agents-sdk-dotnet

A reference guide for building and configuring Microsoft 365 Agents SDK agents in C# or .NET. The SDK is Microsoft's toolkit for agents that can work across Teams, Copilot Studio, and web chat.

In plain words
What is it for?
Use it when setting up an Agents SDK project, configuring ASP.NET Core hosting and Microsoft Entra authentication, handling agent state, or choosing the required packages and Azure resources.
Why use it?
It provides the package, authentication, hosting, configuration, and version guidance needed to create an agent that builds and can receive messages.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/microsoft/agents/agents-sdk-dotnet
Any agent
npx skills add microsoft/Agents --skill agents-sdk-dotnet
Clone the repo
git clone --depth 1 https://github.com/microsoft/Agents

Made for: Claude Code, Codex.

Per session 112 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,083 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00112 $0.05083
Opus 5 $0.00056 $0.02542
Sonnet 5 $0.00022 $0.01017
Haiku 4.5 $0.00011 $0.00508

Measured 2d ago against content hash 4a4f4e16df1b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agents-sdk-dotnet scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s -X POST \
agent-plugins/agents-for-net/skills/agents-sdk-dotnet/SKILL.md · 770 lines

How it starts

The opening of the file, as written. The whole thing — 770 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Overview

The Microsoft 365 Agents SDK builds multichannel agents for Teams, Copilot Studio, and web chat.

Package Purpose
Microsoft.Agents.Hosting.AspNetCore ASP.NET Core hosting, auth, endpoint mapping
Microsoft.Agents.Authentication.Msal MSAL-based auth (client credentials, OBO)
Microsoft.Agents.Builder Core: AgentApplication, ITurnContext, ITurnState
Microsoft.Agents.Core Models, activity types, channel accounts
Microsoft.Agents.Storage IStorage, MemoryStorage
Microsoft.Agents.Extensions.Teams Teams-specific models and extensions
Microsoft.Agents.Builder.Dialogs Dialog system (waterfall, prompts)
Microsoft.Agents.AI AI-specific features

Minimal project requires only: Microsoft.Agents.Hosting.AspNetCore + Microsoft.Agents.Authentication.Msal. The others are transitive dependencies pulled in automatically.

Always use the latest non-beta (stable) version. Do not use --prerelease unless specifically needed.

Requires .NET 8+.

Azure Resources Required

Microsoft Entra App Registration

  • ClientId — Application (client) ID
  • ClientSecret — Certificates & secrets
  • TenantId — Directory (tenant) ID

Azure Bot Resource

  • Messaging endpoint: https://<your-host>/api/messages
  • Microsoft App ID must match ClientId

Local dev: Set TokenValidation:Enabled to false. No Azure Bot needed until deployment.

Configuration (appsettings.json)

Single connection (most common)

appsettings.json — no secret here (safe to commit):

{
  "Connections": {
    "ServiceConnection": {
      "Settings": {
        "AuthType": "ClientSecret",
        "AuthorityEndpoint": "https://login.microsoftonline.com/<tenantId>",
        "ClientId": "<appId>",
        "Scopes": ["https://api.botframework.com/.default"]
      }
    }
  },
  "ConnectionsMap": [
    {
      "ServiceUrl": "*",
      "Connection": "ServiceConnection"
    }
  ],
  "TokenValidation": {
    "Enabled": true,
    "Audiences": ["<appId>"],
    "TenantId": "<tenantId>"
  }
}

Read the full file on GitHub · 770 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 770 lines · 112 tokens per session scan A 4a4f4e16df1b

Subscribe to this mod's changes

agents-sdk-dotnet is a skill published in the GitHub repository microsoft/Agents (1,050 stars, last pushed 5d ago), licensed MIT. It adds 112 tokens to every session and 5,083 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories

azure-kusto-graph

Build and query Kusto graphs from natural language. Covers transient graphs (make-graph), persistent graph models/snapshots, pattern matching (graph-match), shortest paths, connected components, and graph-to-table export. Generates the edges-first thinking: define edges, define node lookups, union, make-graph. WHEN…

microsoft/skills · 131 tokens

azure-kusto-irql-graph

Apply IRQL graph functions to KQL or IRQL query results for Kusto Explorer visualization. Generates LiftToGraph mappings and composes GraphRenderView, GraphFoldByProperty, ExtractNode, EnrichNode, and EnrichGraph calls. Accepts a supplied query or limited basic natural-language source request; it is not a general…

microsoft/skills · 155 tokens

azure-maps-search-dotnet

Azure Maps SDK for .NET. Location-based services including geocoding, routing, rendering, geolocation, and weather. Use for address search, directions, map tiles, IP geolocation, and weather data. Triggers: "Azure Maps", "MapsSearchClient", "MapsRoutingClient", "MapsRenderingClient", "geocoding .NET", "route…

microsoft/skills · 91 tokens

azure-mgmt-applicationinsights-dotnet

Azure Application Insights SDK for .NET. Application performance monitoring and observability resource management. Use for creating Application Insights components, web tests, workbooks, analytics items, and API keys. Triggers: "Application Insights", "ApplicationInsights", "App Insights", "APM", "application…

microsoft/skills · 82 tokens

azure-resource-manager-postgresql-dotnet

Azure PostgreSQL Flexible Server SDK for .NET. Database management for PostgreSQL Flexible Server deployments. Use for creating servers, databases, firewall rules, configurations, backups, and high availability. Triggers: "PostgreSQL", "PostgreSqlFlexibleServer", "PostgreSQL Flexible Server", "Azure Database for…

microsoft/skills · 97 tokens

azure-ai-agents-persistent-dotnet

Azure AI Agents Persistent SDK for .NET. Low-level SDK for creating and managing AI agents with threads, messages, runs, and tools. Use for agent CRUD, conversation threads, streaming responses, function calling, file search, and code interpreter. Triggers: "PersistentAgentsClient", "persistent agents", "agent…

microsoft/skills · 90 tokens