claude-code-system-prompts/system-prompts/data-files-api-reference-python.md

<!--
name: 'Data: Files API reference — Python'
description: Python Files API reference including file upload, listing, deletion, and usage in messages
ccVersion: 2.1.63
-->
# Files API — Python

The Files API uploads files for use in Messages API requests. Reference files via \`file_id\` in content blocks, avoiding re-uploads across multiple API calls.

**Beta:** Pass \`betas=["files-api-2025-04-14"]\` in your API calls (the SDK sets the required header automatically).

## Key Facts

- Maximum file size: 500 MB
- Total storage: 100 GB per organization
- Files persist until deleted
- File operations (upload, list, delete) are free; content used in messages is billed as input tokens
- Not available on Amazon Bedrock or Google Vertex AI

---

## Upload a File

\`\`\`python
import anthropic

client = anthropic.Anthropic()

uploaded = client.beta.files.upload(
    file=("report.pdf", open("report.pdf", "rb"), "application/pdf"),
)
print(f"File ID: {uploaded.id}")
print(f"Size: {uploaded.size_bytes} bytes")
\`\`\`

---

## Use a File in Messages

### PDF / Text Document

\`\`\`python
response = client.beta.messages.create(
    model="{{OPUS_ID}}",
    max_tokens=1024,
    messages=[{
        "role": "user",
        "content": [
            {"type": "text", "text": "Summarize the key findings in this report."},
            {
                "type": "document",
                "source": {"type": "file", "file_id": uploaded.id},
                "title": "Q4 Report",           # optional
                "citations": {"enabled": True}   # optional, enables citations
            }
        ]
    }],
    betas=["files-api-2025-04-14"],
)
print(response.content[0].text)
\`\`\`

### Image

\`\`\`python
image_file = client.beta.files.upload(
    file=("photo.png", open("photo.png", "rb"), "image/png"),
)

response = client.beta.messages.create(
    model="{{OPUS_ID}}",
    max_tokens=1024,
    messages=[{
        "role": "user",
        "content": [
            {"type": "text", "text": "What's in this image?"},
            {
                "type": "image",
                "source": {"type": "file", "file_id": image_file.id}
            }
        ]
    }],
    betas=["files-api-2025-04-14"],
)
\`\`\`

---

## Manage Files

### List Files

\`\`\`python
files = client.beta.files.list()
for f in files.data:
    print(f"{f.id}: {f.filename} ({f.size_bytes} bytes)")
\`\`\`

### Get File Metadata

\`\`\`python
file_info = client.beta.files.retrieve_metadata("file_011CNha8iCJcU1wXNR6q4V8w")
print(f"Filename: {file_info.filename}")
print(f"MIME type: {file_info.mime_type}")
\`\`\`

### Delete a File

\`\`\`python
client.beta.files.delete("file_011CNha8iCJcU1wXNR6q4V8w")
\`\`\`

### Download a File

Only files created by the code execution tool or skills can be downloaded (not user-uploaded files).

\`\`\`python
file_content = client.beta.files.download("file_011CNha8iCJcU1wXNR6q4V8w")
file_content.write_to_file("output.txt")
\`\`\`

---

## Full End-to-End Example

Upload a document once, ask multiple questions about it:

\`\`\`python
import anthropic

client = anthropic.Anthropic()

# 1. Upload once
uploaded = client.beta.files.upload(
    file=("contract.pdf", open("contract.pdf", "rb"), "application/pdf"),
)
print(f"Uploaded: {uploaded.id}")

# 2. Ask multiple questions using the same file_id
questions = [
    "What are the key terms and conditions?",
    "What is the termination clause?",
    "Summarize the payment schedule.",
]

for question in questions:
    response = client.beta.messages.create(
        model="{{OPUS_ID}}",
        max_tokens=1024,
        messages=[{
            "role": "user",
            "content": [
                {"type": "text", "text": question},
                {
                    "type": "document",
                    "source": {"type": "file", "file_id": uploaded.id}
                }
            ]
        }],
        betas=["files-api-2025-04-14"],
    )
    print(f"\\nQ: {question}")
    print(f"A: {response.content[0].text[:200]}")

# 3. Clean up when done
client.beta.files.delete(uploaded.id)
\`\`\`