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The Frontier Brief
Release alert
Not released · release date not announced · checked Nov 5, 2026

Fable 5.5

Is Fable 5.5 out? No. Anthropic has not announced Fable 5.5. The newest Fable is still Fable 5.1, released September 1, 2026.

Claims tracked
42
Leaked dates that passed
7
Works claiming Fable 5.5
79
Email me when it shipsSee every claim
Rows
42
Official
5
Author claims · unverified
29
Our checks
8

23 leaks · 3 reports · 2 listings · 1 benchmark claim · 5 official items · 8 checks of ours. Official means Anthropic’s own pages; everything else is somebody’s claim until Anthropic publishes it. Dates of X posts are read from the post IDs.

Before launch · 42 rows · newest first

Every claim about Fable 5.5, with its source

  • Verified confirmed by Anthropic or another primary source
  • Predicted a claim nobody has confirmed
  • Retracted appeared, then was pulled
  • author claim · unverified every row that is not Anthropic’s own page or our own check
  1. Our checkStill no announcementVerifiedour check

    At 16:45 UTC on November 5: the newsroom’s latest item is still October 28; the model directory lists Fable 5.1, Opus 5.5, Sonnet 5.5 and Haiku 5.5; the API release notes through November 5 add no model (the newest entry is an IP allowlist for the Console); the pricing page names no Fable 5.5. anthropic.com/claude-fable-5-5 returns 404 and the docs address for a fable-5-5 model shows “Page not found”.

    By The Frontier Brief · Anthropic model directory ↗ · Second source ↗

  2. Our checkStill no announcementVerifiedour check

    At 14:56 UTC on November 4: the newsroom’s latest item is October 28; the model directory still lists Fable 5.1, Opus 5.5, Sonnet 5.5 and Haiku 5.5; the API release notes through November 3 add no model; the pricing page and the Mythos and Fable pages name only 5.1. anthropic.com/claude-fable-5-5 returns 404 and the docs address for a fable-5-5 model shows “Page not found”. OpenRouter, LiteLLM’s price list and Google Cloud’s Claude page have no Fable 5.5.

    By The Frontier Brief · Anthropic model directory ↗ · Second source ↗

  3. Our checkOur check: the Fable 5.5 entry “still on Azure” is MLflow’s copy from October 14, not a new listingVerifiedour check

    On November 1 @chetaslua pointed to MLflow’s Azure model list as proof that Fable 5.5 “already hit Azure”. MLflow’s catalog bot added claude-fable-5-5 there on October 14 at 01:11 UTC (pull request 26724), while LiteLLM still listed it, with the same $10 / $50 and 1M context; nobody has removed it since. It repeats the October 13 trace. Nothing shows Azure listing the model again.

    By The Frontier Brief · MLflow commit adding the entry ↗ · Second source ↗

  4. Leak@chetaslua: a short video “one-shotted” in pure code by Fable 5.5Predictedauthor claim · unverified

    About 1.6 million views when we read it. Before it, @Hesamation posted SVGs as Fable 5.5 output on October 31 and @chetaslua a one-shot web page on November 1; @kimmonismus calls the video “most likely the latest Fable 5.5 checkpoint”. The check the post offers is a question only a model with newer knowledge can answer: that shows a newer model answered, not which one. Outputs, not a release.

    By @chetaslua; @Hesamation (October 31); @kimmonismus (relay) · Post on X ↗ · Second source ↗ · unresolved

  5. ReportTestingCatalog: Mythos 5.5 “could come next week”; Fable 5.5 arriving with it is marked as speculationPredictedauthor claim · unverified

    Written the day of the hidden-name find. It also relays reports that updated Fable 5.5 checkpoints are being A/B tested with selected users, with no public benchmark. The week runs to November 8; open at our November 4 check.

    By TestingCatalog · TestingCatalog, November 1 ↗ · Second source ↗ · unresolved

  6. Listing“Claude Mythos 5.5” turns up in the hidden HTML of Anthropic’s Mythos page, then is removedRetractedauthor claim · unverified

    First posted at 15:24 UTC: the name sat in a hidden heading and the logo’s alt text while the visible page still said Mythos 5.1. @AiBattle_ says an October 23 snapshot did not have it; by 18:40 UTC @pankajkumar_dev reported it gone. It names Mythos, not Fable. Fable 5.1 and Mythos 5.1 were announced together on September 1, so many read this as a sign Fable 5.5 is close; that link is a guess. Our November 4 check of anthropic.com/claude/mythos and /claude/fable finds only 5.1.

