Anthropic's top of the range, and priced like it. If Opus 5 already passes your evals you're paying double for nothing.
Status
released
Released
1 September 2026
Context
1M tokens
Price / 1M
$10.00 in, $50.00 out
Mentions
3
Threads
38
What is Claude Fable 5.1?
Claude Fable 5.1 is a model from Anthropic, built in the US. It's out, and you can call it today.
When did Claude Fable 5.1 come out?
Anthropic released it on 1 September 2026. That date comes from the lab's own docs.
The tracker first logged the name on 1 September 2026 and last saw it on 3 September 2026.
What does it cost, and how much context does it hold?
Lab
Anthropic
Built in
US
Status
released
API model id
claude-fable-5-1
Released
1 September 2026
Context window
1M tokens
Max output
128K tokens
Input, per 1M tokens
$10.00
Output, per 1M tokens
$50.00
List prices per million tokens, read off the lab's own docs. Caching, batching and volume deals all cut the real number, so treat this as the ceiling. Check the source before you budget against it.
A dash means the lab hasn't published that number for that model.
What are people discussing about Claude Fable 5.1?
We tracked 38 public discussions naming Claude Fable 5.1 across r/ClaudeAI, r/ClaudeCode, r/GeminiAI and r/OpenAI and 2 other communities between 27 August 2026 and 4 September 2026.
The subject that came up most was availability and outages, then benchmark results. A discussion can cover several, so these add up to more than 38.
What people are discussing
Threads
availability and outages
8
benchmark results
3
what it costs
2
refusals and safety behaviour
2
using it to write code
1
Every mention we've logged
Every tracked post, release, changelog entry or incident whose title or summary names Claude Fable 5.1. Newest first, each one linking to where the lab published it.
Sep 3 , 16:23 UTC
Resolved - The issue affecting Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 has been resolved. Impact has ended as of 9:16 PT / 16:16 UTC.
Sep 3 , 16:06 UTC
Monitoring - A fix has been deployed for Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and we are monitoring for recovery.
Sep 3 , 15:25 UTC
Update - The only affected models right now are Opus 4.8 and Opus 5. The rest of the models have recovered to baseline error rate.
Sep 3 , 14:49 UTC
Update - We are continuing to work on a fix for this issue.
Sep 3 , 13:50 UTC
Update - An exhaustive list of…
What's changed
Added Claude Fable 5.1 ( claude-fable-5-1 ), now the default Fable model — 1M context, $10/$50 per Mtok with $0.25/Mtok cache reads
Added "Time format" ( timeFormat ) and timeZone settings: 12-hour, 24-hour, 24-hour UTC, or a strftime pattern for the turn-end clock and transcript-view timestamps
Added a Containment Escape rule to auto mode so cloud metadata-credential fetches, egress evasion, and cross-tenant reach are no longer auto-approved unless your environment marks them expected
Added CLAUDE_CODE_SUBAGENT_MODEL_FORCE to apply CLAUDE_CODE_SUBAGENT_MODEL (or the main…
Added Claude Fable 5.1 (claude-fable-5-1), now the default Fable model — 1M context, $10/$50 per Mtok with $0.25/Mtok cache reads
Added "Time format" (timeFormat) and timeZone settings: 12-hour, 24-hour, 24-hour UTC, or a strftime pattern for the turn-end clock and transcript-view timestamps
Added a Containment Escape rule to auto mode so cloud metadata-credential fetches, egress evasion, and cross-tenant reach are no longer auto-approved unless your environment marks them expected
Added CLAUDE_CODE_SUBAGENT_MODEL_FORCE to apply CLAUDE_CODE_SUBAGENT_MODEL (or the main model) to every…
Keep reading
The release timeline is every model we know about, filterable by lab, country and date. The tracker is the live feed these mentions come from, and Model Watch is the whole catalogue on one page.