How to Integrate Fast.io API with Semantic Kernel Workflows

Why Use Fast.io with Semantic Kernel?

Semantic Kernel orchestrates AI agents, but agents need reliable storage beyond ephemeral memory. Fast.io provides workspaces where agents store files alongside humans.

Key benefits include automatic RAG indexing when intelligence is enabled, multiple uploads, versioning, and multiple MCP tools for advanced integrations.

Unlike S3 or vector DBs, Fast.io handles previews, comments, and shares out of the box. Agents build complete projects and hand them off via one-click transfer.

This integration uses Fast.io's REST API (https://api.fast.io/current/) in SK native plugins. No extra services needed.

Helpful references: Fast.io Workspaces, Fast.io Collaboration, and Fast.io AI.

Practical execution note for Integrate Fast.io API with Semantic Kernel workflows: define a baseline process, assign ownership, and document fallback behavior when dependencies fail. Run a pilot with a small team, collect concrete metrics, and compare throughput, error rate, and review time before broad rollout. After rollout, keep a living checklist so future contributors can repeat the workflow without re-learning critical constraints.

What to check before scaling Integrate Fast.io API with Semantic Kernel workflows

Create a Fast.io account at fast.io. Agent accounts get 50GB storage and 5,000 credits monthly free, no card required.

Install Semantic Kernel NuGets:

dotnet add package Microsoft.SemanticKernel
dotnet add package Microsoft.SemanticKernel.Connectors.OpenAI --prerelease
dotnet add package System.Net.Http.Json

Get an API key from Settings > API Keys. Or use OAuth/JWT for production.

Base URL: https://api.fast.io/current/.

Practical execution note for Integrate Fast.io API with Semantic Kernel workflows: define a baseline process, assign ownership, and document fallback behavior when dependencies fail. Run a pilot with a small team, collect concrete metrics, and compare throughput, error rate, and review time before broad rollout. After rollout, keep a living checklist so future contributors can repeat the workflow without re-learning critical constraints.

Initialize Fast.io Client in Semantic Kernel

Start with a HttpClient configured for Fast.io. Here's the featured snippet code:

1. Create FastIoClient class:

public class FastIoClient
{
  private readonly HttpClient _httpClient;
  private readonly string _apiKey;

public FastIoClient(HttpClient httpClient, string apiKey)
  {
    _httpClient = httpClient;
    _apiKey = apiKey;
    _httpClient.DefaultRequestHeaders.Authorization = new("Bearer", apiKey);
    _httpClient.BaseAddress = new Uri("https://api.fast.io/current/");
  }

// Methods below
}

2. Register in Kernel:

var builder = Kernel.CreateBuilder();
builder.Services.AddSingleton<HttpClient>();
builder.Services.AddSingleton(new FastIoClient(httpClient, apiKey));
var kernel = builder.Build();

This sets up authenticated calls from any plugin function.

Practical execution note for Integrate Fast.io API with Semantic Kernel workflows: define a baseline process, assign ownership, and document fallback behavior when dependencies fail. Run a pilot with a small team, collect concrete metrics, and compare throughput, error rate, and review time before broad rollout. After rollout, keep a living checklist so future contributors can repeat the workflow without re-learning critical constraints.

Build Core Plugin Functions

Define native functions for common operations.

Upload File:

[KernelFunction("UploadFile")]
public async Task<string> UploadFileAsync(string workspaceId, string filePath)
{
  var fileBytes = await File.ReadAllBytesAsync(filePath);
  var content = new MultipartFormDataContent();
  content.Add(new ByteArrayContent(fileBytes), "file", Path.GetFileName(filePath));

var response = await _httpClient.PostAsync($"/workspace/{workspaceId}/upload/single/", content);
  var result = await response.Content.ReadFromJsonAsync<JsonDocument>();
  return result.RootElement.GetProperty("node_id").GetString();
}

List Files:

[KernelFunction("ListFiles")]
public async Task<string> ListFilesAsync(string workspaceId)
{
  var response = await _httpClient.GetAsync($"/workspace/{workspaceId}/storage/root/?limit=50");
  // Parse and return JSON list
  return await response.Content.ReadAsStringAsync();
}

RAG Query (chat_with_files):

[KernelFunction("RagQuery")]
public async Task<string> RagQueryAsync(string workspaceId, string question)
{
  var form = new FormUrlEncodedContent(new[]
  {
    new KeyValuePair<string, string>("type", "chat_with_files"),
    new KeyValuePair<string, string>("query_text", question)
  });
  var response = await _httpClient.PostAsync($"/workspace/{workspaceId}/ai/chat/", form);
  // Poll for complete with message-read
  return await response.Content.ReadAsStringAsync();
}

Practical execution note for Integrate Fast.io API with Semantic Kernel workflows: define a baseline process, assign ownership, and document fallback behavior when dependencies fail. Run a pilot with a small team, collect concrete metrics, and compare throughput, error rate, and review time before broad rollout. After rollout, keep a living checklist so future contributors can repeat the workflow without re-learning critical constraints.

Create Shares and Transfer Ownership

Create Send Share:

[KernelFunction("CreateSendShare")]
public async Task<string> CreateSendShareAsync(string workspaceId)
{
  var form = new FormUrlEncodedContent(new[]
  {
    new KeyValuePair<string, string>("mode", "send"),
    new KeyValuePair<string, string>("storage_mode", "room")
  });
  var response = await _httpClient.PostAsync($"/workspace/{workspaceId}/share/", form);
  var result = await response.Content.ReadFromJsonAsync<JsonDocument>();
  return $"https://go.fast.io/shared/{result.GetProperty("custom_name").GetString()}/{result.GetProperty("title_slug").GetString()}";
}

Transfer Org Ownership:

[KernelFunction("TransferOwnership")]
public async Task<string> TransferOwnershipAsync(string orgId)
{
  var response = await _httpClient.PostAsync($"/org/{orgId}/transfer/token/create/");
  var result = await response.Content.ReadFromJsonAsync<JsonDocument>();
  var token = result.GetProperty("token").GetString();
  return $"https://go.fast.io/claim?token={token}";
}

Share the claim URL with humans for smooth handoff.

Practical execution note for Integrate Fast.io API with Semantic Kernel workflows: define a baseline process, assign ownership, and document fallback behavior when dependencies fail. Run a pilot with a small team, collect concrete metrics, and compare throughput, error rate, and review time before broad rollout. After rollout, keep a living checklist so future contributors can repeat the workflow without re-learning critical constraints.

Full Workflow Example

Orchestrate in a SK agent:

var uploadResult = await kernel.InvokeAsync<string>("UploadFile", new() { ["workspaceId"] = wsId, ["filePath"] = "report.pdf" });
var ragResult = await kernel.InvokeAsync<string>("RagQuery", new() { ["workspaceId"] = wsId, ["question"] = "Summarize key findings" });
var shareUrl = await kernel.InvokeAsync<string>("CreateSendShare", new() { ["workspaceId"] = wsId });
var claimUrl = await kernel.InvokeAsync<string>("TransferOwnership", new() { ["orgId"] = orgId });

return $"Report uploaded. Summary: {ragResult}. Share: {shareUrl}. Claim: {claimUrl}";

This builds, analyzes, shares, and hands off a complete project.

Add one practical example, one implementation constraint, and one measurable outcome so the section is concrete and useful for execution.

Teams should validate this approach in a small test path first, then standardize it across environments once metrics and outcomes are stable.