Walrus MCP Server

Instructions

Implementation Reference

• src/index.ts:153-164 (handler)

  MCP tool handler for 'get_blob': parses arguments with GetBlobSchema and calls walrusClient.getBlob, returning the result as text content

  case 'get_blob': {
    const { blobId } = GetBlobSchema.parse(args);
    const result = await walrusClient.getBlob(blobId);
    return {
      content: [
        {
          type: 'text',
          text: result,
        },
      ],
    };
  }

• src/index.ts:35-37 (schema)

  Zod input schema validation for the get_blob tool (requires blobId string)

  const GetBlobSchema = z.object({
    blobId: z.string().describe('The blob ID to retrieve'),
  });

• src/index.ts:74-87 (registration)

  Tool registration descriptor for 'get_blob' in the ListTools response, defining name, description, and input schema

  {
    name: 'get_blob',
    description: 'Retrieve a blob from Walrus storage',
    inputSchema: {
      type: 'object',
      properties: {
        blobId: {
          type: 'string',
          description: 'The blob ID to retrieve',
        },
      },
      required: ['blobId'],
    },
  },

• src/walrus-client.ts:106-126 (helper)

  Core implementation of blob retrieval in WalrusClient: HTTP GET to aggregator, returns base64-encoded blob data with error handling

  async getBlob(blobId: string): Promise<string> {
    try {
      const response = await this.httpClient.get(
        `${this.config.aggregatorUrl}/v1/${blobId}`,
        {
          responseType: 'arraybuffer',
        }
      );
  
      // Return as base64 encoded string
      return Buffer.from(response.data).toString('base64');
    } catch (error) {
      if (axios.isAxiosError(error)) {
        if (error.response?.status === 404) {
          throw new Error(`Blob not found: ${blobId}`);
        }
        throw new Error(`Failed to retrieve blob: ${error.response?.data?.error || error.message}`);
      }
      throw new Error(`Failed to retrieve blob: ${error instanceof Error ? error.message : String(error)}`);
    }
  }