authentication-learn

name	authentication-learn
source	botcore
description	Guides authentication and authorization design for web applications, APIs, and AI agent systems. Covers OAuth 2.1, OIDC, passkeys/WebAuthn, RBAC/ABAC/ReBAC, Cedar policy language, session management (JWT vs server sessions), multi-tenant patterns, zero trust continuous verification, MCP server auth, and agentic identity with machine-to-machine delegation. Use when designing login flows, implementing authorization, adding passkeys, configuring SSO, building multi-tenant auth, securing MCP servers, or managing AI agent credentials. Triggers: authentication, authorization, OAuth, OIDC, passkey, WebAuthn, RBAC, ABAC, session, JWT, token, multi-tenant, SSO, MFA, zero trust, MCP auth, agent identity, delegation.
version	1.0.0
triggers	["authentication","authorization","OAuth","OIDC","passkey","WebAuthn","RBAC","ABAC","ReBAC","session management","JWT","token rotation","multi-tenant","SSO","SAML","MFA","zero trust","MCP auth","agent identity","delegation","Cedar policy","access control"]
portable	true

Handling Authentication

Expert guidance for designing and implementing authentication, authorization, and identity management across web apps, APIs, multi-tenant SaaS, and AI agent systems.

Capabilities

1. OAuth 2.1 and OIDC -- Authorization code + PKCE, client credentials, DPoP sender-constrained tokens, and OpenID Connect identity layer
2. Passkeys and WebAuthn -- Passwordless authentication with progressive rollout, conditional UI, and phishing resistance
3. Authorization Models -- RBAC, ABAC, ReBAC design and Cedar/*BAC policy language for unified access control
4. Session Management -- JWT vs server sessions, hybrid approaches, token rotation, secure cookies
5. Multi-Tenant Authentication -- Tenant discovery, per-tenant policies, SSO integration, data isolation
6. Agentic Authentication -- AI agent identity, MCP server OAuth, delegation chains, scope attenuation, machine-to-machine tokens
7. Zero Trust Patterns -- Continuous verification, device trust, step-up authentication, behavioral analysis

Routing Logic

Request type	Load reference
OAuth 2.1, OIDC, PKCE, DPoP, grant types, token endpoints	references/oauth-and-oidc.md
Passkeys, WebAuthn, passwordless, FIDO2, conditional UI	references/passkeys-and-webauthn.md
RBAC, ABAC, ReBAC, Cedar, OPA, Zanzibar, policy engines	references/authorization-models.md
JWT, sessions, cookies, token rotation, token lifetimes	references/session-management.md
Multi-tenant, tenant discovery, SSO, SAML, per-tenant config	references/multi-tenant-auth.md
AI agent auth, MCP OAuth, delegation, M2M, agent identity	references/agentic-auth.md
Zero trust, continuous verification, device trust, step-up	references/zero-trust-patterns.md

Core Principles

1. Defense in Depth

Never rely on a single authentication factor or authorization check. Layer protections:

• Authentication: passkey > password + MFA > password alone
• Authorization: enforce at API gateway, service layer, and data layer
• Sessions: short-lived access tokens + rotated refresh tokens + server-side revocation

2. Least Privilege by Default

Grant minimum permissions for minimum time:

// Bad: Over-broad, long-lived token
scope: 'admin:full', expiresIn: '30d'

// Good: Minimal scope, short-lived
scope: 'read:documents', expiresIn: '15m'

• Request scopes incrementally as features need them
• AI agents get task-specific scopes, never admin access
• Refresh tokens rotate on each use
• Default-deny in all authorization policies

3. Cryptographic Proof over Shared Secrets

Prefer mechanisms where secrets are never transmitted:

Prefer	Over
Passkeys (public key crypto)	Passwords (shared secret)
DPoP (sender-constrained tokens)	Bearer tokens
PKCE (code challenge)	Implicit flow
private_key_jwt client auth	Client secret in request body

4. Tokens Must Be Bound and Short-Lived

• Access tokens: 15 minutes maximum
• Refresh tokens: 7-14 days with rotation
• Include audience (aud), issuer (iss), and tenant (tid) claims
• Bind to sender where possible (DPoP, mTLS)
• Never store tokens in localStorage; use httpOnly cookies or secure storage

5. Every Action Must Be Attributable

All authentication and authorization events must trace to a responsible identity:

• Human users: user ID + session ID + auth method
• AI agents: agent ID + human sponsor + delegation chain
• Log: who, what, when, from where, with what permissions, allow/deny decision

6. Multi-Tenant Isolation Is Non-Negotiable

• Every token includes tenant context (tid claim)
• Data queries always scoped by tenant (Row-Level Security)
• Auth policies are per-tenant, not global
• Cross-tenant access is an immediate security incident

Quick Reference

OAuth 2.1 Grant Types

Grant	Use Case	Client Type
Authorization Code + PKCE	User login (web, mobile, SPA)	Public or confidential
Client Credentials	Machine-to-machine, AI agents	Confidential
Device Authorization	CLI tools, TVs, IoT	Public
Token Exchange (RFC 8693)	Delegation, on-behalf-of	Confidential

Authentication Method Strength

Method	Phishing Resistant	Recommended
Passkey (WebAuthn)	Yes	Primary for users
Hardware security key	Yes	Backup/recovery
TOTP authenticator app	No	MFA secondary factor
Password + MFA	No	Legacy, migrate away
Password only	No	Not recommended
SMS OTP	No	Avoid for sensitive apps
Static API key	N/A	Avoid; use OAuth tokens

