.NET: Python: Add AGENTS.md files and update coding standards

[eavanvalkenburg]

Summary

This PR adds comprehensive AGENTS.md documentation files for AI coding agents and updates coding standards based on the API review.

Changes

New AGENTS.md Files

• Root python/AGENTS.md - Project overview with links to key docs and all package AGENTS.md files
• Package-level AGENTS.md - Each of the 22 packages now has documentation describing:
  • Package purpose
  • Main classes and their roles
  • Usage examples
  • Import paths

Updated Documentation

• .github/copilot-instructions.md - Improved structure with build/test commands and architecture overview
• python/CODING_STANDARD.md - Added guidance from API review issues:
  • Future annotations convention (#3578)
  • TypeVar naming convention (#3594)
  • Mapping vs MutableMapping (#3577)
  • Avoid shadowing built-ins (#3583)
  • Explicit exports (#3605)
  • Exception documentation guidelines (#3410)
• python/.github/instructions/python.instructions.md - Simplified to reference AGENTS.md

Other

• Removed \AGENTS.md\ from .gitignore to allow tracking

Related Issues

Parent: #3575

cc @eavanvalkenburg

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
TOTAL	16255	1918	88%

report-only-changed-files is enabled. No files were changed during this commit :)

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3929	221 💤	0 ❌	0 🔥	1m 11s ⏱️

[Copilot]

Pull request overview

This PR introduces a unified documentation surface for AI coding agents (AGENTS.md files) across the Python monorepo and updates coding standards and Copilot instructions to align with recent API review decisions.

Changes:

• Added a root python/AGENTS.md and package-level AGENTS.md files for all Python packages to document purposes, main classes, usage, and import paths.
• Updated python/CODING_STANDARD.md with conventions on future annotations, TypeVar naming, mapping types, avoiding built-in shadowing, explicit exports, and exception documentation practices.
• Simplified the Python-specific Copilot instructions to point to AGENTS.md, expanded the repo-wide Copilot instructions with build/test commands and architecture overview, and removed agents.md from .gitignore so these docs are tracked.

Reviewed changes

Copilot reviewed 25 out of 26 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
.github/copilot-instructions.md	Replaced language-specific details with a concise repo-wide overview of structure, build/test commands, and key coding conventions for both Python and .NET.
.gitignore	Removed agents.md from ignore list to allow AGENTS.md documentation files to be committed.
python/.github/instructions/python.instructions.md	Simplified Python Copilot instructions to reference python/AGENTS.md and retain only high-level development guidance.
python/AGENTS.md	Added top-level instructions for AI agents working in the Python repo, including project structure, key conventions, sample structure, and links to all package-level AGENTS.md docs.
python/CODING_STANDARD.md	Documented conventions for from __future__ import annotations, TypeVar naming (*T suffix), preferring Mapping over MutableMapping for non-mutating parameters, avoiding built-in shadowing, explicit __all__ exports, and clarified when and how to document exceptions.
python/packages/core/AGENTS.md	Introduced an overview of the core package layout, key abstractions (agents, clients, types, tools, middleware, threads, memory, workflows), and example usage patterns.
python/packages/a2a/AGENTS.md	Documented the A2A package purpose, A2AAgent class, usage snippet, and supported import paths.
python/packages/ag-ui/AGENTS.md	Described AG-UI integration types (AGUIChatClient, AGUIHttpService, etc.), request/state types, and FastAPI endpoint helper, with usage and import paths.
python/packages/anthropic/AGENTS.md	Documented Anthropic Claude integration (AnthropicClient, AnthropicChatOptions) with usage example and import paths.
python/packages/azure-ai/AGENTS.md	Documented Azure AI Foundry agent integrations (AzureAIAgentClient, AzureAIClient, providers, settings/options) with example usage and imports.
python/packages/azure-ai-search/AGENTS.md	Described Azure AI Search context provider (AzureAISearchContextProvider, AzureAISearchSettings) and how to wire it into a ChatAgent.
python/packages/azurefunctions/AGENTS.md	Documented Azure Functions hosting (AgentFunctionApp) with usage snippet and import paths.
python/packages/bedrock/AGENTS.md	Documented AWS Bedrock integration (BedrockChatClient, options, guardrail config, settings) with example usage and direct import path.
python/packages/chatkit/AGENTS.md	Described ChatKit integration helpers (ThreadItemConverter, stream_agent_response, simple_to_agent_input) with usage and imports.
python/packages/claude/AGENTS.md	Documented Claude Agent SDK integration (ClaudeAgent, options, settings), usage example, and direct import path.
python/packages/copilotstudio/AGENTS.md	Documented Microsoft Copilot Studio agent (CopilotStudioAgent) and acquire_token helper, with example usage and import paths via agent_framework.microsoft and the direct package.
python/packages/declarative/AGENTS.md	Documented declarative agent/workflow support (AgentFactory, WorkflowFactory, WorkflowState, provider mapping, external input types) with usage and import paths.
python/packages/devui/AGENTS.md	Documented DevUI server entry points (serve, DevServer, register_cleanup, CheckpointConversationManager) plus request/response models, CLI usage, and import paths.
python/packages/durabletask/AGENTS.md	Described durable agent support (client/worker types, state and callback abstractions) with example client/worker usage and import paths.
python/packages/foundry_local/AGENTS.md	Documented Azure AI Foundry Local client (FoundryLocalClient, options, settings) with async usage example and direct import path.
python/packages/github_copilot/AGENTS.md	Documented GitHub Copilot agent integration (GitHubCopilotAgent, options, settings), usage example, and imports via agent_framework.github and the direct package.
python/packages/lab/AGENTS.md	Added overview of experimental lab subpackages (GAIA, Lightning, Tau2, namespace) with a note on experimental status and separate installation.
python/packages/mem0/AGENTS.md	Documented Mem0-based context provider (Mem0Provider), usage pattern, import paths, and telemetry behavior (MEM0_TELEMETRY).
python/packages/ollama/AGENTS.md	Documented Ollama client (OllamaChatClient, options, settings) with async usage example and import paths.
python/packages/purview/AGENTS.md	Documented Purview middleware, configuration, caching provider, and exception types, with usage and import examples (note: import path issue called out in review).
python/packages/redis/AGENTS.md	Documented Redis integration (RedisChatMessageStore, RedisProvider), usage example wiring a ChatAgent, and import paths.