Claude Fable 5.1
claude-fable-5-1Run Claude Fable 5.1 in a hosted Python Task with structured output, web search, extended thinking, file inputs and MCP connectors.
Anthropic's most capable publicly available model, built for ambitious long-running agentic work in software engineering, scientific research, and complex knowledge work. Improves on Fable 5 in coding and root-cause debugging, and cuts cache read pricing by 75% to $0.25 per million tokens. Features mandatory adaptive thinking, 1M token context window, 128K output capacity, and all effort levels including xhigh and max. Priced at $10/$50 per million tokens. Knowledge cutoff June 2026.
What Claude Fable 5.1 supports in qbash
- Structured outputReplies as JSON that matches a schema you pass.
- MCP connectorsCalls tools on MCP connectors during a request.
- Web searchSearches the web while it answers.
- Extended thinkingReasons through a problem before it replies.
- Reasoning effort5 levels, from low to max.
- Image inputReads WEBP, PNG, JPEG and GIF images.
- Document inputReads PDF, TEXT, DOC, XLS, RTF and 7 more files.
- Prompt cachingRepeated input is billed at the cached rate.
What is qbash?
qbash is where you build Tasks: Python programs that run a business process on managed infrastructure. Your code runs the steps and calls a model like Claude Fable 5.1 only at the ones that need judgment, with integrations, memory and files available in the same script.
A developer writes the Task once, and anyone on the team runs it from a form, on a schedule, from a webhook or from chat. Each Task is versioned and every run is logged.
Specifications
- Context window
- 1Mtokens
- Max output
- 128,000tokens
Structured output with Claude Fable 5.1 in a Python Task
qbash.ai.raw calls Claude Fable 5.1 from a Task. Pass a JSON Schema as output_schema and the reply comes back as a Python dict that matches it, ready to route to a connector.
ticket = qbash.inputs.get("ticket")
triage = qbash.ai.raw(
f"Summarize this support ticket and rate its urgency:\n\n{ticket}",
model="claude-fable-5-1",
output_schema={
"type": "object",
"properties": {
"summary": {"type": "string"},
"urgency": {"type": "string", "enum": ["low", "medium", "high"]},
},
"required": ["summary", "urgency"],
},
)
# triage is a dict, e.g. {"summary": "...", "urgency": "high"}
if triage["urgency"] == "high":
qbash.integrations.slack.create_message(
channel="#support",
text=triage["summary"],
)
qbash.output(triage)
Connect Claude Fable 5.1 to MCP servers
In qbash chat and a Task's inline prompts, you can attach MCP connectors to Claude Fable 5.1. It calls their tools during the request, for example to read a Postgres table or post to a Slack channel.
This is MCP on the model side. Adding MCP servers to Claude Code or Claude Desktop is a separate setup, and qbash can publish your Tasks as an MCP server for those clients as well.
Use Claude Fable 5.1 with web search
Turn on Web Search in an inline prompt's model bar and Claude Fable 5.1 searches the web while it answers. Searches are billed at $10.00 per 1,000.
Reasoning effort with Claude Fable 5.1
Set Effort to low, medium, high, xhigh and max in the prompt's Settings. The default is high. Higher effort spends more tokens on reasoning before the reply.
Turn on Thinking in the same Settings popover to have Claude Fable 5.1 reason through a problem before it replies.
Claude Fable 5.1 pricing
| Input | $10.00 per 1M tokens |
|---|---|
| Output | $50.00 per 1M tokens |
| Cache read | $0.25 per 1M tokens |
| Cache write, 5 minutes | $12.50 per 1M tokens |
| Cache write, 1 hour | $20.00 per 1M tokens |
| Web search | $10.00 per 1K searches |
Standard rates in USD.
Supported file formats
Images
- WEBP up to 5 MB
- PNG up to 5 MB
- JPEG up to 5 MB
- GIF up to 5 MB
Documents
- TEXT
- DOC
- XLS
- RTF
- DOCX
- XLSX
- PPTX
- PPT
- ODT
- ODP
- ODS
Anthropic retains data from Claude Fable 5.1 for a minimum of 30 days. Zero Data Retention is not available for this model. Anthropic Privacy Policy