Token Lifetimes

Token	Lifetime	Notes
Access token (JWT)	15 min	Short-lived, stateless validation
Refresh token	7-14 days	Rotate on each use
ID token	1 hour	Identity assertion only
Agent access token	5-15 min	Even shorter for autonomous agents
Session (server)	30 days sliding	Extended with activity

Authorization Model Selection

Need simple role hierarchy?           -> RBAC
Need attribute-based conditions?      -> ABAC
Need resource ownership/sharing?      -> ReBAC
Need all of the above unified?        -> Cedar / *BAC

Workflow

Authentication Design Protocol

1. Assess Requirements

• Identify user types (human, service, AI agent)
• Determine tenant model (single, multi-tenant, B2B)
• List authentication methods needed (password, passkey, SSO, M2M)
• Identify compliance requirements (SOC 2, HIPAA, PCI DSS)
• Map sensitive operations that need step-up auth

2. Design Authentication Flow

• Choose primary auth method (passkeys recommended for users)
• Design MFA strategy (TOTP, WebAuthn for second factor)
• Plan session management (hybrid JWT + server sessions recommended)
• Configure token lifetimes and rotation strategy
• Design account recovery flow (avoid SMS-based recovery with passkeys)

3. Design Authorization Model

• Choose model (RBAC for simple, Cedar for complex)
• Define roles, permissions, and resource types
• Implement default-deny with explicit grants
• Enforce at API gateway, service layer, and data layer
• Plan for authorization audit logging

4. Implement Multi-Tenant (if applicable)

• Choose tenant discovery pattern (subdomain, email, invite)
• Implement per-tenant auth policies
• Configure enterprise SSO (SAML/OIDC) per tenant
• Enforce data isolation (RLS, schema, or DB separation)
• Scope all tokens with tenant ID

5. Implement Agent Auth (if applicable)

• Register agent identities with unique client IDs
• Use OAuth 2.1 client credentials or token exchange
• Implement delegation chains with scope attenuation
• Set up MCP server OAuth with resource indicators
• Ensure all agent actions trace to human sponsor
• Automate credential rotation

6. Apply Zero Trust

• Implement continuous trust evaluation (not just login-time)
• Add device posture checking for sensitive operations
• Configure step-up auth for trust degradation
• Classify resources by sensitivity tier
• Set up behavioral anomaly detection

Agentic Workflow Considerations

When an AI agent is implementing authentication:

1. Never hardcode secrets -- Use environment variables or vault references
2. Generate secure random values -- Use crypto.randomBytes() or equivalent, never Math.random()
3. Validate all tokens server-side -- Never trust client-provided claims without verification
4. Test for common vulnerabilities -- CSRF, session fixation, token leakage in logs
5. Document auth decisions -- Explain why a particular pattern was chosen
6. Flag for human review -- Authentication code changes should always be reviewed by a human

Checklist

Authentication

• OAuth 2.1 flows use PKCE (no implicit or password grants)
• Passkeys offered as primary authentication method
• MFA enforced for sensitive operations at minimum
• Passwords hashed with Argon2id, bcrypt, or scrypt (never MD5/SHA)
• Rate limiting on authentication endpoints
• Account lockout after repeated failures (with unlock mechanism)
• Brute-force protection on all auth endpoints

Sessions and Tokens

• Access tokens expire in 15 minutes or less
• Refresh tokens rotate on each use with reuse detection
• JWTs signed with RS256/ES256 (asymmetric) for distributed systems
• JWT alg: none explicitly rejected in validation
• Cookies set: httpOnly, secure, sameSite, scoped path
• Session regenerated after login (session fixation prevention)
• Logout revokes server-side session and clears all cookies

Authorization

• Default-deny policy (no access unless explicitly granted)
• Authorization enforced server-side at service and data layers
• No client-side-only authorization checks
• Resource access verified per-request (no cached permissions stale > 5 min)
• Audit log captures every allow/deny decision

Multi-Tenant

• Tenant ID present in every token and validated on every request
• Data isolation enforced at database level (RLS or schema separation)
• Cross-tenant token reuse impossible (audience + tenant validation)
• Per-tenant SSO and MFA policies supported

Agent Identity

• Each agent has a unique identity (no shared service accounts)
• Agent tokens are short-lived (5-15 minutes) with auto-rotation
• Delegation chain preserved in tokens (traceable to human sponsor)
• Scope attenuation enforced (sub-agents cannot exceed parent permissions)
• MCP servers validate tokens with resource indicators

When to Escalate

• Authentication bypass suspected -- Any path that skips authentication checks
• Cross-tenant data access -- Token or query returning data from another tenant
• Privilege escalation -- User or agent gaining permissions beyond their grant
• Credential leakage -- Tokens, keys, or secrets appearing in logs, URLs, or client code
• Cryptographic decisions -- Custom crypto, algorithm selection, key management design
• Compliance-driven requirements -- SOC 2, HIPAA, PCI DSS, FedRAMP auth requirements
• Agent permission model design -- First-time setup of agent identity and delegation infrastructure
• SSO integration issues -- SAML/OIDC federation with enterprise identity providers
• Recovery flow design -- Account recovery mechanisms that could weaken authentication guarantees