diff --git a/bun.lock b/bun.lock
index 0bf24c397..c691aea45 100644
--- a/bun.lock
+++ b/bun.lock
@@ -228,6 +228,7 @@
       "version": "17.2.14",
       "dependencies": {
         "@oh-my-pi/pi-ai": "catalog:",
+        "@oh-my-pi/pi-catalog": "catalog:",
         "@oh-my-pi/pi-natives": "catalog:",
         "@oh-my-pi/pi-utils": "catalog:",
         "@oh-my-pi/pi-wire": "catalog:",
diff --git a/packages/snapcompact/CHANGELOG.md b/packages/snapcompact/CHANGELOG.md
index b6fce27a2..f694be1d7 100644
--- a/packages/snapcompact/CHANGELOG.md
+++ b/packages/snapcompact/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed `claude-opus-5` (and later Opus lines) falling back to the 1568px frame instead of the 1932px high-res tier, so snapcompact archives for the current flagship Opus now retain ~33% more history at the same per-frame bill ([#8256](https://github.com/can1357/oh-my-pi/issues/8256)).
+
 ## [17.1.5] - 2026-07-27
 
 ### Fixed
diff --git a/packages/snapcompact/package.json b/packages/snapcompact/package.json
index a41026457..6e0f8025a 100644
--- a/packages/snapcompact/package.json
+++ b/packages/snapcompact/package.json
@@ -32,6 +32,7 @@
   },
   "dependencies": {
     "@oh-my-pi/pi-ai": "catalog:",
+    "@oh-my-pi/pi-catalog": "catalog:",
     "@oh-my-pi/pi-natives": "catalog:",
     "@oh-my-pi/pi-utils": "catalog:",
     "@oh-my-pi/pi-wire": "catalog:"
diff --git a/packages/snapcompact/src/snapcompact.ts b/packages/snapcompact/src/snapcompact.ts
index dce081240..a07c8ef0e 100644
--- a/packages/snapcompact/src/snapcompact.ts
+++ b/packages/snapcompact/src/snapcompact.ts
@@ -46,6 +46,7 @@
  */
 
 import type { Api, ImageContent, Message, TextContent } from "@oh-my-pi/pi-ai";
+import { isFableOrMythos, parseAnthropicModel, semverGte } from "@oh-my-pi/pi-catalog/identity";
 import { renderSnapcompactPng, snapcompactSupportedChars } from "@oh-my-pi/pi-natives";
 import { formatGroupedPaths, prompt } from "@oh-my-pi/pi-utils";
 import { INTENT_FIELD } from "@oh-my-pi/pi-wire";
@@ -336,17 +337,17 @@ export interface IdealShape {
 	frameSize?: number;
 }
 
-/** Eval-winning format per model line, matched against the model id. The
- *  wire API only identifies the gateway — a Claude served through Vertex or
- *  OpenRouter still reads best with its own shape. Patterns cover the model
- *  lines the mono evals measured; everything else falls back to the API
- *  family's winner at the standard 1568px frame. First match wins. */
+/** Eval-winning format per model line. The wire API only identifies the
+ *  gateway — a Claude served through Vertex or OpenRouter still reads best
+ *  with its own shape. Classified Anthropic models use the shared catalog
+ *  identity parser; remaining model lines use first-match regex rules and fall
+ *  back to the API family's winner at the standard 1568px frame. */
+const HIGH_RES_ANTHROPIC_VARIANT = { variant: "11on16-bw", frameSize: 1932 } as const satisfies IdealShape;
 const MODEL_VARIANTS: readonly (readonly [RegExp, IdealShape])[] = [
-	// Opus 4.7+ and Fable/Mythos read high-res natively (2576px edge under a
-	// 4,784 visual-token cap → 1932px square sweet spot): same recall and
-	// cost as 1568, a third fewer frames.
-	[/claude.*(fable|mythos)/i, { variant: "11on16-bw", frameSize: 1932 }],
-	[/claude-?opus-?4[.-][7-9]/i, { variant: "11on16-bw", frameSize: 1932 }],
+	// Versionless Fable/Mythos aliases (e.g. `claude-fable-latest`) never parse
+	// a numeric version, so keep them on the high-res tier by name — every
+	// Fable/Mythos line reads it natively.
+	[/claude.*(fable|mythos)/i, HIGH_RES_ANTHROPIC_VARIANT],
 	// Older Claude lines downscale past 1568px — keep the safe size.
 	[/claude/i, { variant: "11on16-bw" }],
 	// Gemini 3.x bills a fixed 1,120-token budget per image regardless of
@@ -363,6 +364,18 @@ const MODEL_VARIANTS: readonly (readonly [RegExp, IdealShape])[] = [
 
