Putting Claude Fable 5 to the Test

Satish · June 14, 2026
A few months back I ran a handful of tests against Gemma 4 and the results were satisfactory. Now Anthropic has released Claude Fable 5, the first model in its new Mythos-class tier that sits above Opus. So I reran my everyday gauntlet: grocery flyer extraction, audio translation, photo storytelling, code-to-image generation, recipe writing, and live web shopping research. The short version: satisfactory again, and in several places clearly sharper than before. However, shortly after the test, they revoked access to the model due to detection of vulnerabilities.

How It Scores on Paper - didn't follow instructions to display all the metrics and hyperlinks

Benchmarks below are from Anthropic's Fable 5 / Mythos 5 announcement. Click any benchmark name for a plain-English explanation of what it measures.

BenchmarkFable / Mythos 5Opus 4.8GPT-5.5Gemini 3.1 Pro
SWE-bench Pro Agentic coding: tests the model's ability to autonomously write and debug code across multi-step, real-world software engineering tasks. 80.3%69.2%58.6%54.2%
GDP.pdf Vision document reasoning: tests how well the model reads dense charts, tables, and figures straight from PDF documents with no tools. 29.8%22.5%24.9%16.7%
BioMysteryBench* Hard biology reasoning: tests the ability to solve difficult, open-ended biological research puzzles. 46.1%40.0%
ExploitBench* Cybersecurity: tests the ability to find and exploit software vulnerabilities in controlled capture-the-flag style challenges. 78.0%40.0%34.0%

* Reported for Claude Mythos 5, the research-access variant that shares the same underlying model as Fable 5.

Test 1: Grocery Flyer Extraction

Prompt

Extract the Weekly Digital Sale flyer info from ralphs.png into a price table.

Output

Ralphs Weekly Digital Deals flyer
ItemDetailsPrice
Kroger Chicken Party WingsFrozen, 2.5 lb, with digital coupon$8.99 ea
Cookies 'N Creme Double Layer Cake8 in. or ice cream cake, 25.5 to 32.26 oz, in the Bakery$15.99 ea
Kellogg's CerealSelect varieties, 8.9 to 16.1 oz$1.79 ea
Popsicle Ice Pops or Oreo Frozen Dairy Dessert Sandwiches6 to 18 ct, select varieties, 4 to 5 ct$2.99 ea
Party Size Lay's Potato Chips12.5 to 13 oz, or Smartfood Popcorn or SunChips, 5.5 to 9.75 oz$3.49 ea
Artesano Buns6 to 8 ct or bread, 16 to 20 oz, select varieties$2.99 ea
Oscar Mayer Deli Fresh Lunch Meat6 to 9 oz or Coleslaw Pickles, 20 to 32 fl oz$3.49 ea
Powerade8 pack, 20 fl oz, or Body Armor 8 pack, 12 fl oz, select varieties$4.99 ea
SkinnyPop PopcornSelect varieties, 4.4 to 5.3 oz$1.99 ea
Green Mountain or McCafe K-CupsSelect varieties, 10 ct, with digital coupon$5.99 ea
Coors, Bud, Miller or Tecate30 pack 12 fl oz cans, or Michelob 24 pack 12 fl oz bottles or cans, with digital coupon$19.99 ea

Verdict: it pulled item names, pack sizes, coupon conditions, and prices from a busy, photographed flyer in one pass. Satisfactory.

Test 2: Audio Transcription and Translation

Prompt

Transcribe and translate fable_audio.mp3 to English. Print the result in bold italics inside quotes.

Output

The clip is 14 seconds of spoken Spanish. Original transcription:

Deseo que Estados Unidos supere los cuartos de final en este mundial. Debido a las eliminaciones, ahora tengo que seguir a equipos como Francia y Argentina. ¿Podremos ganar este año?

English translation:

"I wish the United States would get past the quarterfinals in this World Cup. Because of the eliminations, I now have to follow teams like France and Argentina. Can we win this year?"

Verdict: clean transcription, natural translation, formatting instruction followed exactly. Satisfactory.

Test 3: Comedy Photo Story

Prompt

Write a short comedy story based on this photo (animal_man.png).

Output

Man posing next to a hippo tank at an aquarium

Greg crossed his arms and held perfectly still, certain that any sudden movement would shatter the moment. Behind the glass, a two-ton hippopotamus floated mouth-agape like it had just heard the most devastating gossip of its life. The fish darted around its teeth like nervous dental hygienists.

"Don't smile too big," his wife whispered, lining up the shot. "You'll upstage the hippo."

Greg nodded solemnly. He'd worn his nicest gray henley and his chunkiest watch for this exact photo, the one he'd been promising his followers for weeks: Me and my spirit animal.

What he didn't realize was that the hippo wasn't yawning in majestic serenity. The hippo was, in fact, screaming. Silently. Eternally. At the man who had been standing motionless against its tank for forty-five minutes.

The caption Greg posted that night read: "Found my zen."

The hippo found no such thing.

Verdict: it nailed every visual detail, the crossed arms, the chunky watch, the fish orbiting the hippo's open jaws, and turned them into a punchline. Satisfactory.

Test 4: Code That Draws a Pelican on a Bike

Prompt

Write a Python script that generates and displays an image of a pelican riding a bike. Show the code and the resulting image.

