Merge pull request #1483 from anomalyco/add-extends-support

feat: add extends support

Author: rekram1-node

AGENTS.md

@@ -31,9 +31,27 @@
 ## Model Configuration
 
 - Model `id` is **auto-injected** from filename (minus `.toml`) — never put `id` in TOML files
-- Same model is duplicated across provider directories with no cross-referencing
+- Models may reuse another model's definition via `extends` (see below); otherwise the full definition must be present in the file
 - Schema uses `.strict()` — extra fields cause validation errors
 
+### `[extends]` (inheritance between models)
+- Syntax — a table at the top of the TOML:
+  ```toml
+  [extends]
+  from = "<provider-id>/<model-id>"   # required
+  omit = ["experimental.modes.fast"]  # optional, dot-path strings
+  ```
+  Example: `from = "anthropic/claude-opus-4-6"`
+- Resolved at parse time in `generate()`; the final JSON output contains **no** `extends` field — it exists only to cut duplication in the TOMLs
+- Merge semantics:
+  - Plain objects (`[cost]`, `[limit]`, `[modalities]`, `[provider]`, `[experimental]`, …) are **deep-merged**
+  - Arrays (e.g. `modalities.input`) and primitives are **replaced** wholesale by the child
+  - Any field the child omits is inherited verbatim from the base
+- `omit` runs **after** the merge and deletes each dot-path from the result (used when the child needs to *remove* something the base defines, e.g. a provider-specific experimental mode). Every listed path must exist in the merged model, else an error is thrown. Ancestor tables that become empty as a result are also pruned, so `omit = ["experimental.modes.fast"]` yields no `experimental` key in the final JSON when `fast` was the only mode.
+- Chains are allowed (A extends B extends C); cycles throw
+- The base model must exist; `[extends.from]` pointing at a missing provider/model is an error
+- The `extends` table is stripped before schema validation, so the merged result must still satisfy the strict `Model` schema
+
 ### Bedrock Naming Patterns
 - Dated models: `-v1:0` suffix (`anthropic.claude-3-5-sonnet-20241022-v1:0.toml`)
 - Latest/undated models: bare `-v1` (`anthropic.claude-opus-4-6-v1.toml`)

bun.lock

@@ -16,6 +16,7 @@
   },
   "scripts": {
     "validate": "bun ./packages/core/script/validate.ts",
+    "compare:migrations": "bun ./packages/core/script/compare-model-migrations.ts",
     "helicone:generate": "bun ./packages/core/script/generate-helicone.ts",
     "venice:generate": "bun ./packages/core/script/generate-venice.ts",
     "vercel:generate": "bun ./packages/core/script/generate-vercel.ts",

package.json

@@ -4,6 +4,7 @@
   "$schema": "https://json.schemastore.org/package.json",
   "type": "module",
   "dependencies": {
+    "remeda": "^2.33.7",
     "zod": "catalog:"
   },
   "main": "./src/index.ts",