 /** Eval-ideal format for a model id, or undefined when unmeasured. */
 export function idealShapeVariant(modelId: string): IdealShape | undefined {
+	const anthropic = parseAnthropicModel(modelId);
+	if (
+		anthropic &&
+		(isFableOrMythos(anthropic.kind) || (anthropic.kind === "opus" && semverGte(anthropic.version, "4.7")))
+	) {
+		// Opus 4.7+ and Fable/Mythos read high-res natively: same recall and
+		// cost as 1568, a third fewer frames. 1932 is the largest *square* not
+		// downscaled under Anthropic's 4,784 visual-token cap ((1932/28)² =
+		// 69² = 4,761 ≤ 4,784 28px patches), and staying below 2000px clears
+		// the stricter ≤2000px limit for requests with more than 20 images.
+		return HIGH_RES_ANTHROPIC_VARIANT;
+	}
 	return MODEL_VARIANTS.find(([pattern]) => pattern.test(modelId))?.[1];
 }
 
diff --git a/packages/snapcompact/test/snapcompact.test.ts b/packages/snapcompact/test/snapcompact.test.ts
index fd6734bd4..c785b8ee1 100644
--- a/packages/snapcompact/test/snapcompact.test.ts
+++ b/packages/snapcompact/test/snapcompact.test.ts
@@ -299,6 +299,26 @@ describe("shape resolution", () => {
 		// High-res frames are reserved for the lines that read them natively;
 		// older Claude lines keep the safe 1568px family default.
 		expect(snapcompact.resolveShape({ api: "anthropic-messages", id: "claude-opus-4-8" }).frameSize).toBe(1932);
+		expect(snapcompact.resolveShape({ api: "anthropic-messages", id: "anthropic--claude-4.8-opus" }).frameSize).toBe(
+			1932,
+		);
+		expect(snapcompact.resolveShape({ api: "anthropic-messages", id: "claude-opus-4-10" }).frameSize).toBe(1932);
+		// Versionless Fable/Mythos aliases (bundled `claude-fable-latest`) never
+		// parse a numeric version but still read the high-res tier by name (#8257).
+		expect(
+			snapcompact.resolveShape({ api: "openai-completions", id: "anthropic/claude-fable-latest" }).frameSize,
+		).toBe(1932);
+		expect(
+			snapcompact.resolveShape({ api: "openai-completions", id: "~anthropic/claude-fable-latest" }).frameSize,
+		).toBe(1932);
+		// Opus 5+ shares the Anthropic visual-token cap, so it stays on the
+		// high-res tier rather than falling back to the 1568px default (#8256).
+		expect(snapcompact.resolveShape({ api: "anthropic-messages", id: "claude-opus-5" }).frameSize).toBe(1932);
+		expect(snapcompact.resolveShape({ api: "anthropic-messages", id: "claude-opus-6" }).frameSize).toBe(1932);
+		// Opus lines below 4.7 downscale, so they keep the safe family default.
+		expect(snapcompact.resolveShape({ api: "anthropic-messages", id: "claude-opus-4-6" })).toBe(
+			snapcompact.SHAPES.anthropic,
+		);
 		expect(snapcompact.resolveShape({ api: "anthropic-messages", id: "claude-3-5-sonnet" })).toBe(
 			snapcompact.SHAPES.anthropic,
 		);