Crate agent_client_protocol_schema

Expand description

§Agent Client Protocol Schema

Strongly-typed Rust definitions of the Agent Client Protocol (ACP) wire format. ACP is a JSON-RPC based protocol that standardizes communication between code editors (IDEs, text-editors, etc.) and coding agents (programs that use generative AI to autonomously modify code).

This crate is only the schema: the request, response, and notification types, plus serde plumbing and JSON Schema generation. For the runtime pieces (transport, connection setup, the Agent / Client traits, etc.) use the higher-level agent-client-protocol crate, which builds on top of these types.

§What’s in this crate

Wire-format types for every ACP method: request, response, and notification structs grouped by which side handles them.
JSON-RPC envelope and routing types: JsonRpcMessage, rpc::JsonRpcBatch, Request, Response, Notification, RequestId, Error.
Aggregated routing enums: AgentRequest, AgentResponse, AgentNotification, and the matching client-side trio used by SDK crates to dispatch incoming JSON-RPC messages.
The generate binary that emits the published schema.json, meta.json, and the accompanying mdx documentation consumed by the protocol website and registry.

§Versioning

The default surface re-exports the v1 (current stable) protocol types directly at the crate root, so most consumers can write agent_client_protocol_schema::SessionId (and so on) without thinking about versions.

For the complete protocol specification and documentation, visit https://agentclientprotocol.com.

Re-exports§

pub use crate::rpc::JsonRpcMessage;
pub use crate::rpc::Notification;
pub use crate::rpc::Request;
pub use crate::rpc::RequestId;

Modules§

rpc
v2unstable_protocol_v2: Agent Client Protocol version 2 draft types.

