azure-active-directory-b2c

# Azure Active Directory B2C Skill

This skill provides expert guidance for Azure Active Directory B2C. Covers troubleshooting, best practices, decision making, architecture & design patterns, limits & quotas, security, configuration, integrations & coding patterns, and deployment. It combines local quick-reference content with remote documentation fetching capabilities.

## How to Use This Skill

> **IMPORTANT for Agent**: Use the **Category Index** below to locate relevant sections. For categories with line ranges (e.g., `L35-L120`), use `read_file` with the specified lines. For categories with file links (e.g., `[security.md](security.md)`), use `read_file` on the linked reference file

> **IMPORTANT for Agent**: If `metadata.generated_at` is more than 3 months old, suggest the user pull the latest version from the repository. If `mcp_microsoftdocs` tools are not available, suggest the user install it: [Installation Guide](https://github.com/MicrosoftDocs/mcp/blob/main/README.md)

This skill requires **network access** to fetch documentation content:
- **Preferred**: Use `mcp_microsoftdocs:microsoft_docs_fetch` with query string `from=learn-agent-skill`. Returns Markdown.
- **Fallback**: Use `fetch_webpage` with query string `from=learn-agent-skill&accept=text/markdown`. Returns Markdown.

## Category Index

| Category | Lines | Description |
|----------|-------|-------------|
| Troubleshooting | L37-L43 | Diagnosing and fixing Azure AD B2C errors, debugging custom policies and user flows, and using Application Insights to trace and troubleshoot policy execution. |
| Best Practices | L44-L52 | Best practices for configuring Azure AD B2C, designing user flows/custom policies, securing MFA and architecture, and detecting/mitigating credential and account attacks. |
| Decision Making | L53-L61 | Guidance on planning Azure AD B2C usage: choosing app types, understanding MAU billing, regions/data residency, retirement impact, and selecting a user migration strategy. |
| Architecture & Design Patterns | L62-L70 | Global Azure AD B2C customer identity architectures, comparing funnel- vs region-based designs, and step-by-step proof-of-concept implementations for each pattern |
| Limits & Quotas | L71-L78 | Service limits, quotas, and restrictions for Azure AD B2C tenants, including directory size, token formats/constraints, and tenant creation and scaling limits. |
| Security | L79-L95 | Security hardening for Azure AD B2C: MFA, Conditional Access, Identity Protection, CAPTCHA, TLS/ciphers, policy keys, admin/tenant access control, API security, and Sentinel-based monitoring. |
| Configuration | L96-L210 | Configuring Azure AD B2C: custom policies, user flows, tokens, MFA, identity providers, claims/transformations, app/API registration, UI/localization, SSO, security, and advanced auth options. |
| Integrations & Coding Patterns | L211-L323 | Patterns and step-by-step guides for integrating Azure AD B2C into apps, securing APIs, configuring IdPs/social logins, custom policies, fraud/risk tools, and routing logs/monitoring. |
| Deployment | L324-L328 | Automating deployment of Azure AD B2C custom policies using CI/CD pipelines, including setup steps, YAML examples, and best practices for Azure Pipelines and GitHub Actions. |

### Troubleshooting
| Topic | URL |
|-------|-----|
| Azure AD B2C error codes and troubleshooting reference | https://learn.microsoft.com/en-us/azure/active-directory-b2c/error-codes |
| Troubleshoot Azure AD B2C custom policies and user flows | https://learn.microsoft.com/en-us/azure/active-directory-b2c/troubleshoot |
| Troubleshoot Azure AD B2C custom policies with Application Insights | https://learn.microsoft.com/en-us/azure/active-directory-b2c/troubleshoot-with-application-insights |

### Best Practices
| Topic | URL |
|-------|-----|
| Apply Azure AD B2C integration and configuration best practices | https://learn.microsoft.com/en-us/azure/active-directory-b2c/best-practices |
| Developer guidance for Azure AD B2C user flows and custom policies | https://learn.microsoft.com/en-us/azure/active-directory-b2c/custom-policy-developer-notes |
| Secure phone-based MFA in Azure AD B2C using monitoring and alerts | https://learn.microsoft.com/en-us/azure/active-directory-b2c/phone-based-mfa |
| Apply security best practices to Azure AD B2C architecture | https://learn.microsoft.com/en-us/azure/active-directory-b2c/security-architecture |
| Mitigate credential attacks in Azure AD B2C | https://learn.microsoft.com/en-us/azure/active-directory-b2c/threat-management |

### Decision Making
| Topic | URL |
|-------|-----|
| Choose appropriate application types for Azure AD B2C | https://learn.microsoft.com/en-us/azure/active-directory-b2c/application-types |
| Understand Azure AD B2C MAU billing and tier selection | https://learn.microsoft.com/en-us/azure/active-directory-b2c/billing |
| Plan Azure AD B2C region availability and data residency | https://learn.microsoft.com/en-us/azure/active-directory-b2c/data-residency |
| Plan Azure AD B2C usage and retirement impact | https://learn.microsoft.com/en-us/azure/active-directory-b2c/faq |
| Choose a user migration approach to Azure AD B2C | https://learn.microsoft.com/en-us/azure/active-directory-b2c/user-migration |

### Architecture & Design Patterns
| Topic | URL |
|-------|-----|
| Apply funnel-based global identity design with Azure AD B2C | https://learn.microsoft.com/en-us/azure/active-directory-b2c/b2c-global-identity-funnel-based-design |
| Implement funnel-based global identity proof of concept in Azure AD B2C | https://learn.microsoft.com/en-us/azure/active-directory-b2c/b2c-global-identity-proof-of-concept-funnel |
| Implement region-based global identity proof of concept in Azure AD B2C | https://learn.microsoft.com/en-us/azure/active-directory-b2c/b2c-global-identity-proof-of-concept-regional |
| Apply region-based global identity design with Azure AD B2C | https://learn.microsoft.com/en-us/azure/active-directory-