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feat(claude): add Fable 5.1 model support #62

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Merged
asfires merged 1 commit into from
Sep 1, 2026
Merged

feat(claude): add Fable 5.1 model support #62

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69 changes: 61 additions & 8 deletions apps/server/src/provider/Layers/ClaudeProvider.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -52,11 +52,49 @@ const CLAUDE_PRESENTATION = {
showInteractionModeToggle: true,
} as const;
const MINIMUM_CLAUDE_OPUS_5_VERSION = "2.1.219";
// Fork-local gate: earliest Claude Code version verified to accept
// `claude-fable-5-1` on this fork. Revisit when upstream ships its own entry.
const MINIMUM_CLAUDE_FABLE_5_1_VERSION = "2.1.257";
const MINIMUM_CLAUDE_FABLE_5_VERSION = "2.1.169";
const MINIMUM_CLAUDE_OPUS_4_8_VERSION = "2.1.154";
const MINIMUM_CLAUDE_OPUS_4_7_VERSION = "2.1.111";

const CLAUDE_MODEL_CATALOG: ReadonlyArray<ServerProviderModel> = [
{
slug: "claude-fable-5-1",
name: "Claude Fable 5.1",
isCustom: false,
capabilities: createModelCapabilities({
optionDescriptors: [
buildSelectOptionDescriptor({
id: "effort",
label: "Reasoning",
options: [
{ value: "low", label: "Low" },
{ value: "medium", label: "Medium" },
{ value: "high", label: "High", isDefault: true },
{ value: "xhigh", label: "Extra High" },
{ value: "max", label: "Max" },
{
value: "ultracode",
label: "Ultracode",
description: "xhigh effort plus multi-agent workflow orchestration",
},
{ value: "ultrathink", label: "Ultrathink" },
],
promptInjectedValues: ["ultrathink"],
}),
buildSelectOptionDescriptor({
id: "contextWindow",
label: "Context Window",
options: [
{ value: "200k", label: "200k" },
{ value: "1m", label: "1M", isDefault: true },
],
}),
],
}),
},
{
slug: "claude-fable-5",
name: "Claude Fable 5",
Expand Down Expand Up @@ -329,6 +367,10 @@ function supportsClaudeOpus5(version: string | null | undefined): boolean {
return version ? compareSemverVersions(version, MINIMUM_CLAUDE_OPUS_5_VERSION) >= 0 : false;
}

function supportsClaudeFable51(version: string | null | undefined): boolean {
return version ? compareSemverVersions(version, MINIMUM_CLAUDE_FABLE_5_1_VERSION) >= 0 : false;
}

function supportsClaudeFable5(version: string | null | undefined): boolean {
return version ? compareSemverVersions(version, MINIMUM_CLAUDE_FABLE_5_VERSION) >= 0 : false;
}
Expand All @@ -345,6 +387,9 @@ function getBuiltInClaudeModelsForVersion(
version: string | null | undefined,
): ReadonlyArray<ServerProviderModel> {
return BUILT_IN_MODELS.filter((model) => {
if (model.slug === "claude-fable-5-1") {
return supportsClaudeFable51(version);
}
if (model.slug === "claude-opus-5") {
return supportsClaudeOpus5(version);
}
Expand All @@ -361,6 +406,11 @@ function getBuiltInClaudeModelsForVersion(
});
}

function formatClaudeFable51UpgradeMessage(version: string | null): string {
const versionLabel = version ? `v${version}` : "the installed version";
return `Claude Code ${versionLabel} is too old for Claude Fable 5.1. Upgrade to v${MINIMUM_CLAUDE_FABLE_5_1_VERSION} or newer to access it.`;
}

function formatClaudeOpus5UpgradeMessage(version: string | null): string {
const versionLabel = version ? `v${version}` : "the installed version";
return `Claude Code ${versionLabel} is too old for Claude Opus 5. Upgrade to v${MINIMUM_CLAUDE_OPUS_5_VERSION} or newer to access it.`;
Expand Down Expand Up @@ -424,6 +474,7 @@ export function normalizeClaudeCliEffort(
}
if (
effort === "xhigh" &&
model !== "claude-fable-5-1" &&
model !== "claude-fable-5" &&
model !== "claude-opus-5" &&
model !== "claude-opus-4-8" &&
Expand Down Expand Up @@ -907,15 +958,17 @@ export const checkClaudeProviderStatus = Effect.fn("checkClaudeProviderStatus")(
claudeSettings.customModels,
DEFAULT_CLAUDE_MODEL_CAPABILITIES,
);
const versionUpgradeMessage = supportsClaudeOpus5(parsedVersion)
const versionUpgradeMessage = supportsClaudeFable51(parsedVersion)
? undefined
: supportsClaudeFable5(parsedVersion)
? formatClaudeOpus5UpgradeMessage(parsedVersion)
: supportsClaudeOpus48(parsedVersion)
? formatClaudeFable5UpgradeMessage(parsedVersion)
: supportsClaudeOpus47(parsedVersion)
? formatClaudeOpus48UpgradeMessage(parsedVersion)
: formatClaudeOpus47UpgradeMessage(parsedVersion);
: supportsClaudeOpus5(parsedVersion)
? formatClaudeFable51UpgradeMessage(parsedVersion)
: supportsClaudeFable5(parsedVersion)
? formatClaudeOpus5UpgradeMessage(parsedVersion)
: supportsClaudeOpus48(parsedVersion)
? formatClaudeFable5UpgradeMessage(parsedVersion)
: supportsClaudeOpus47(parsedVersion)
? formatClaudeOpus48UpgradeMessage(parsedVersion)
: formatClaudeOpus47UpgradeMessage(parsedVersion);

