Key terms for authentication in the AI-native era
ID Token (OIDC)
A JSON Web Token (JWT) issued by an Authorization Server as part of an OIDC flow. It contains claims about the authentication event and the end-user, used by the client to verify the user's identity.
Streaming (A2A)
A mechanism within the A2A protocol (often using Server-Sent Events - SSE) that allows for real-time, incremental updates and progress notifications for long-running tasks between agents.
Behavioral Orchestration
The coordination and sequencing of actions and interactions among multiple agents according to defined protocols and workflows to achieve complex, multi-step objectives.
Agent Ecosystem
A network or environment where various autonomous agents operate, discover each other, and collaborate through standardized protocols like A2A to provide diverse services and capabilities.
Content Modality (A2A)
Refers to the various types of content (text, audio, video, structured data) that agents can exchange and process within the A2A protocol, supporting rich and diverse interactions.
Context Schema
A formal, machine-readable definition that dictates the structure, data types, and relationships of the contextual information exchanged via the MCP, ensuring consistent interpretation by models and agents.
Context Broker
A central or distributed component of the MCP responsible for collecting, aggregating, filtering, and disseminating contextual information to various models and agents based on their subscriptions or queries.
Contextual Data Stream
A continuous flow of real-time or near real-time data elements that contribute to the current context, which models consume through the MCP to make dynamic decisions.
Semantic Context
The process or capability within the MCP to add meaning and relationships to raw data, allowing models to understand the implications of context rather than just the values (e.g., using ontologies or knowledge graphs).
Context Provider
Any entity (e.g., a sensor, another agent, a database, an external system) that generates, monitors, or surfaces specific pieces of information contributing to the overall context managed by the MCP.
Context Consumer
Any model, agent, or application that subscribes to or queries the MCP to receive relevant contextual information necessary for its operation or decision-making.
Contextual Query Language
A specialized language or API provided by the MCP that allows models and agents to precisely request specific pieces of contextual information based on various criteria (e.g., location, time, entity type).
Contextual Event
A discrete, time-stamped notification within the MCP indicating a significant change in the operating environment or a specific context attribute, triggering reactions from subscribing models.
Context Fusion
The process within the MCP of combining contextual information from multiple disparate sources to create a more complete, accurate, or nuanced understanding of the environment for models.
Context Versioning
The ability of the MCP to manage and track different versions of contextual information or context schemas over time, ensuring models can operate with the correct and consistent context.
Context Persistence
The mechanism within the MCP for storing historical or long-term contextual data, allowing models to retrieve past states or analyze trends over time.
Context-Driven Adaptation
The capability enabled by the MCP where models or agents dynamically adjust their behavior, parameters, or strategies based on real-time changes in the contextual information they receive.
Agent Ecosystem
A network or environment where various autonomous agents operate, discover each other, and collaborate through standardized protocols like A2A to provide diverse services and capabilities.
Unique Agent Identity
A persistent, globally unique identifier for the agent.
Credentials
Keys, tokens, or certificates used for authentication (e.g., in Token-Based Authentication) when accessing the Model-Context-Protocol (MCP) or communicating with other agents.
M2M Client Credentials Flow
An OAuth 2.0 authorization grant type specifically designed for machine-to-machine communication where an agent authenticates itself directly to an authorization server using its client ID and secret to obtain an access token.
JWT Claims (Agent Specific)
Key-value pairs embedded within a JWT's payload that carry specific information about the authenticated agent (the subject) and its authorized context, such as its unique ID, assigned roles, capabilities, or specific permissions required for the Model Context Protocol (MCP).
JSON Web Signature (JWS)
A standard (RFC 7515) that defines a compact and URL-safe way to represent the integrity of data (JSON payload) using digital signatures. JWTs typically leverage JWS to ensure their contents have not been tampered with.
JSON Web Encryption (JWE)
A standard (RFC 7516) that defines a compact and URL-safe way to represent encrypted content. While JWTs are often just signed, JWE can be used to additionally encrypt the token's payload to protect sensitive information from unauthorized viewing.
Token Exchange (OAuth)
An OAuth 2.0 extension that allows an agent to exchange one type of security token for another (e.g., exchanging an initial authentication token for a more specific, scoped access token) without re-authenticating the agent's core identity.
Bearer Token
The most common type of access token, where possession of the token itself grants access to a resource. Agents typically include this token in the Authorization: Bearer HTTP header when making API requests.
Client Secret (M2M)
A confidential credential assigned to an agent (acting as an OAuth client), used in conjunction with its client ID to authenticate itself to an authorization server during the M2M Client Credentials Flow. This must be kept highly secure.
JWT Audience (aud) Claim (Agent)
A standard JWT claim that identifies the recipient(s) for whom the JWT is intended. For agents, this would typically be the specific service or resource API that the agent intends to access, ensuring the token is only used by its designated audience.
JWT Issuer (iss) Claim (Agent)
A standard JWT claim that identifies the principal that issued the JWT. For agents accessing a platform, this would be the Identity Provider (IdP) or authorization server that authenticated the agent and minted the token.
Token Lifetime/Expiration (exp Claim)
The duration for which a security token (especially an access token or JWT) remains valid. Agents must be designed to handle token expiry gracefully by requesting new tokens when their current ones near expiration.
JWT Signature Validation
The critical process by which a receiving service (e.g., your MCP or an A2A recipient) verifies the cryptographic signature of a JWT using a public key or shared secret, ensuring the token's authenticity and integrity.
Self-Contained Token
A characteristic of JWTs (and some other token types) meaning that all necessary information for authentication and authorization (claims) is embedded directly within the token itself, reducing the need for database lookups by the relying service.
Refresh Token (Agent)
A special, long-lived token issued by an authorization server to an agent, used exclusively to obtain new, short-lived Access Tokens after the initial access token expires. This allows agents to maintain continuous access to platform resources without requiring repeated re-authentication using the M2M Client Credentials Flow, significantly improving security by limiting the exposure of access tokens.