Function buildPiModel

packages/core/src/agent.ts:264–324

(
  model: ModelRef,
  wire: WireApi | undefined,
  baseUrl: string | undefined,
  httpHeaders?: Record<string, string> | undefined,
  apiKey?: string,
)

};

function buildPiModel(
  model: ModelRef,
  wire: WireApi | undefined,
  baseUrl: string | undefined,
  httpHeaders?: Record<string, string> | undefined,
  apiKey?: string,
): PiModel {
  // Fall through to the canonical public endpoint for the 3 first-party
  // BYOK providers when the caller omitted baseUrl. This is a fact about
  // those endpoints (api.anthropic.com is anthropic), not a registry lookup for a
  // model registry — imported / custom providers still require baseUrl and
  // will throw if absent.
  const resolvedBaseUrl =
    baseUrl && baseUrl.trim().length > 0
      ? baseUrl
      : (BUILTIN_PUBLIC_BASE_URLS[model.provider] ?? '');
  if (resolvedBaseUrl.length === 0) {
    throw new CodesignError(
      `Provider "${model.provider}" has no baseUrl configured. Add one in Settings or re-import the config.`,
      ERROR_CODES.PROVIDER_BASE_URL_MISSING,
    );
  }
  // Defensive: canonicalize stored baseUrl before handing to pi-ai. Rescues
  // legacy configs that persisted pre-normalization (e.g. raw `/v1/chat/completions`
  // pasted in an older build). No-op for configs saved post-fix.
  // For openai-codex-responses, canonicalBaseUrl only strips trailing slashes
  // — pi-ai's codex wire appends `/codex/responses` from the bare base itself.
  const canonicalBase = wire ? canonicalBaseUrl(resolvedBaseUrl, wire) : resolvedBaseUrl;
  const effectiveModelId = normalizeGeminiModelId(model.modelId, canonicalBase);
  const out: PiModel = {
    id: effectiveModelId,
    name: effectiveModelId,
    api: apiForWire(wire),
    provider: model.provider,
    baseUrl: canonicalBase,
    reasoning: inferReasoning(wire, effectiveModelId, canonicalBase),
    input: supportsImageInput(wire, effectiveModelId) ? ['text', 'image'] : ['text'],
    cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
    contextWindow: 200000,
    maxTokens: 32000,
  };
  const compat = openAIChatCompatForBaseUrl(wire, canonicalBase);
  if (compat !== undefined) out.compat = compat;
  if (httpHeaders !== undefined) out.headers = httpHeaders;

  // sub2api / claude2api gateways 403 any request without claude-cli
  // identity headers. pi-ai only emits them for sk-ant-oat OAuth tokens —
  // so a custom anthropic baseUrl keyed by a plain token hits the edge WAF.
  // Inject them here too (this path goes through pi-agent-core, which
  // forwards model.headers to pi-ai). User-supplied headers keep precedence.
  // Skip when the key already looks OAuth-shaped: pi-ai's OAuth branch
  // injects the same set, and leaving that the single source keeps us from
  // silently overriding future pi-ai header updates on the OAuth path.
  if (
    shouldForceClaudeCodeIdentity(wire, canonicalBase) &&
    (apiKey === undefined || !looksLikeClaudeOAuthToken(apiKey))
  ) {
    out.headers = { ...claudeCodeIdentityHeaders(), ...(out.headers ?? {}) };