What is 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.

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.

It provides the package, authentication, hosting, configuration, and version guidance needed to create an agent that builds and can receive messages.

agents-sdk-dotnet — Skill for Claude Code by microsoft/Agents

About the project

Microsoft 365 Agents SDK is a software toolkit for building AI agents that can communicate through channels such as Microsoft 365 Copilot, Teams, web apps, and custom applications. Developers use it to add state, storage, event handling, and channel-specific behavior while choosing their own AI services and models. The catalogue entries are skills and plugins for working with this SDK.

microsoft/Agents · 1,086 stars · on GitHub · aka.ms

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.

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.

Or install agents-for-dotnet, the plugin that ships this one along with the rest of its 6 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/microsoft/agents/agents-sdk-dotnet/github.svg)](https://agentmods.dev/skills/microsoft/agents/agents-sdk-dotnet)

Your own site

<a href="https://agentmods.dev/skills/microsoft/agents/agents-sdk-dotnet"><img src="https://agentmods.dev/badge/skills/microsoft/agents/agents-sdk-dotnet/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/microsoft/agents/agents-sdk-dotnet"><img src="https://agentmods.dev/badge/skills/microsoft/agents/agents-sdk-dotnet.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

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. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector warn 7 Sept 2026

SkillSpector: 8 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

medium Data Exfiltration · line 320
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium Data Exfiltration · line 61
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium Data Exfiltration · line 113
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium Data Exfiltration · line 122
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium Data Exfiltration · line 149
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium Data Exfiltration · line 166
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium Data Exfiltration · line 325
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
medium Data Exfiltration · line 337
Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.

How audits are shown

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.

Model	Per session	Once invoked
Fable 5.1	$0.00112	$0.05083
Opus 5.5	$0.00045	$0.02033
Sonnet 5.5	$0.00022	$0.01017
Haiku 4.5	$0.00011	$0.00508

Measured 1mo ago against content hash 4a4f4e16df1b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, 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 1mo 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.

1mo 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 (1,086 stars, last pushed yesterday), licensed MIT. It adds 112 tokens to every session and 5,083 once invoked, about $0.0004 per session on Opus 5.5. 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.

Building agents C# and .NET Languages agents bot botframework copilot copilotstudio sdk

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