    By @kimmonismus (anonymous tip); TestingCatalog; @chetaslua; removal reported by @pankajkumar_dev · TestingCatalog, November 1 ↗ · Second source ↗

  7. Leak@chetaslua: Tuesday “can be launch day”, because Mythos 5.5 showed up in the site’s codePredicted · date passedauthor claim · unverified

    That was Tuesday, November 3. It passed with no announcement: the newsroom’s latest item is still October 28, and the API release notes for November 2–3 cover message threads and watermarking only. The same post hopes for a price 20% below the previous generation; a wish, not a report.

    By @chetaslua · Post on X ↗ · date passed

  8. Our checkStill no announcementVerifiedour check

    Anthropic’s newsroom (latest item October 28), the model directory (Fable 5.1, Opus 5.5, Sonnet 5.5, Haiku 5.5) and the API release notes through October 30 mention no new Fable; anthropic.com/claude-fable-5-5 returns 404 and the docs address for a fable-5-5 model shows “Page not found”.

    By The Frontier Brief · Anthropic model directory ↗ · Second source ↗

  9. Our checkStill no announcementVerifiedour check

    The newsroom shows Opus 5.5, Sonnet 5.5 and Haiku 5.5; the model directory still ends at Fable 5.1.

    By The Frontier Brief · Anthropic newsroom ↗

  10. Leak@pankajkumar_dev: enterprise clients “like Meta, JP Morgan” got access “a week ago”; a new checkpoint “came out yesterday”Predictedauthor claim · unverified

    Repeats the enterprise-rollout claim of October 25 with named customers and adds a fresh checkpoint. No source, screenshot or link in the post. Enterprise access is still unconfirmed at our November 4 check.

    By @pankajkumar_dev · Post on X ↗ · unresolved

  11. Leak@legit_api: a newer Fable checkpoint and a new Opus have entered early testingPredictedauthor claim · unverified

    Shares sample outputs credited to a Discord user and gives neither model a version number. A checkpoint in testing says nothing about a date or a price. TestingCatalog cites the post on November 1.

    By @legit_api · Post on X ↗ · unresolved

  12. Benchmark claim@Layton_Gott: a hidden “Obsidian 3” in Cognition’s FrontierCode 2.0 data beats Opus 5.5 at max effort, 46.8% against 45.5%Predictedauthor claim · unverified

    Read as a possible Fable 5.5 because it ran in the same Claude Code harness as Opus 5.5 and Fable 5.1, on high effort only, at about two thirds of the cost. A 1.3-point gap on one benchmark from a third party’s data, with no model name attached. The only numeric performance claim we have seen.

    By @Layton_Gott · Post on X ↗ · unresolved

  13. OfficialAnthropic files an S-1 for a proposed IPO; the announcement names no modelVerifiedofficial

    The IPO that many posts tie the release to is now a public filing (Nasdaq, symbol ANT; share count and price range not set). The announcement mentions no upcoming model, so it moves no date.

    By Anthropic · Anthropic announcement ↗

  14. Leak@kimmonismus: “Fable 5.5 has been rolled out to enterprise”, consumer release in the “coming week”Predicted · date passedauthor claim · unverified

    Citing a “Chris” as reliable, without a link. The next evening the same account says “probably not today but very very likely this week”. The week of October 26 ended on November 1 with no announcement; the enterprise rollout is still unconfirmed.

    By @kimmonismus · Post on X ↗ · Second source ↗ · date passed

  15. Our checkStill no announcementVerifiedour check

    Anthropic’s model directory lists Fable 5.1 as the newest Fable; the API release notes (through October 22) and newsroom mention no new Fable.

    By The Frontier Brief · Anthropic model directory ↗

  16. Leak@vikktorrrre: “Fable 5.5 (November is certain)”; some users report Sonnet 5.5 routing to itPredictedauthor claim · unverified

    After the October 20 miss, the same account moves the date to November and relays a new routing claim, this time from Sonnet 5.5. The next day it adds that two Claude Code contributors leaving Anthropic means a release “next week”; that week (October 26 to November 1) passed with nothing. No source for either; the November claim is still open.

