News Anthropic
The next Claude model is very close
Editorial cover by HeyMark.
Updated · November 3, 2026. The name Mythos 5.5 appeared in the HTML of Anthropic’s own website. We downloaded two archived copies of its Mythos page: the October 31 copy contains it; in the November 1 copy, the label says 5.1. That gives us something new to compare directly, alongside the release history we analyzed yesterday.
What changed between the two copies of Anthropic’s page
Before and after on Anthropic’s site
Two captures of the same Mythos page, saved by Internet Archive.
21:49:26 UTC
Claude Claude Mythos 5.5
6 mentions of Mythos 5.5
Open capture ↗20:05:45 UTC
Claude Mythos 5.1
0 mentions of Mythos 5.5
Open capture ↗6 mentions = 3 fields + their duplicates
One hidden heading and the alternative text of two logos. The data used to initialize the page repeats those three values.
- Hidden heading · h1
- Desktop logo · alt
- Mobile logo · alt
The original phrase repeats “Claude”: Claude Claude Mythos 5.5. Both versions retain Mythos 5.1 content elsewhere on the page. The change could fit editorial preparation or a copy error; these files do not establish which explanation is correct.
To check it yourself, download the original HTML using the rawUrl links in our verification file. Replace that entire phrase with Claude Mythos 5.1 in the October 31 copy, then compare the files. That operation removes every difference between the two saved responses.
Why Mythos also puts the focus on Fable
The connection comes from Anthropic’s official FAQ: Fable 5.1 and Mythos 5.1 share the underlying model. Fable adds safeguards for general availability. This relationship exists independently of the release tracker.
It makes sense to watch Fable when a reference to another Mythos version appears. The possibility of both families receiving an update together remains our inference. The sources reviewed do not announce a Fable/Mythos 5.5 pair or provide a date.
The LiteLLM reference that was already removed
The identifier azure_ai/claude-fable-5-5 also circulated in LiteLLM’s cost registry. PR 46428, merged on October 14, removed that entry from two files. The correction record explains that Azure did not list the model and that test calls returned 404 DeploymentNotFound.
Those checks are documented by LiteLLM; we did not make authenticated Azure calls. The removed entry does not establish that Fable 5.5 was available. The archived HTML provides a separate trace from Anthropic’s own website, whose scope you can inspect above.
What we can know about the next Claude today
On November 3, the Mythos page shows 5.1 again, and the Claude Platform catalog still lists claude-fable-5-1. These sources still provide no official date or published benchmarks for a successor.
The finding changes the available evidence: there is now a name observed in an archived copy of Anthropic’s site. The calendar below explains the earlier expectation, but does not turn that mention into a scheduled release.
The tracker as we observed it on November 2
On November 2, AI Release Tracker showed November 3 for Anthropic’s next model release. When we opened its company page in the browser, the counter said one day remained. It also kept an earlier date: October 28, marked as five days overdue.
October 28 comes from recent release gaps. November 3 appears when the counter moves forward after that estimate has passed. We found no Anthropic announcement confirming November 3 in the official sources reviewed. The latest model we verified was Haiku 5.5, announced on October 7. Haiku announcement · Official release notes.
Where October 28 and November 3 come from
The tracker takes the five most recent gaps between release days, calculates their median and adds it to the latest release date. Models announced on the same date count as a single event. It also moves the result to the nearest Monday–Thursday. Its published methodology explains both rules.
For Anthropic, the calculation is reproducible: the gaps are 24, 39, 21, 6 and 9 days. Sorted, they become 6, 9, 21, 24 and 39. The middle value is 21; adding it to October 7 gives October 28, already a Wednesday, so no adjustment was needed.
A separate rule applies afterward. If that date passes without a recorded release, the site keeps the missed projection and displays the next occurrence of the weekday most common in its history. Here that is Tuesday, producing November 3. The tracker itself says this repositioning does not improve the forecast. It adds no leak, announced event or new information from Anthropic. How missed dates are handled.
