@juspay/neurolink/dist/utils/mcpErrorText.js

The pipe layer of an AI nervous system: one interface connecting provider neurons to your application, across three inference types — generate, stream and decide. `decide` returns typed, calibrated judgements from a non-generative model (~400ms, ~$0.00002

/**
 * Extract a human-readable error string from an MCP isError result object.
 *
 * Shared utility — no side effects, no dependencies on other SDK modules —
 * so it can be imported from the neurolink.ts event loop, the telemetry
 * instrumentation (which loads earlier), and the MCP discovery layer without
 * creating circular imports. Any change to truncation or content-type parsing
 * must happen here and propagate to all three surfaces.
 */
export function extractMcpErrorText(raw) {
    let resultObj;
    try {
        resultObj = typeof raw === "string" ? JSON.parse(raw) : raw;
    }
    catch {
        return "";
    }
    if (!resultObj || typeof resultObj !== "object") {
        return "";
    }
    const content = resultObj.content;
    if (!Array.isArray(content)) {
        return "";
    }
    // Fail closed on malformed entries (e.g. `content: [null]`) rather than
    // throwing — the caller expects an empty string for unparseable input.
    const texts = content
        .filter((c) => c !== null &&
        typeof c === "object" &&
        c.type === "text" &&
        typeof c.text === "string" &&
        c.text.length > 0)
        .map((c) => c.text);
    return texts.join(" ").substring(0, 500);
}
/**
 * MCP tools signal failure by RETURNING `{ isError: true, ... }`, not throwing,
 * so execute()'s try/catch never sees it. Returns a capped status message for
 * failures (undefined for success) for the caller to set the span error level.
 *
 * Generic over input shape: accepts either a result object or a JSON-stringified
 * envelope (different providers hand back different shapes), mirroring
 * `extractMcpErrorText`. A non-JSON string has no `isError` field, so it is
 * correctly treated as "not an error" (→ undefined).
 *
 * Layered on `extractMcpErrorText`: this adds the `isError === true` gate and
 * the human-readable "MCP tool returned isError: …" prefix, while the shared
 * helper owns the content parsing and the 500-char cap. When `isError` is set
 * but no readable text is present, falls back to a generic message.
 */
export function extractMcpToolErrorMessage(result) {
    let resultObj = result;
    if (typeof resultObj === "string") {
        try {
            resultObj = JSON.parse(resultObj);
        }
        catch {
            return undefined;
        }
    }
    if (!resultObj || typeof resultObj !== "object") {
        return undefined;
    }
    if (resultObj.isError !== true) {
        return undefined;
    }
    const text = extractMcpErrorText(resultObj);
    return text
        ? `MCP tool returned isError: ${text}`
        : "MCP tool returned isError: true";
}
/**
 * Detect a tool result that REPORTS failure without throwing, for the native
 * loops' consecutive-failure breaker. Covers the two shapes NeuroLink itself
 * produces or forwards:
 * - MCP CallToolResult with `isError: true` (e.g. proxy-blocked tools) —
 *   delegated to {@link extractMcpToolErrorMessage}
 * - our own `{ error: "..." }` payloads
 * Plain strings are never classified (too false-positive-prone).
 * Returns the error text, or null when the result looks like a success.
 */
export function extractToolFailureText(result) {
    const mcpError = extractMcpToolErrorMessage(result);
    if (mcpError) {
        return mcpError;
    }
    if (result !== null &&
        typeof result === "object" &&
        typeof result.error === "string" &&
        result.error.length > 0) {
        return result.error;
    }
    return null;
}