    By @vikktorrrre · Post on X ↗ · Second source ↗ · unresolved

  17. Leak@StatsWire: “claude-onigiri-eap-2” appears in Artificial Analysis’s front-end JS, then is scrubbedPredictedauthor claim · unverified

    A second codename slug with four effort levels (low, medium, high, xhigh); the post says it was removed about three hours later and the page returned 404. Same caveat as October 15: a codename on a benchmarking site, not a model page.

    By @StatsWire · Post on X ↗ · unresolved

  18. ReportThe Information: a new Anthropic model is with testers; timing later revised to “the coming weeks”Predictedauthor claim · unverified

    The family is not named. The revision is relayed by 36Kr (via Xinzhiyuan); we have not read The Information’s piece ourselves.

    By The Information (via 36Kr) · 36Kr ↗ · relayed; we have not read the original · unresolved

  19. Leak@daniel_mac8: “Fable 5.5 probably definitely tomorrow”; @vikktorrrre the next morning: “coming today, as per sources”Predicted · date passedauthor claim · unverified

    The rumoured traits (better reasoning and intuition, infers intent, fixes root causes) echo The Information’s report of the same day. October 20 passed with no announcement; @mark_k noted that evening that the “today” rumour had turned out to be false.

    By @daniel_mac8; @vikktorrrre (October 20) · Post on X ↗ · Second source ↗ · date passed

  20. Leak@lyraxana: “Partners got access to the upcoming Claude Fable 5.5”, guessing “next week”Predicted · date passedauthor claim · unverified

    @AiBattle_ repeats it on October 16. The week of October 19–23 passed with no release; partner access is unresolved.

    By @lyraxana; @AiBattle_ · TestingCatalog, October 17 ↗ · date passed

  21. Leak@LuminaBench: a codename “claude-onigiri-eap” in Artificial Analysis’s front-end codePredictedauthor claim · unverified

    Found in the benchmark site’s JavaScript with four effort levels and a fallback to Opus 4.8; read as a possible Fable 5.5 being benchmarked under early access. LuminaBench’s own write-up (read November 4) gives the slug as claude-onigiri-eap-2 and says the code does not confirm it is Fable 5.5. A codename on a third-party site names no model.

    By @LuminaBench (relayed by @AGTPinsights, @letdarky, @HarshithLucky3) · LuminaBench journal ↗ · Second source ↗ · unresolved

  22. Our checkOur check: LiteLLM’s git history confirms the Azure listing and its removalVerifiedour check

    The price-sync bot added azure_ai/claude-fable-5-5 on October 13 at 05:27 Pacific (pull request 46201), with $10 / $50 per million tokens, a 1M context and an Azure East US 2 catalog URL as its source. On October 14 at 09:16 Pacific another bot removed it (pull request 46428) with the note “which Azure does not list”. The row before this one is confirmed; it is still a catalog entry, not a release.

    By The Frontier Brief · LiteLLM commit adding the entry ↗ · Second source ↗

  23. LeakAn unsourced post relays that “Leo” says Fable 5.5 ships “this week”Predicted · date passedauthor claim · unverified

    The week of October 13 passed with no release.

    By An unnamed X account (via TestingCatalog) · TestingCatalog, October 17 (context) ↗ · date passed

  24. Listingazure_ai/claude-fable-5-5 appears in LiteLLM’s price sync, then is removedRetractedauthor claim · unverified

    LiteLLM’s bot copied it from Azure’s East US 2 catalog marked “Generally available”, with prices copied from Fable 5.1 ($10 / $50, 1M context). Removed about a day later after Azure queries came back empty. The strongest trace so far: it suggests the name is real; it is not a release.

    By LiteLLM’s price-sync bot, from Azure’s catalog (via TestingCatalog) · TestingCatalog, October 17 ↗ · Second source ↗

  25. LeakSeveral accounts: some Opus 5.5 requests reach a newer, stronger modelPredictedauthor claim · unverified

    @marmaduke091, @kimmonismus, @chetaslua and @LuminaBench (October 11–12). TestingCatalog notes it could be Opus 5.6 as easily as Fable 5.5.