const capabilities = resolveCapabilities
? yield* resolveCapabilities(claudeSettings).pipe(Effect.orElseSucceed(() => undefined))
Expand Down
57 changes: 57 additions & 0 deletions apps/server/src/provider/Layers/ProviderRegistry.test.ts
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Expand Up @@ -1826,6 +1826,63 @@ it.layer(Layer.mergeAll(NodeServices.layer, ServerSettingsModule.layerTest(), Te
),
);

it.effect("includes Claude Fable 5.1 on supported Claude Code versions", () =>
Effect.gen(function* () {
const status = yield* checkClaudeProviderStatus(
defaultClaudeSettings,
claudeCapabilities(),
);
const fable51 = status.models.find((model) => model.slug === "claude-fable-5-1");
assert.strictEqual(fable51?.name, "Claude Fable 5.1");
assert.strictEqual(status.message, undefined);
}).pipe(
Effect.provide(
mockSpawnerLayer((args) => {
const joined = args.join(" ");
if (joined === "--version") return { stdout: "2.1.257\n", stderr: "", code: 0 };
if (joined === "auth status")
return {
stdout: '{"loggedIn":true,"authMethod":"claude.ai"}\n',
stderr: "",
code: 0,
};
throw new Error(`Unexpected args: ${joined}`);
}),
),
),
);

it.effect("hides Claude Fable 5.1 on older Claude Code versions", () =>
Effect.gen(function* () {
const status = yield* checkClaudeProviderStatus(
defaultClaudeSettings,
claudeCapabilities(),
);
assert.strictEqual(
status.models.some((model) => model.slug === "claude-fable-5-1"),
false,
);
assert.strictEqual(
status.message,
"Claude Code v2.1.256 is too old for Claude Fable 5.1. Upgrade to v2.1.257 or newer to access it.",
);
}).pipe(
Effect.provide(
mockSpawnerLayer((args) => {
const joined = args.join(" ");
if (joined === "--version") return { stdout: "2.1.256\n", stderr: "", code: 0 };
if (joined === "auth status")
return {
stdout: '{"loggedIn":true,"authMethod":"claude.ai"}\n',
stderr: "",
code: 0,
};
throw new Error(`Unexpected args: ${joined}`);
}),
),
),
);

it.effect("includes Claude Opus 5 on supported Claude Code versions", () =>
Effect.gen(function* () {
const status = yield* checkClaudeProviderStatus(
Expand Down
9 changes: 9 additions & 0 deletions apps/server/src/provider/ModelManifest.test.ts
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Expand Up @@ -59,6 +59,15 @@ describe("isLegacyModel (bundled manifest)", () => {
it("leaves driver kinds without a manifest entry unflagged", () => {
assert.isFalse(isLegacyModel(BUNDLED_MODEL_MANIFEST, CURSOR, "composer-1.5"));
});

it("keeps fork-added models current even when the manifest omits them", () => {
const upstreamManifest: ModelManifestData = {
version: 1,
currentModels: { claudeAgent: ["claude-fable-5", "claude-opus-5", "claude-sonnet-5"] },
};
assert.isFalse(isLegacyModel(upstreamManifest, CLAUDE, "claude-fable-5-1"));
assert.isFalse(isLegacyModel(BUNDLED_MODEL_MANIFEST, CLAUDE, "claude-fable-5-1"));
});
});

const model = (overrides: Partial<ServerProviderModel>): ServerProviderModel => ({
Expand Down
11 changes: 11 additions & 0 deletions apps/server/src/provider/ModelManifest.ts
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Expand Up @@ -75,12 +75,23 @@ const encodeManifestCache = Schema.encodeEffect(
),
);

/**
* Fork-local catalog additions upstream's manifest does not know about yet.
* The remote manifest is fetched from upstream `main`, so without this
* override every fork-added model would land in the legacy section. Remove a
* slug once upstream's manifest lists it.
*/
const FORK_CURRENT_MODELS: Partial<Record<string, ReadonlyArray<string>>> = {
claudeAgent: ["claude-fable-5-1"],
};

/** True when the manifest classifies `slug` as legacy for `driverKind`. */
export function isLegacyModel(
manifest: ModelManifestData,
driverKind: ProviderDriverKind,
slug: string,
): boolean {
if (FORK_CURRENT_MODELS[driverKind]?.includes(slug)) return false;
const currentModels = manifest.currentModels[driverKind];
if (!currentModels) return false;
return !currentModels.includes(slug);
Expand Down
2 changes: 2 additions & 0 deletions packages/contracts/src/model.ts
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Expand Up @@ -177,6 +177,8 @@ export const MODEL_SLUG_ALIASES_BY_PROVIDER: Partial<
"gpt-5.3-spark": "gpt-5.3-codex-spark",
},
[CLAUDE_DRIVER_KIND]: {
"fable-5.1": "claude-fable-5-1",
"claude-fable-5.1": "claude-fable-5-1",
opus: "claude-opus-5",
"opus-5": "claude-opus-5",
"claude-opus-5.0": "claude-opus-5",
Expand Down
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