Structs§

AcceptNesNotificationunstable_nes: Notification sent when a suggestion is accepted.
AgentAuthCapabilities: Authentication-related capabilities supported by the agent.
AgentCapabilities: Capabilities supported by the agent.
AgentMethodNames: Names of all methods that agents handle.
Annotations: Optional annotations for the client. The client can use annotations to inform how objects are used or displayed
AudioContent: Audio provided to or from an LLM.
AuthCapabilities: UNSTABLE
AuthEnvVar: UNSTABLE
AuthMethodAgent: Agent handles authentication itself.
AuthMethodEnvVar: UNSTABLE
AuthMethodId
AuthMethodTerminal: UNSTABLE
AuthenticateRequest: Request parameters for the authenticate method.
AuthenticateResponse: Response to the authenticate method.
AvailableCommand: Information about a command.
AvailableCommandsUpdate: Available commands are ready or have changed
BlobResourceContents: Binary resource contents.
BooleanPropertySchemaunstable_elicitation: Schema for boolean properties in an elicitation form.
CancelNotification: Notification to cancel ongoing operations for a session.
CancelRequestNotificationunstable_cancel_request: UNSTABLE
ClientCapabilities: Capabilities supported by the client.
ClientMethodNames: Names of all methods that clients handle.
ClientNesCapabilitiesunstable_nes: NES capabilities advertised by the client during initialization.
CloseNesRequestunstable_nes: Request to close an NES session.
CloseNesResponseunstable_nes: Response from closing an NES session.
CloseSessionRequest: Request parameters for closing an active session.
CloseSessionResponse: Response from closing a session.
CompleteElicitationNotificationunstable_elicitation: UNSTABLE
ConfigOptionUpdate: Session configuration options have been updated.
ConnectMcpRequestunstable_mcp_over_acp: UNSTABLE
ConnectMcpResponseunstable_mcp_over_acp: UNSTABLE
Content: Standard content block (text, images, resources).
ContentChunk: A streamed item of content
Cost: Cost information for a session.
CreateElicitationRequestunstable_elicitation: UNSTABLE
CreateElicitationResponseunstable_elicitation: UNSTABLE
CreateTerminalRequest: Request to create a new terminal and execute a command.
CreateTerminalResponse: Response containing the ID of the created terminal.
CurrentModeUpdate: The current mode of the session has changed
DeleteSessionRequest: Request parameters for deleting an existing session from session/list.
DeleteSessionResponse: Response from deleting a session.
DidChangeDocumentNotificationunstable_nes: Notification sent when a file is edited.
DidCloseDocumentNotificationunstable_nes: Notification sent when a file is closed.
DidFocusDocumentNotificationunstable_nes: Notification sent when a file becomes the active editor tab.
DidOpenDocumentNotificationunstable_nes: Notification sent when a file is opened in the editor.
DidSaveDocumentNotificationunstable_nes: Notification sent when a file is saved.
Diff: A diff representing file modifications.
DisableProviderRequest: UNSTABLE
DisableProviderResponse: UNSTABLE
DisconnectMcpRequestunstable_mcp_over_acp: UNSTABLE
DisconnectMcpResponseunstable_mcp_over_acp: UNSTABLE
ElicitationAcceptActionunstable_elicitation: UNSTABLE
ElicitationCapabilitiesunstable_elicitation: UNSTABLE
ElicitationFormCapabilitiesunstable_elicitation: UNSTABLE
ElicitationFormModeunstable_elicitation: UNSTABLE
ElicitationIdunstable_elicitation: UNSTABLE
ElicitationRequestScopeunstable_elicitation: UNSTABLE
ElicitationSchemaunstable_elicitation: Type-safe elicitation schema for requesting structured user input.
ElicitationSessionScopeunstable_elicitation: UNSTABLE
ElicitationUrlCapabilitiesunstable_elicitation: UNSTABLE
ElicitationUrlModeunstable_elicitation: UNSTABLE
EmbeddedResource: The contents of a resource, embedded into a prompt or tool call result.
EnumOptionunstable_elicitation: A titled enum option with a const value and human-readable title.
EnvVariable: An environment variable to set when launching an MCP server.
Error: JSON-RPC error object.
ExtNotification: Allows the Agent to send an arbitrary notification that is not part of the ACP spec. Extension notifications provide a way to send one-way messages for custom functionality while maintaining protocol compatibility.
ExtRequest: Allows for sending an arbitrary request that is not part of the ACP spec. Extension methods provide a way to add custom functionality while maintaining protocol compatibility.
ExtResponse: Allows for sending an arbitrary response to an ExtRequest that is not part of the ACP spec. Extension methods provide a way to add custom functionality while maintaining protocol compatibility.
FileSystemCapabilities: File system capabilities that a client may support.
ForkSessionRequest: UNSTABLE
ForkSessionResponse: UNSTABLE
GeneralMethodNamesunstable_cancel_request: Names of all methods that agents handle.
HttpHeader: An HTTP header to set when making requests to the MCP server.
ImageContent: An image provided to or from an LLM.
Implementation: Metadata about the implementation of the client or agent. Describes the name and version of an MCP implementation, with an optional title for UI representation.
InitializeRequest: Request parameters for the initialize method.
InitializeResponse: Response to the initialize method.
IntegerPropertySchemaunstable_elicitation: Schema for integer properties in an elicitation form.
KillTerminalRequest: Request to kill a terminal without releasing it.
KillTerminalResponse: Response to terminal/kill method
ListProvidersRequest: UNSTABLE
ListProvidersResponse: UNSTABLE
ListSessionsRequest: Request parameters for listing existing sessions.
ListSessionsResponse: Response from listing sessions.
LoadSessionRequest: Request parameters for loading an existing session.
LoadSessionResponse: Response from loading an existing session.
LogoutCapabilities: Logout capabilities supported by the agent.
LogoutRequest: Request parameters for the logout method.
LogoutResponse: Response to the logout method.
McpCapabilities: MCP capabilities supported by the agent
McpConnectionIdunstable_mcp_over_acp: UNSTABLE
McpServerAcp: UNSTABLE
McpServerAcpIdunstable_mcp_over_acp: UNSTABLE
McpServerHttp: HTTP transport configuration for MCP.
McpServerSse: SSE transport configuration for MCP.
McpServerStdio: Stdio transport configuration for MCP.
MessageId: Unique identifier for a message within a session.
MessageMcpNotificationunstable_mcp_over_acp: UNSTABLE
MessageMcpRequestunstable_mcp_over_acp: UNSTABLE
MessageMcpResponseunstable_mcp_over_acp: UNSTABLE
MultiSelectPropertySchemaunstable_elicitation: Schema for multi-select (array) properties in an elicitation form.
NesCapabilitiesunstable_nes: NES capabilities advertised by the agent during initialization.