    By @marmaduke091, @kimmonismus, @chetaslua, @LuminaBench (via TestingCatalog) · TestingCatalog ↗ · unresolved

  26. Leak@haider1: “intel from a Google employee”: Fable 5.5 “looks likely to launch this month”Predicted · date passedauthor claim · unverified

    Second-hand from an unnamed employee at a competitor, who also predicts OpenAI’s “Bel” will pass it by December. October ended with no announcement.

    By @haider1 · Post on X ↗ · date passed

  27. OfficialAnthropic releases Haiku 5.5Verifiedofficial

    The last model Anthropic had pre-announced. Nothing else is pre-announced.

    By Anthropic · Anthropic announcement ↗

  28. Our checkOctober 6 passes with no announcementVerifiedour check

    The first leaked date is missed.

    By The Frontier Brief · Anthropic newsroom ↗

  29. Leak@LuminaBench: Claude Code now saves a rolling Fable choicePredictedauthor claim · unverified

    Read by the poster as grey-scale testing. Claude Code’s own docs describe “fable” as a documented rolling alias, which is not evidence of a new model.

    By @LuminaBench · Post on X ↗ · unresolved

  30. Leak@blueemi99: “Fable 5.5 is so mindblowing, it can do like everything”Predictedauthor claim · unverified

    An account describes using the model: one hour-long prompt does what Opus 5.5 would need many prompts for. Nothing in the post we saw shows which model answered. @oalanicolas says the same on October 14, in Portuguese, after “three days” of use. Hands-on claims without outputs we can check.

    By @blueemi99; @oalanicolas (October 14) · Post on X ↗ · Second source ↗ · unresolved

  31. Leak@AndrewCurran_: “We now know the name of that model: Fable 5.5”Predictedauthor claim · unverified

    A widely followed AI watcher states the name as settled, without saying where it comes from, and expects the strongest release to be held until just before the IPO. A name, not a date or a price.

    By @AndrewCurran_ · Post on X ↗ · unresolved

  32. Leak@Mr_Salio: “Fable 5.5 leaks: beats Opus 5.5”, “already secretly rolling out”, “appeared in Anthropic’s docs”Predictedauthor claim · unverified

    A list of claims in one post: better than Opus 5.5 in early tests, a quiet rollout, silent routing while the UI says 5.1, and an appearance in Anthropic’s docs. No numbers and no link to a test. Anthropic’s model directory lists no Fable 5.5, and anthropic.com/claude-fable-5-5 returns 404 (checked October 31 and again November 4).

    By @Mr_Salio · Post on X ↗ · unresolved

  33. Leak@kimmonismus repeats the October 6 datePredicted · date passedauthor claim · unverified

    Adds “I can’t verify any of this.” Same claim as the day before, so it counts once.

    By @kimmonismus · Post on X ↗ · date passed

  34. Leak@bridgemindai: Fable 5.5 will land before an Anthropic IPO “coming in November”Predictedauthor claim · unverified

    The first of many posts that tie the release to an IPO, with no source for either date. Anthropic did file an S-1 on October 26 (see that row); the filing announcement says nothing about a model.

    By @bridgemindai · Post on X ↗ · unresolved

  35. Leak@imjustnewatai: release “next week … I’m hearing of a Tuesday release”Predicted · date passedauthor claim · unverified

    That would have been Tuesday, October 6. About 307,000 views. October 6 passed with no announcement.

    By @imjustnewatai · Post on X ↗ · date passed

  36. Leak@chetaslua: “Fable 5.5 is auto routing on web”Predictedauthor claim · unverified

    A screenshot captioned “label says 5.1, knows the reset guy.” About 652,000 views when we read it. From here on the leakers say “5.5”, not “5.2”.

    By @chetaslua · Post on X ↗ · unresolved

  37. OfficialAnthropic releases Sonnet 5.5Verifiedofficial

    The second 5.5 model. Still no Fable.

    By Anthropic · Anthropic announcement ↗

  38. OfficialAnthropic releases Opus 5.5Verifiedofficial

    Released on the Tuesday TestingCatalog had pointed to. No Fable announcement.

