Function stripProviderPrefix

src/model-utils.ts:82–96

* Strip a leading provider segment that Bedrock (and similar) prepend before * the actual family token — e.g. `anthropic.`, `us.anthropic.`, `eu.`. Keeps * everything from the recognised family token onward so prefix matching works.

(id: string)

 * everything from the recognised family token onward so prefix matching works.
 */
function stripProviderPrefix(id: string): string {
  // Remove leading region/provider segments (dot-separated) until we hit the
  // model token. Provider/region segments never contain a hyphen, whereas
  // model families do (e.g. `claude-3-5-sonnet`, `gpt-4.1`). So drop any
  // leading dot-separated segment that has no hyphen.
  let rest = id;
  while (true) {
    const dot = rest.indexOf(".");
    if (dot === -1) break;
    const head = rest.slice(0, dot);
    if (head.length === 0 || head.includes("-")) break;
    rest = rest.slice(dot + 1);
  }
  return rest;
}

// Normalize each comma-separated env entry IDENTICALLY to the incoming model id
// (date-suffix + provider/region prefix stripped, lowercased) so a prefixed