diff --git a/packages/sdk/test/schemas-package-contract.test.ts b/packages/sdk/test/schemas-package-contract.test.ts
new file mode 100644
index 0000000000..74f99fa660
--- /dev/null
+++ b/packages/sdk/test/schemas-package-contract.test.ts
@@ -0,0 +1,136 @@
+import assert from 'node:assert/strict'
+import fs from 'node:fs'
+import path from 'node:path'
+import { fileURLToPath } from 'node:url'
+import { describe, it } from 'node:test'
+
+type SchemaObject = {
+  shape?: Record<string, { description?: unknown }>
+}
+
+type JsonSchema = {
+  properties?: Record<string, JsonSchema>
+  [key: string]: unknown
+}
+
+const packageRoot = fileURLToPath(new URL('..', import.meta.url))
+const packageJson = JSON.parse(fs.readFileSync(path.join(packageRoot, 'package.json'), 'utf8')) as {
+  name: string
+  exports: Record<string, unknown>
+}
+
+function readJson(filePath: string): JsonSchema {
+  return JSON.parse(fs.readFileSync(filePath, 'utf8')) as JsonSchema
+}
+
+function findObjectProperties(
+  node: unknown,
+  fieldNames: readonly string[]
+): Array<Record<string, JsonSchema>> {
+  if (node === null || typeof node !== 'object') return []
+
+  const matches: Array<Record<string, JsonSchema>> = []
+  const properties = (node as JsonSchema).properties
+  if (
+    properties &&
+    Object.keys(properties).length === fieldNames.length &&
+    fieldNames.every((fieldName) => fieldName in properties)
+  ) {
+    matches.push(properties)
+  }
+
+  for (const value of Object.values(node as Record<string, unknown>)) {
+    matches.push(...findObjectProperties(value, fieldNames))
+  }
+  return matches
+}
+
+function assertDescribedFields(label: string, schema: SchemaObject): string[] {
+  const fields = schema.shape ?? {}
+  const fieldNames = Object.keys(fields)
+  assert.ok(fieldNames.length > 0, `${label} should expose object fields`)
+
+  for (const fieldName of fieldNames) {
+    assert.equal(
+      typeof fields[fieldName]?.description,
+      'string',
+      `${label}.${fieldName} should retain its public description`
+    )
+    assert.ok(
+      (fields[fieldName]?.description as string).trim().length > 0,
+      `${label}.${fieldName} should not have an empty description`
+    )
+  }
+  return fieldNames
+}
+
+describe('@qvac/sdk 0.18 schemas package contract', () => {
+  it('keeps the schemas subpath mapped to built runtime and declaration files', () => {
+    const schemasExport = packageJson.exports['./schemas']
+    assert.deepEqual(schemasExport, {
+      types: './dist/src/schemas/public.d.ts',
+      import: './dist/src/schemas/public.js',
+      require: './dist/src/schemas/public.js'
+    })
+
+    for (const target of Object.values(schemasExport as Record<string, string>)) {
+      assert.ok(
+        fs.existsSync(path.join(packageRoot, target)),
+        `package export target should exist after build: ${target}`
+      )
+    }
+
+    const declarations = fs.readFileSync(
+      path.join(packageRoot, 'dist/src/schemas/public.d.ts'),
+      'utf8'
+    )
+    for (const name of [
+      'llamacppCompletionConfigSchema',
+      'llamacppEmbeddingConfigSchema',
+      'modelSourceSchema',
+      'LlamacppCompletionConfig',
+      'LlamacppEmbeddingConfig',
+      'ModelSource'
+    ]) {
+      assert.match(declarations, new RegExp(`\\b${name}\\b`), `${name} should be typed publicly`)
+    }
+  })
+
+  it('exposes the documented aliases from the installed package subpath', async () => {
+    const publicSchemas = (await import(`${packageJson.name}/schemas`)) as Record<string, unknown>
+    assert.deepEqual(Object.keys(publicSchemas).sort(), [
+      'llamacppCompletionConfigSchema',
+      'llamacppEmbeddingConfigSchema',
+      'modelSourceSchema'
+    ])
+
+    const completion = publicSchemas.llamacppCompletionConfigSchema as SchemaObject
+    const embedding = publicSchemas.llamacppEmbeddingConfigSchema as SchemaObject
+    const modelSource = publicSchemas.modelSourceSchema as {
+      safeParse: (value: unknown) => { success: boolean }
+    }
+    const completionFields = assertDescribedFields('llamacppCompletionConfigSchema', completion)
+    const embeddingFields = assertDescribedFields('llamacppEmbeddingConfigSchema', embedding)
+
+    assert.equal(modelSource.safeParse('models/example.gguf').success, true)
+    assert.equal(modelSource.safeParse({ src: 'models/example.gguf' }).success, true)
+
+    const contract = readJson(path.join(packageRoot, 'contract', 'schema.json'))
+    for (const [label, fields] of [
+      ['completion', completionFields],
+      ['embedding', embeddingFields]
+    ] as const) {
+      const matches = findObjectProperties(contract, fields)
+      assert.ok(matches.length > 0, `contract/schema.json should contain the ${label} config`)
+      for (const properties of matches) {
+        for (const fieldName of fields) {
+          assert.equal(
+            properties[fieldName]?.description,
+            (label === 'completion' ? completion : embedding).shape?.[fieldName]?.description,
+            `contract description should match the public ${label} schema for ${fieldName}`
+          )
+        }
+      }
+    }
+  })
+})