refactor: Enable makeJsonAgent to be bundled with @endo/bundle-source

This refactors kernel-utils and kernel-errors to enable makeJsonAgent
to be bundled into vats using @endo/bundle-source.

Changes:
- kernel-utils: Added subpath exports (counter, merge-disjoint-records, schema)
- kernel-errors: Added bundleable subpath with simplified error classes
- kernel-errors: Extracted ErrorCode to error-codes.ts (no @metamask/utils dep)
- ocap-kernel: Moved isRetryableNetworkError from kernel-errors to utils
- kernel-agents: Updated to use subpath imports

The bundler was failing due to transitive dependencies on @noble/hashes
which has ESM/CJS compatibility issues. By using subpath exports and
moving libp2p-specific code to ocap-kernel, we avoid pulling in
unbundleable dependencies.

Author: grypez

packages/kernel-agents/src/agent.ts

@@ -1,4 +1,4 @@
-import { mergeDisjointRecords } from '@metamask/kernel-utils';
+import { mergeDisjointRecords } from '@metamask/kernel-utils/merge-disjoint-records';
 import type { Logger } from '@metamask/logger';
 import type { LanguageModel } from '@ocap/kernel-language-model-service';
 

packages/kernel-agents/src/attempt.ts

@@ -1,4 +1,4 @@
-import { SampleGenerationError } from '@metamask/kernel-errors';
+import { SampleGenerationError } from '@metamask/kernel-errors/bundleable';
 import type { Logger } from '@metamask/logger';
 import type { LanguageModel } from '@ocap/kernel-language-model-service';
 

packages/kernel-agents/src/capabilities/discover.ts

@@ -1,5 +1,6 @@
 import { E } from '@endo/eventual-send';
-import type { DiscoverableExo, MethodSchema } from '@metamask/kernel-utils';
+import type { DiscoverableExo } from '@metamask/kernel-utils/discoverable';
+import type { MethodSchema } from '@metamask/kernel-utils/schema';
 
 import type { CapabilityRecord, CapabilitySpec } from '../types.ts';
 

packages/kernel-agents/src/strategies/json/prepare-attempt.ts

@@ -1,4 +1,4 @@
-import { mergeDisjointRecords } from '@metamask/kernel-utils';
+import { mergeDisjointRecords } from '@metamask/kernel-utils/merge-disjoint-records';
 import type { Logger } from '@metamask/logger';
 
 import { makeEvaluator } from './evaluator.ts';

packages/kernel-agents/src/strategies/json/sample-collector.ts

@@ -1,4 +1,4 @@
-import { SampleGenerationError } from '@metamask/kernel-errors';
+import { SampleGenerationError } from '@metamask/kernel-errors/bundleable';
 import type { Logger } from '@metamask/logger';
 
 import type { SampleCollector } from '../../types.ts';

packages/kernel-agents/src/task.ts

@@ -1,4 +1,4 @@
-import { makeCounter } from '@metamask/kernel-utils';
+import { makeCounter } from '@metamask/kernel-utils/counter';
 
 import type { Task, CapabilityRecord } from './types.ts';
 

packages/kernel-agents/src/types/capability.ts

@@ -1,4 +1,4 @@
-import type { JsonSchema } from '@metamask/kernel-utils';
+import type { JsonSchema } from '@metamask/kernel-utils/schema';
 
 export type Capability<Args extends Record<string, unknown>, Return = null> = (
   args: Args,

packages/kernel-errors/package.json

@@ -29,6 +29,16 @@
         "default": "./dist/index.cjs"
       }
     },
+    "./bundleable": {
+      "import": {
+        "types": "./dist/bundleable/index.d.mts",
+        "default": "./dist/bundleable/index.mjs"
+      },
+      "require": {
+        "types": "./dist/bundleable/index.d.cts",
+        "default": "./dist/bundleable/index.cjs"
+      }
+    },
     "./package.json": "./package.json"
   },
   "main": "./dist/index.cjs",
@@ -56,7 +66,6 @@
     "test:watch": "vitest --config vitest.config.ts"
   },
   "dependencies": {
-    "@libp2p/interface": "2.11.0",
     "@metamask/superstruct": "^3.2.1",
     "@metamask/utils": "^11.9.0"
   },

packages/kernel-errors/src/BaseError.ts

@@ -1,6 +1,6 @@
 import type { Json } from '@metamask/utils';
 
-import { ErrorCode } from './constants.ts';
+import { ErrorCode } from './error-codes.ts';
 import type {
   MarshaledOcapError,
   OcapError,

packages/kernel-errors/src/bundleable/SampleGenerationError.ts

@@ -0,0 +1,46 @@
+import { ErrorCode } from '../error-codes.ts';
+
+/**
+ * Error options with optional stack trace.
+ */
+type ErrorOptionsWithStack = {
+  cause?: Error;
+  stack?: string;
+};
+
+/**
+ * Bundleable version of SampleGenerationError.
+ * This version does not include marshaling logic to avoid dependencies
+ * on @metamask/utils that prevent vat bundling.
+ *
+ * An error indicating that the LLM generated invalid response.
+ * This error should trigger resampling from the LLM.
+ */
+export class SampleGenerationError extends Error {
+  public readonly code: typeof ErrorCode.SampleGenerationError;
+
+  public readonly data: { sample: string };
+
+  /**
+   * Creates a new SampleGenerationError.
+   *
+   * @param sample - The invalid sample text generated by the LLM.
+   * @param cause - The underlying error that caused sample generation to fail.
+   * @param options - Additional error options including stack.
+   * @param options.stack - The stack trace of the error.
+   */
+  constructor(sample: string, cause: Error, options?: ErrorOptionsWithStack) {
+    super('LLM generated invalid response.', { cause });
+
+    this.name = 'SampleGenerationError';
+    this.code = ErrorCode.SampleGenerationError;
+    this.data = { sample };
+
+    if (options?.stack) {
+      this.stack = options.stack;
+    }
+
+    harden(this);
+  }
+}
+harden(SampleGenerationError);