
      "parameterOverrides": {
        "corpus_id": "<your_corpus_id_here>",
        "max_results": 5
      }
    }
  ]
}

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queryCorpus Tool Performance

  • Maximum of 20 chunks per query
    • By default, the model may dynamically choose a value between 1-20, defaulting to 5. A static value may be provided via override.
    • Query response latency is not significantly impacted by the number of chunks returned.
    • More chunks returned will grow the overall agent context, which will mean slower subsequent generations.
    • More chunks may also confuse the agent if most chunks are irrelevant.

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Limits and Configuration

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Overall Limits

The system has the following limits:
  • 20 sources (max) per corpus
  • 200 documents (max) per source
  • 10MB (max) document size for file uploads

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Account Limits

  • Default limit is 2 corpora per account
  • Paid plans have higher limits on corpora

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Document Management

  • Documents can be viewed but not edited directly
  • To update documents, create a new source
  • Supported document types:
    • Text files (including Markdown)
    • PDFs
    • Word documents
    • EPUB files
    • PowerPoint presentations
    Note: If there are additional content types you need, please let us know.

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Source Management

  • PATCH requests on a source triggers a refresh/recrawl while maintaining the ID and created timestamp
  • The corpus is still queryable during a recrawl but might return inconsistent (i.e. outdated) resources until the recrawl is finished
  • Provided urls via startUrls will trigger crawling on anything in the same domain (subdomains must be specified separately)

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Deletion Behavior

  • Deleting a corpus cascades to remove all associated:
    • Sources
    • Documents
    • Chunks
    • Vectors
  • Deleted corpora cannot be queried
  • Deleting a source cascades to remove all associated documents, chunks, and vectors