fix(codemode): validate tool arguments against Zod schema before execution

[tumberger]

Summary

• createCodeTool() extracts .execute functions from tools but discards their Zod schemas, passing them unwrapped to ToolDispatcher
• ToolDispatcher.call() does JSON.parse(argsJson) → fn(args) with no schema validation, so sandboxed code can invoke tool functions with arbitrary JSON payloads that bypass the constraints defined by tool authors
• This patch wraps each extracted execute function with its corresponding Zod schema (inputSchema or parameters) so arguments are validated before reaching the tool function — invalid payloads throw a ZodError caught by the existing error handler

Root cause

In tool.ts:101-111 (before this patch):

for (const [name, t] of Object.entries(tools)) {
  const execute = "execute" in t
    ? (t.execute as (args: unknown) => Promise<unknown>)
    : undefined;
  if (execute) {
    fns[sanitizeToolName(name)] = execute; // ← schema discarded
  }
}

The Zod schemas (t.inputSchema / t.parameters) are available but never extracted. When the sandbox calls a tool via ToolDispatcher.call(), the raw JSON.parse'd payload reaches the tool function directly.

Fix

const schema: ZodType | undefined =
  "inputSchema" in t ? (t.inputSchema as ZodType)
  : "parameters" in t ? ((t as Record<string, unknown>).parameters as ZodType)
  : undefined;

fns[sanitizeToolName(name)] = schema
  ? async (args: unknown) => execute(schema.parse(args))
  : execute;

🤖 Generated with Claude Code

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🦋 Changeset detected

Latest commit: cd015da

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@cloudflare/codemode	Patch

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[mattzcarey]

thanks for this. will look at getting it merged