[Naveen Chatlapalli (1aifanatic)]

Motivation & Context

Six .NET sample READMEs end their environment variable setup with "If the variables are not set, you will be prompted for the values when running the samples." None of these samples prompt. Each reads its settings with GetEnvironmentVariable(...) ?? throw new InvalidOperationException(...) and stops. The only Console.ReadLine calls in these folders are for chat input and tool approvals.

Description & Review Guide

• What are the major changes? Replace the sentence with "If a required variable is not set, the sample stops with an error that names the missing variable." in:
  • 02-agents/Agents/README.md
  • 02-agents/A2A/README.md
  • 02-agents/AgentProviders/README.md
  • 02-agents/AgentProviders/anthropic/README.md
  • 02-agents/ModelContextProtocol/README.md
  • 02-agents/AgentWithRAG/AgentWithRAG_Step02_CustomVectorStoreRAG/README.md
• What is the impact of these changes? Documentation only.
• What do you want reviewers to focus on? Nothing special.

I checked that every throw on a missing variable in these folders names the variable (for example FOUNDRY_PROJECT_ENDPOINT is not set., Please set the GOOGLE_GENAI_API_KEY environment variable.). The ModelContextProtocol edit is 10 lines below the line #9581 changes, so the two do not conflict.

Related Issue

N/A - trivial change: the READMEs describe a prompt that the samples do not implement, and the actual behavior is unambiguous from the code.

AI Assistance

• No material AI assistance was used.
• This is an AI-assisted contribution. I reviewed, understood, and verified all submitted content and accept responsibility for it.

AI assistance details: Claude Code helped compare the README claims with the samples' code, make the edits, and draft this description.

Contribution Checklist

• The code builds clean without any errors or warnings
• All unit tests pass, and I have added new tests where possible
• The PR follows the Contribution Guidelines
• This PR links to an agreed issue with no competing open PR, or the Related Issue section documents a trivial-change or repository-automation exception.
• This is not a breaking change. If it is a breaking change, add the breaking change label (or add "[BREAKING]" to the title prefix, before or after any language prefix) — a workflow keeps the label and title prefix in sync automatically.

🤖 Generated with Claude Code

[Copilot]

🟢 Approval recommended

The six documentation-only corrections match the reported sample validation behavior, with no unresolved findings.

No open issues 🎉

What changed in this PR

Corrects six .NET sample READMEs to describe existing behavior when required environment variables are missing.

Changes:

• Removes incorrect claims that samples prompt for missing values.
• Clarifies that samples stop with an error naming the missing variable.
• Changes documentation only; runtime behavior is unchanged.

File	Description
dotnet/​samples/​02-agents/​ModelContextProtocol/​README.md	Corrects missing-variable guidance for MCP samples.
dotnet/​samples/​02-agents/​AgentWithRAG/​AgentWithRAG_Step02_CustomVectorStoreRAG/​README.md	Corrects missing-variable guidance for custom vector-store RAG.
dotnet/​samples/​02-agents/​Agents/​README.md	Corrects missing-variable guidance for agent samples.
dotnet/​samples/​02-agents/​AgentProviders/​README.md	Corrects shared provider setup guidance.
dotnet/​samples/​02-agents/​AgentProviders/​anthropic/​README.md	Corrects missing-variable guidance for Anthropic samples.
dotnet/​samples/​02-agents/​A2A/​README.md	Corrects missing-variable guidance for A2A samples.

_{Review effort: Balanced}