lithtrix_blob_download

Instructions

Implementation Reference

• tools/blobs.js:194-217 (registration)

  Registration of the lithtrix_blob_download tool on the MCP server using server.tool(). Calls blobDownloadResult() helper on success.

  server.tool(
    "lithtrix_blob_download",
    "Download blob bytes (GET /v1/blobs/{blob_id}). Returns JSON with content_base64 and content_type. " +
      "Requires LITHTRIX_API_KEY.",
    { blob_id: blobIdSchema },
    async ({ blob_id }) => {
      const apiKey = process.env.LITHTRIX_API_KEY;
      if (!apiKey) return missingApiKeyResponse();
  
      const path = `/v1/blobs/${encodeURIComponent(blob_id)}`;
      let response;
      try {
        response = await fetch(new URL(path, LITHTRIX_API_URL), {
          headers: {
            Authorization: `Bearer ${apiKey}`,
            Accept: "*/*",
          },
        });
      } catch (err) {
        return networkErrorResponse(err);
      }
      return blobDownloadResult(response);
    }
  );

• tools/blobs.js:198-198 (schema)

  Input schema: blob_id (string, length 19, regex /^b_[0-9a-f]{16}$/) validated via blobIdSchema.

  { blob_id: blobIdSchema },

• tools/blobs.js:199-216 (handler)

  Handler function: checks LITHTRIX_API_KEY, GETs /v1/blobs/{blob_id}, returns blobDownloadResult(response).

  async ({ blob_id }) => {
    const apiKey = process.env.LITHTRIX_API_KEY;
    if (!apiKey) return missingApiKeyResponse();
  
    const path = `/v1/blobs/${encodeURIComponent(blob_id)}`;
    let response;
    try {
      response = await fetch(new URL(path, LITHTRIX_API_URL), {
        headers: {
          Authorization: `Bearer ${apiKey}`,
          Accept: "*/*",
        },
      });
    } catch (err) {
      return networkErrorResponse(err);
    }
    return blobDownloadResult(response);
  }

• tools/blobs.js:75-117 (helper)

  Helper function blobDownloadResult() that reads the response as arrayBuffer, encodes to base64, extracts content-type, and returns JSON with content_base64, content_type, size_bytes.

  async function blobDownloadResult(response) {
    if (!response.ok) {
      let body;
      try {
        body = await response.json();
      } catch {
        body = {};
      }
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify({
              error: body.message ?? `Lithtrix API error (HTTP ${response.status})`,
              error_code: body.error_code ?? "UNKNOWN",
              status: body.status,
            }),
          },
        ],
        isError: true,
      };
    }
  
    const buf = await response.arrayBuffer();
    const b64 = Buffer.from(buf).toString("base64");
    const ct = response.headers.get("content-type") || "application/octet-stream";
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(
            {
              content_base64: b64,
              content_type: ct,
              size_bytes: buf.byteLength,
            },
            null,
            2
          ),
        },
      ],
    };
  }

• tools/blobs.js:10-14 (helper)

  blobIdSchema — Zod schema validating blob_id format (length 19, prefix b_ + 16 hex chars).

  const blobIdSchema = z
    .string()
    .length(19)
    .regex(/^b_[0-9a-f]{16}$/)
    .describe("Content-addressed blob id (b_ + 16 hex chars)");