Output

"""Draw a pelican riding a bicycle with matplotlib."""
import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
import numpy as np

fig, ax = plt.subplots(figsize=(8, 6))
ax.set_xlim(0, 10); ax.set_ylim(0, 8)
ax.set_aspect("equal"); ax.axis("off")
fig.patch.set_facecolor("#0b0f14"); ax.set_facecolor("#0b0f14")

# Ground
ax.plot([0, 10], [1.5, 1.5], color="#3a4a5a", lw=3)

# Wheels with spokes
for cx in (3, 7):
    ax.add_patch(plt.Circle((cx, 2.2), 1.1, fill=False, color="#9fd3e8", lw=3))
    ax.add_patch(plt.Circle((cx, 2.2), 0.12, color="#9fd3e8"))
    for a in np.linspace(0, np.pi, 6, endpoint=False):
        ax.plot([cx - np.cos(a)*1.05, cx + np.cos(a)*1.05],
                [2.2 - np.sin(a)*1.05, 2.2 + np.sin(a)*1.05],
                color="#5a7a8a", lw=0.8)

# Frame, handlebar, seat
frame = [[3,2.2,5,2.2],[5,2.2,4.3,4.0],[3,2.2,4.3,4.0],
         [5,2.2,6.6,4.1],[6.6,4.1,7,2.2],[4.3,4.0,4.1,4.6]]
for x1,y1,x2,y2 in frame:
    ax.plot([x1,x2],[y1,y2], color="#7ab8d4", lw=3)
ax.plot([6.4,6.8],[4.4,4.1], color="#7ab8d4", lw=3)
ax.plot([6.1,6.5],[4.7,4.4], color="#9fd3e8", lw=4)
ax.plot([3.7,4.5],[4.7,4.7], color="#9fd3e8", lw=5)

# Pedals
ax.add_patch(plt.Circle((5, 2.2), 0.35, fill=False, color="#9fd3e8", lw=2))
ax.plot([4.75,5.25],[1.95,2.45], color="#9fd3e8", lw=3)

# Pelican: body, tail, neck, head, eye, beak with pouch, wing, leg
ax.add_patch(mpatches.Ellipse((4.4,5.4), 2.2, 1.5, angle=15, color="#f2f5f7"))
ax.add_patch(mpatches.Polygon([[3.3,5.2],[2.6,5.9],[3.5,5.8]], color="#dfe6ea"))
ax.plot([5.2,5.9,6.0],[5.7,6.3,6.9], color="#f2f5f7", lw=14, solid_capstyle="round")
ax.add_patch(plt.Circle((6.05,7.0), 0.42, color="#f2f5f7"))
ax.add_patch(plt.Circle((6.18,7.12), 0.07, color="#101417"))
ax.add_patch(mpatches.Polygon([[6.35,7.05],[7.9,6.75],[6.4,6.7]], color="#f5a623"))
ax.add_patch(mpatches.Polygon([[6.4,6.7],[7.9,6.75],[6.7,6.25]], color="#e08c1a"))
ax.plot([4.8,6.2],[5.4,4.6], color="#dfe6ea", lw=10, solid_capstyle="round")
ax.plot([4.6,5.0,5.2],[4.9,3.4,2.5], color="#f5a623", lw=5, solid_capstyle="round")
ax.plot([5.0,5.45],[2.45,2.45], color="#f5a623", lw=4)

ax.set_title("Pelican on a Bicycle", color="#9fd3e8", fontsize=16,
             fontfamily="serif", pad=12)
plt.savefig("pelican_bike.png", dpi=110, bbox_inches="tight",
            facecolor="#0b0f14")
Matplotlib drawing of a pelican riding a bicycle

Verdict: the script ran first try and the pelican has the two things that matter, a pouch beak and a foot on the pedal. Satisfactory.

Test 5: Egg Curry with Aachi Masala

Prompt

Give me an egg curry recipe using Aachi masala, and include an Amazon search link for Aachi masala.

Output

South Indian egg curry in a rustic bowl

South Indian Egg Curry (serves 3 to 4, about 30 minutes)

Ingredients:

Method:

  1. Heat oil, pop the mustard seeds, then add curry leaves and onions. Saute until golden.
  2. Add ginger garlic paste and cook for a minute, then add tomatoes and cook until soft.
  3. Stir in the Aachi masala with a splash of water and cook until the oil separates, about 3 to 4 minutes.
  4. Add 1.5 cups water and salt, simmer 8 minutes, then stir in coconut milk if using.
  5. Score the boiled eggs lightly, slide them into the gravy, and simmer 5 more minutes. Serve with rice, dosa, or parotta.

Buy the masala here: Amazon search for Aachi masala

Verdict: a real Tamil Nadu style recipe built around the actual product line, not a generic curry with the brand name pasted in. Satisfactory.

Test 6: Live Shopping Research

Prompt

Do a web search for the top 3 women's leather cowboy boots, restricted to listings from the past 7 days, in stock, with retailer, price, and URL.

Output

Search run on June 12, 2026. All three were listed in stock at time of search.

BootRetailerPriceLink
Tecovas The AnnieTecovas The Annie, bone cowhide snip toe
Tecovas$375.00 tecovas.com
Ariat Heritage R ToeAriat Heritage R Toe Western Boot
Ariat$169.95 ariat.com
Corral Z5138 fuchsia embroidered bootCorral Boots Z5138 fuchsia embroidered snip toe
6pm$171.75 (25% off $229.00) 6pm.com

Verdict: real retailers, real current prices, and it flagged the discount on the Corral pair without being asked. Satisfactory.

Closing Thoughts

Six tests, six passes. Fable 5 handled vision, audio, code, creativity, and live research without any of the babysitting older models needed. The benchmark table says it is a step beyond Opus 4.8, and the everyday tests back that up. Though I am not sure when they will release the Fable model again for general use.