Claude releases
AI Release Tracker ↗Fable 5.1 ·
AI Release Tracker records Claude Fable 5.1 on 1 September 2026. View source ↗
Mythos 5.1 ·
AI Release Tracker records Claude Mythos 5.1 on 1 September 2026. View source ↗
Opus 5.5 ·
AI Release Tracker records Claude Opus 5.5 on 22 September 2026. View source ↗
Sonnet 5.5 ·
AI Release Tracker records Claude Sonnet 5.5 on 28 September 2026. View source ↗
Haiku 5.5 ·
Anthropic released Haiku 5.5 on October 7. It is the latest model launch we verified in official sources. View source ↗
Expected ·
The tracker added 21 days to Haiku 5.5’s release: October 7 + 21 = October 28. That date passed without a newly recorded model. View source ↗
Now expected ·
The tracker now shows November 3, one day after our observation. Once the first date passed, its rule moved the counter to the next Tuesday. View source ↗
Dashed border: dates calculated by the tracker. The other items are models already released.
Observed Nov 2, 2026 · 14:49 UTC. 26 days have passed since Haiku 5.5.
The current wait is still open and is not included as a completed gap in the median.
6 · 9 · 21 · 24 · 39 Median: 21 days. Oct 7 + 21 = Oct 28.
Try a different sample
We recalculate the median and apply the same nearest Monday–Thursday adjustment. This shows how much the result depends on the sample.
| Sample | Median | Raw date | Adjusted |
|---|---|---|---|
| Last 3 gaps | 9 days | 16 Oct | 15 Oct |
| Last 5 gaps | 21 days | 28 Oct | 28 Oct |
| Full history | 42 days | 18 Nov | 18 Nov |
These are illustrative HeyMark calculations, not new forecasts. A different sample does not establish a more likely date. November 3 comes from a separate rule: moving the counter to the next Tuesday.
The days recorded by the tracker
| Date | Models recorded |
|---|---|
| Claude Haiku 5.5 | |
| Claude Sonnet 5.5 | |
| Claude Opus 5.5 | |
| Claude Fable 5.1 / Claude Mythos 5.1 | |
| Claude Opus 5 | |
| Claude Sonnet 5 | |
| Claude Fable 5 / Claude Mythos 5 | |
| Claude Opus 4.8 | |
| Claude Opus 4.7 | |
| Claude Sonnet 4.6 | |
| Claude Opus 4.6 | |
| Claude Opus 4.5 | |
| Claude Haiku 4.5 | |
| Claude Sonnet 4.5 | |
| Claude Opus 4.1 | |
| Claude Sonnet 4 / Claude Opus 4 | |
| Claude 3.7 Sonnet | |
| Claude 3.5 Haiku / Claude 3.5 Sonnet (upgraded) | |
| Claude 3.5 Sonnet | |
| Claude 3 Haiku / Claude 3 Sonnet / Claude 3 Opus | |
| Claude 2.1 | |
| Claude Instant 1.2 | |
| Claude 2 | |
| Claude 1 |
30 records grouped into 24 dates and 23 gaps. Tracker history; not an official audit of every announcement.
AI Release Tracker ↗ · Published methodology · CSV · Our calculation and sources
The wait has exceeded the recent pace. How much does that tell us?
At the November 2 observation, 26 days had passed since Haiku. That exceeds the recent 21-day median, but the median is not a deadline Anthropic committed to meeting.
A different sample changes the date. With only the last three gaps, the median falls to 9 days: the raw sum lands on October 16, and the weekday adjustment moves it to October 15. Using all 23 gaps between distinct dates in the collected history raises it to 42 days, producing November 18. These are our calculations using tracker records, not alternative release dates. Open “See how it is calculated” to change the sample, or inspect the CSV.
This is why the counter needs context. The same history yields different dates depending on which portion we use. Passing one of them does not establish a verified probability that a model will arrive the following day.