packages/core/package.json

@@ -0,0 +1,89 @@
+#!/usr/bin/env bun
+
+import path from "node:path";
+import { cp, mkdir, rm, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { generate } from "../src/generate.js";
+
+const root = path.join(import.meta.dirname, "..", "..", "..");
+const providersPath = path.join(root, "providers");
+
+const diffOutput = await Bun.$`git diff --name-only HEAD -- providers`.cwd(root).text();
+const changedProviderPaths = diffOutput
+  .split("\n")
+  .filter(Boolean)
+  .filter((filePath) => /^providers\/[^/]+\/models\/.+\.toml$/.test(filePath));
+
+if (changedProviderPaths.length === 0) {
+  process.exit(0);
+}
+
+const baselineRoot = path.join(tmpdir(), `models-dev-compare-${Date.now()}`);
+await mkdir(baselineRoot, { recursive: true });
+
+try {
+  const baselineProvidersPath = path.join(baselineRoot, "providers");
+  await cp(providersPath, baselineProvidersPath, { recursive: true });
+
+  for (const filePath of changedProviderPaths) {
+    const tempFilePath = path.join(baselineRoot, filePath);
+    const show = Bun.spawn(["git", "show", `HEAD:${filePath}`], {
+      cwd: root,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    const exitCode = await show.exited;
+    if (exitCode !== 0) {
+      await rm(tempFilePath, { force: true });
+      continue;
+    }
+
+    const contents = await new Response(show.stdout).text();
+    await mkdir(path.dirname(tempFilePath), { recursive: true });
+    await writeFile(tempFilePath, contents);
+  }
+
+  const before = await generate(baselineProvidersPath);
+  const after = await generate(providersPath);
+
+  for (const filePath of changedProviderPaths) {
+    const match = /^providers\/([^/]+)\/models\/(.+)\.toml$/.exec(filePath);
+    if (!match) continue;
+
+    const [, providerID, modelID] = match;
+    const beforeModel = before[providerID]?.models[modelID];
+    const afterModel = after[providerID]?.models[modelID];
+    const beforeJson = JSON.stringify(beforeModel, null, 2);
+    const afterJson = JSON.stringify(afterModel, null, 2);
+
+    if (beforeJson === afterJson) {
+      continue;
+    }
+
+    const beforeFilePath = path.join(baselineRoot, "before.json");
+    const afterFilePath = path.join(baselineRoot, "after.json");
+    await writeFile(beforeFilePath, `${beforeJson}\n`);
+    await writeFile(afterFilePath, `${afterJson}\n`);
+
+    const diff = Bun.spawn(
+      [
+        "diff",
+        "-u",
+        "-L",
+        `${filePath} (before)`,
+        "-L",
+        `${filePath} (after)`,
+        beforeFilePath,
+        afterFilePath,
+      ],
+      {
+        stdout: "pipe",
+        stderr: "pipe",
+      },
+    );
+    const output = await new Response(diff.stdout).text();
+    process.stdout.write(output);
+  }
+} finally {
+  await rm(baselineRoot, { recursive: true, force: true });
+}

packages/core/script/compare-model-migrations.ts

@@ -1,9 +1,31 @@
 import path from "path";
+import { mergeDeep } from "remeda";
+import { z } from "zod";
 
 import { Provider, Model } from "./schema.js";
 
+const ExtendsModel = Model.sourceType()
+  .partial()
+  .extend({
+    extends: z
+      .object({
+        from: z
+          .string()
+          .regex(/^[^/]+\/[^/]+$/, "Must be in provider/model format"),
+        omit: z.array(z.string()).optional(),
+      })
+      .strict(),
+  })
+  .strict();
+
 export async function generate(directory: string) {
-  const result = {} as Record<string, Provider>;
+  const result: Record<string, Provider> = {};
+  const extendsModels: Array<{
+    providerID: string;
+    modelID: string;
+    modelPath: string;
+    model: z.infer<typeof ExtendsModel>;
+  }> = [];
   for await (const providerPath of new Bun.Glob("*/provider.toml").scan({
     cwd: directory,
     absolute: true,
@@ -35,6 +57,20 @@ export async function generate(directory: string) {
         },
       }).then((mod) => mod.default);
       toml.id = modelID;
+      if (toml.extends !== undefined) {
+        const model = ExtendsModel.safeParse(toml);
+        if (!model.success) {
+          model.error.cause = { modelPath, toml };
+          throw model.error;
+        }
+        extendsModels.push({
+          providerID,
+          modelID,
+          modelPath,
+          model: model.data,
+        });
+        continue;
+      }
       const model = Model.safeParse(toml);
       if (!model.success) {
         model.error.cause = { modelPath, toml };
@@ -45,5 +81,77 @@ export async function generate(directory: string) {
     result[providerID] = provider.data;
   }
 