    By Anthropic · Anthropic announcement ↗

  39. ReportTestingCatalog reports stealth tests of Fable 5.2 alongside Opus 5.5Predictedauthor claim · unverified

    The Opus 5.5 half came true the next day. The Fable half is still unresolved.

    By TestingCatalog · TestingCatalog ↗ · unresolved

  40. Leak@chetaslua: “Fable 5.2 is tested in Claude Code”Predictedauthor claim · unverified

    Says some Fable 5.1 requests were routed to a newer model; @notjazii reported similar routing. Routing shows a different answer came back, not a name, date or price.

    By @chetaslua · Post on X ↗ · unresolved

  41. Leak@Mr_Salio: a fresh Fable run could land late September or early OctoberPredictedauthor claim · unverified

    Relayed in Kingy’s compilation; we have not read the original post ourselves, so it is not scored.

    By @Mr_Salio (via Kingy’s compilation) · Kingy’s compilation ↗ · relayed; we have not read the original · unresolved

  42. OfficialAnthropic releases Fable 5.1Verifiedofficial

    Fable 5.1 becomes the current Fable model. Nothing about a 5.2 or 5.5 is announced with it.

    By Anthropic · Anthropic announcement ↗

Ranked newest first for now; ranking by reach (the original post’s view count, recorded once with its date) starts when the reach field is filled. A screenshot, a routing test or a catalog row is not a release; an announcement from Anthropic, a model ID in the docs or a price is.

Works · author’s claim

Made with Fable 5.5 before release

All works →
Meanwhile

What people make with Opus 5.5, Sonnet 5.5, Fable 5.1

All works →

These are not Fable 5.5 works; each card names the model its author says they used.

After launch

Works, reviews and usage-limit changes

Not released yet. Checked Nov 5, 2026: Anthropic newsroom, model directory and API release notes. Anthropic has not announced Fable 5.5, so nothing goes here until it does. Release date: not announced.

  • Works made with it

    Posts in which the author says they used Fable 5.5, credited and linked to the post, each with the “author’s claim” line.

  • Reviews and coding evaluations

    Who tested what, their conclusion in our words, labelled Independent, Vendor-reported, Early test or Reported.

  • Usage-limit changes

    Any change to the weekly or five-hour limits that Anthropic publishes with the model, linked to the page that says so.

Get ready

Before it ships

On release day this page switches to its released layout: official facts first, then works, reviews and limit changes, with the claims above folded into a record of what came true.

Tell me when it ships / free

Hear once, when it is real.

One email when Anthropic officially announces Fable 5.5: the price, which plans include it, and where to use it. Nothing for rumors.

What to hear about

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From the Skill store

Video Skills people start with

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  • FreeVideo

    Every Screen Agent

    An agent finishes a job on a laptop; the result shows up on a phone, then in a terminal, a chat and a code review. A 6.8-second light product shot.

    See it in the catalog →
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    Warp Liftoff

    A blue spiral galaxy, a flash and a rocket climbing off a planet, then your headline and button. An 11-second dark launch teaser.

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    Paint Sweep Finale

    A paint stroke wipes the frame, your wordmark is painted on letter by letter, and torn paper brings in the tagline. 8.6 seconds.

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    A data-broker listing is scanned, crumbles into dust, and your payoff types on in blue. A 7-second privacy-product sting.

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FAQ

Questions about Fable 5.5

Is Fable 5.5 out?

No (checked Nov 5, 2026: Anthropic newsroom, model directory and API release notes). No release date is announced. A screenshot, a routing test or a catalog row is not a release; an announcement from Anthropic, a model ID in the docs or a price is.

What do the labels on the claims mean?

“Official” is Anthropic’s own page. “Our check” is something we looked up ourselves, with the link. “Author claim · unverified” is everything else: a post, a report or a listing we can link to but cannot confirm. Dates of X posts are read from the post IDs; “seen in search results only” means we read the post’s text in a search result and did not open it.

Were these works really made with this model?

That is the author’s claim. We cannot see which model actually ran, so every card carries an “author’s claim” line, and we say when an author works for the model’s maker.

I made one of these. Can I have it removed?

Yes. Email [email protected] with the link and we take it down within two working days.

Today: Fable 5.5 rumors