The calendar mixes families; it does not identify the next Claude
The six release days in the sample include Sonnet 5, Opus 5, Fable/Mythos 5.1, Opus 5.5, Sonnet 5.5 and Haiku 5.5. Official product notes confirm the recent sequence: Opus 5.5 on September 22, Sonnet on September 28 and Haiku on October 7. These are different tiers and versions in the lineup, not six complete generations. Official product history.
“Another Anthropic model” therefore does not identify Claude 6, another Opus or a Fable update. The earlier speculation about Fable 5.5 is a different kind of signal, with its own sources and limits; the calendar does not confirm that name.
Nor should every development carrying the Claude name reset this clock. Duet, announced on October 21, is a proactive agent app built on Opus 5.5. An update to the Claude Code client can also add features without changing the model. What Duet is · Claude Code changes.
What current Claude benchmarks show
If you are waiting before switching models, the date is only part of the decision. There are still no published results for the next Claude in the sources reviewed. We can look at what Opus, Sonnet and Haiku 5.5 already offer: coding, terminal use, reasoning and chart-reading tests measure different capabilities.
The current reference · Claude 5.5
Choose a task to view the published scores.
FrontierCode 1.1 · Main
Code changes evaluated for whether they could be merged without human edits.
Highlight: highest of the displayed scores; settings are not matched.
Opus uses Max and Sonnet uses Xhigh; we did not verify Haiku’s effort for this score. Sonnet reports 46.2% at Max. More effort does not guarantee a higher score.
Next modelNo published benchmarks
Figures from Anthropic; effort, agent and budget are not matched. “Unverified” refers to effort. Opus uses production safeguards and may fall back to other models. Differences do not establish statistical superiority.
| Test | Opus 5.5 | Sonnet 5.5 | Haiku 5.5 |
|---|---|---|---|
| FrontierCode 1.1 · Main | 54.4%Max | 52.1%Xhigh | 46.4%Unverified |
| Terminal-Bench 4.0 | 66.4%Xhigh | 70.6%Unverified | 39.2%Unverified |
| Humanity’s Last Exam | 67.7%With tools | 64.5%With tools | 57.4%With tools |
| Chartography | 64.4%No tools | 61.6%No tools | 46.4%No tools |
FrontierCode 1.1 · Main. Opus uses Max and Sonnet uses Xhigh; we did not verify Haiku’s effort for this score. Sonnet reports 46.2% at Max. More effort does not guarantee a higher score.
Terminal-Bench 4.0. Opus uses Xhigh and its announcement reports a ±2.6-point standard error. These are launch-table figures, not a HeyMark rerun with one agent and budget.
Humanity’s Last Exam. All three results allow tools. They are kept separate from no-tools scores and are not a success rate for arbitrary tasks.
Chartography. Opus’s 64.4% comes from the Sonnet table, without tools. The 89.0% in the Opus announcement allows tools: that is a different configuration and is not used here.
Official tables: Opus · Sep 22 · Sonnet · Sep 28 · Haiku · Oct 7
Sonnet reports 70.6% on Terminal-Bench 4.0 versus Opus’s 66.4%, while the FrontierCode table lists 54.4% for Opus at Max and 52.1% for Sonnet at Xhigh. Settings are not matched. There is no universal winner: the task and reasoning effort change. These are results from Anthropic’s announcements, not our own tests or evidence about the model that comes next. Sonnet table · Opus table.
What would establish a release date?
Our November 2 review of the Anthropic newsroom, product notes and Claude Platform notes found no model announcement after Haiku 5.5.
An announcement identifying the model, availability and date would provide Anthropic’s information to plan around. The counter explains the expectation, but supplies no name, access terms or results for a future model.
Update verified: November 3, 2026, 13:33 UTC. Comparison of two archived HTML responses and review of the linked sources. The tracker section preserves the November 2 observation at 14:49 UTC; its displayed date may change. HeyMark calculations and file comparison, with no internal Anthropic information.
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