+  for (const pendingModel of extendsModels) {
+    const [providerID, modelID] = pendingModel.model.extends.from.split("/");
+    const baseModel = result[providerID]?.models[modelID];
+    if (baseModel === undefined) {
+      throw new Error(`Unable to resolve extends.from: ${pendingModel.model.extends.from}`, {
+        cause: { modelPath: pendingModel.modelPath, toml: pendingModel.model },
+      });
+    }
+
+    const { extends: extendsConfig, ...overrides } = pendingModel.model;
+    const merged: Record<string, unknown> = structuredClone(
+      mergeDeep(baseModel, overrides),
+    );
+
+    for (const omit of extendsConfig.omit ?? []) {
+      const parts = omit.split(".");
+      const parents: Array<{
+        value: Record<string, unknown>;
+        key: string;
+      }> = [];
+      let current = merged;
+
+      for (const part of parts.slice(0, -1)) {
+        const next = current[part];
+        if (
+          next === undefined ||
+          next === null ||
+          typeof next !== "object" ||
+          Array.isArray(next)
+        ) {
+          throw new Error(`Unable to omit missing path: ${omit}`, {
+            cause: { modelPath: pendingModel.modelPath, toml: pendingModel.model },
+          });
+        }
+        parents.push({ value: current, key: part });
+        current = next as Record<string, unknown>;
+      }
+
+      const lastPart = parts.at(-1);
+      if (lastPart === undefined || !(lastPart in current)) {
+        throw new Error(`Unable to omit missing path: ${omit}`, {
+          cause: { modelPath: pendingModel.modelPath, toml: pendingModel.model },
+        });
+      }
+
+      delete current[lastPart];
+
+      for (let index = parents.length - 1; index >= 0; index--) {
+        const parent = parents[index];
+        const value = parent?.value[parent.key];
+        if (
+          value === null ||
+          value === undefined ||
+          typeof value !== "object" ||
+          Array.isArray(value) ||
+          Object.keys(value).length > 0
+        ) {
+          break;
+        }
+        delete parent.value[parent.key];
+      }
+    }
+
+    const model = Model.safeParse(merged);
+    if (!model.success) {
+      model.error.cause = { modelPath: pendingModel.modelPath, toml: merged };
+      throw model.error;
+    }
+
+    result[pendingModel.providerID]!.models[pendingModel.modelID] = model.data;
+  }
+
   return result;
 }

packages/core/src/generate.ts

@@ -1,24 +1,2 @@
-name = "Claude Haiku 3.5"
-family = "claude-haiku"
-release_date = "2024-10-22"
-last_updated = "2024-10-22"
-attachment = true
-reasoning = false
-temperature = true
-knowledge = "2024-07"
-tool_call = true
-open_weights = false
-
-[cost]
-input = 0.80
-output = 4.00
-cache_read = 0.08
-cache_write = 1.00
-
-[limit]
-context = 200_000
-output = 8_192
-
-[modalities]
-input = ["text", "image", "pdf"]
-output = ["text"]
+[extends]
+from = "anthropic/claude-3-5-haiku-20241022"

providers/amazon-bedrock/models/anthropic.claude-3-5-haiku-20241022-v1:0.toml

@@ -1,25 +1,5 @@
-name = "Claude Opus 4.6"
-family = "claude-opus"
-release_date = "2026-02-05"
-last_updated = "2026-03-18"
-attachment = true
-reasoning = true
-temperature = true
-tool_call = true
 structured_output = true
-knowledge = "2025-05-31"
-open_weights = false
 
-[cost]
-input = 5.00
-output = 25.00
-cache_read = 0.50
-cache_write = 6.25
-
-[limit]
-context = 1_000_000
-output = 128_000
-
-[modalities]
-input = ["text", "image", "pdf"]
-output = ["text"]
+[extends]
+from = "anthropic/claude-opus-4-6"
+omit = ["experimental.modes.fast"]

providers/amazon-bedrock/models/anthropic.claude-opus-4-6-v1.toml

@@ -1,25 +1,6 @@
 name = "Claude Opus 4.6 (EU)"
-family = "claude-opus"
-release_date = "2026-02-05"
-last_updated = "2026-03-18"
-attachment = true
-reasoning = true
-temperature = true
-tool_call = true
 structured_output = true
-knowledge = "2025-05-31"
-open_weights = false
 
-[cost]
-input = 5.00
-output = 25.00
-cache_read = 0.50
-cache_write = 6.25
-
-[limit]
-context = 1_000_000
-output = 128_000
-
-[modalities]
-input = ["text", "image", "pdf"]
-output = ["text"]
+[extends]
+from = "anthropic/claude-opus-4-6"
+omit = ["experimental.modes.fast"]

providers/amazon-bedrock/models/eu.anthropic.claude-opus-4-6-v1.toml

@@ -1,25 +1,6 @@
 name = "Claude Opus 4.6 (Global)"
-family = "claude-opus"
-release_date = "2026-02-05"
-last_updated = "2026-03-18"
-attachment = true
-reasoning = true
-temperature = true
-tool_call = true
 structured_output = true
-knowledge = "2025-05-31"
-open_weights = false
 
-[cost]
-input = 5.00
-output = 25.00
-cache_read = 0.50
-cache_write = 6.25
-
-[limit]
-context = 1_000_000
-output = 128_000
-
-[modalities]
-input = ["text", "image", "pdf"]
-output = ["text"]
+[extends]
+from = "anthropic/claude-opus-4-6"
+omit = ["experimental.modes.fast"]