| ABP | Agentic Browser Protocol |
| ABP Manifest | JSON file describing an app’s ABP support and capabilities |
| ABP Runtime | App-side implementation exposed on window.abp |
| ABP Client | Any agent-side implementation for interacting with ABP apps |
| AbortSignal | Web standard for signaling cancellation, used by ABP for cancel support |
| Agent | AI system or CLI tool consuming ABP capabilities |
| App | Web application implementing ABP |
| Base64 | Binary-to-text encoding used for binary data over WebSocket transport |
| BinaryData | Wrapper object for binary content with mimeType, encoding, and size metadata |
| BinaryDataReference | Reference to large binary content via downloadUrl instead of inline data |
| Call ID | Unique identifier for a capability call, used for cancellation |
| Cancellation | Aborting an in-progress operation before completion |
| Capability | Browser feature exposed through ABP |
| Call | Execute a capability (equivalent to MCP’s tools/call) |
| Contract | The interface definition (manifest + window.abp) that ABP specifies, independent of any client implementation |
| Discovery | Process of determining if an app supports ABP and what it offers |
| Elicitation | App requesting input from agent (equivalent to MCP’s elicitation) |
| Headful Mode | Browser launched with a visible window, required for full ABP capability access |
| Manifest Link | HTML <link rel="abp-manifest"> tag pointing to the manifest |
| MCP Bridge | Recommended client architecture: a generic MCP server that translates ABP capabilities into MCP tools for AI agents |
| Notification | One-way message from app to agent |
| Session | Active connection between agent and app |
| Transfer List | postMessage feature for zero-copy ArrayBuffer transfer |
| Transport | Communication layer (Puppeteer, postMessage, WebSocket) used by a client implementation |