NesContextCapabilitiesunstable_nes: Context capabilities the agent wants attached to each suggestion request.
NesDiagnosticunstable_nes: A diagnostic (error, warning, etc.).
NesDiagnosticsCapabilitiesunstable_nes: Capabilities for diagnostics context.
NesDocumentDidChangeCapabilitiesunstable_nes: Capabilities for document/didChange events.
NesDocumentDidCloseCapabilitiesunstable_nes: Marker for document/didClose capability support.
NesDocumentDidFocusCapabilitiesunstable_nes: Marker for document/didFocus capability support.
NesDocumentDidOpenCapabilitiesunstable_nes: Marker for document/didOpen capability support.
NesDocumentDidSaveCapabilitiesunstable_nes: Marker for document/didSave capability support.
NesDocumentEventCapabilitiesunstable_nes: Document event capabilities the agent wants to receive.
NesEditHistoryCapabilitiesunstable_nes: Capabilities for edit history context.
NesEditHistoryEntryunstable_nes: An entry in the edit history.
NesEditSuggestionunstable_nes: A text edit suggestion.
NesEventCapabilitiesunstable_nes: Event capabilities the agent can consume.
NesExcerptunstable_nes: A code excerpt from a file.
NesJumpCapabilitiesunstable_nes: Marker for jump suggestion support.
NesJumpSuggestionunstable_nes: A jump-to-location suggestion.
NesOpenFileunstable_nes: An open file in the editor.
NesOpenFilesCapabilitiesunstable_nes: Capabilities for open files context.
NesRecentFileunstable_nes: A recently accessed file.
NesRecentFilesCapabilitiesunstable_nes: Capabilities for recent files context.
NesRelatedSnippetunstable_nes: A related code snippet from a file.
NesRelatedSnippetsCapabilitiesunstable_nes: Capabilities for related snippets context.
NesRenameCapabilitiesunstable_nes: Marker for rename suggestion support.
NesRenameSuggestionunstable_nes: A rename symbol suggestion.
NesRepositoryunstable_nes: Repository metadata for an NES session.
NesSearchAndReplaceCapabilitiesunstable_nes: Marker for search and replace suggestion support.
NesSearchAndReplaceSuggestionunstable_nes: A search-and-replace suggestion.
NesSuggestContextunstable_nes: Context attached to a suggestion request.
NesTextEditunstable_nes: A text edit within a suggestion.
NesUserActionunstable_nes: A user action (typing, cursor movement, etc.).
NesUserActionsCapabilitiesunstable_nes: Capabilities for user actions context.
NewSessionRequest: Request parameters for creating a new session.
NewSessionResponse: Response from creating a new session.
NumberPropertySchemaunstable_elicitation: Schema for number (floating-point) properties in an elicitation form.
PermissionOption: An option presented to the user when requesting permission.
PermissionOptionId: Unique identifier for a permission option.
Plan: An execution plan for accomplishing complex tasks.
PlanCapabilities: UNSTABLE
PlanEntry: A single entry in the execution plan.
PlanFile: UNSTABLE
PlanIdunstable_plan_operations: UNSTABLE
PlanItems: UNSTABLE
PlanMarkdown: UNSTABLE
PlanRemoved: UNSTABLE
PlanUpdate: UNSTABLE
Positionunstable_nes: A zero-based position in a text document.
PromptCapabilities: Prompt capabilities supported by the agent in session/prompt requests.
PromptRequest: Request parameters for sending a user prompt to the agent.
PromptResponse: Response from processing a user prompt.
ProtocolVersion: Protocol version identifier.
ProviderCurrentConfigunstable_llm_providers: UNSTABLE
ProviderInfo: UNSTABLE
ProvidersCapabilities: UNSTABLE
Rangeunstable_nes: A range in a text document, expressed as start and end positions.
RawValue: Reference to a range of bytes encompassing a single valid JSON value in the input data.
ReadTextFileRequest: Request to read content from a text file.
ReadTextFileResponse: Response containing the contents of a text file.
RejectNesNotificationunstable_nes: Notification sent when a suggestion is rejected.
ReleaseTerminalRequest: Request to release a terminal and free its resources.
ReleaseTerminalResponse: Response to terminal/release method
RequestPermissionRequest: Request for user permission to execute a tool call.
RequestPermissionResponse: Response to a permission request.
ResourceLink: A resource that the server is capable of reading, included in a prompt or tool call result.
ResumeSessionRequest: Request parameters for resuming an existing session.
ResumeSessionResponse: Response from resuming an existing session.
SelectedPermissionOutcome: The user selected one of the provided options.
SessionAdditionalDirectoriesCapabilities: Capabilities for additional session directories support.
SessionCapabilities: Session capabilities supported by the agent.
SessionCloseCapabilities: Capabilities for the session/close method.
SessionConfigBooleanunstable_boolean_config: UNSTABLE
SessionConfigGroupId: Unique identifier for a session configuration option value group.
SessionConfigId: Unique identifier for a session configuration option.
SessionConfigOption: A session configuration option selector and its current state.
SessionConfigSelect: A single-value selector (dropdown) session configuration option payload.
SessionConfigSelectGroup: A group of possible values for a session configuration option.
SessionConfigSelectOption: A possible value for a session configuration option.
SessionConfigValueId: Unique identifier for a session configuration option value.
SessionDeleteCapabilities: Capabilities for the session/delete method.
SessionForkCapabilities: UNSTABLE
SessionId: A unique identifier for a conversation session between a client and agent.
SessionInfo: Information about a session returned by session/list
SessionInfoUpdate: Update to session metadata. All fields are optional to support partial updates.
SessionListCapabilities: Capabilities for the session/list method.
SessionMode: A mode the agent can operate in.
SessionModeId: Unique identifier for a Session Mode.
SessionModeState: The set of modes and the one currently active.
SessionNotification: Notification containing a session update from the agent.
SessionResumeCapabilities: Capabilities for the session/resume method.
SetProviderRequest: UNSTABLE
SetProviderResponse: UNSTABLE
SetSessionConfigOptionRequest: Request parameters for setting a session configuration option.
SetSessionConfigOptionResponse: Response to session/set_config_option method.
SetSessionModeRequest: Request parameters for setting a session mode.
SetSessionModeResponse: Response to session/set_mode method.
SkipListenertracing: Inspector passed to every VecSkipError<_, SkipListener> in the protocol types so that malformed list entries dropped during deserialization are surfaced to observability tooling rather than vanishing silently.
StartNesRequestunstable_nes: Request to start an NES session.
StartNesResponseunstable_nes: Response to nes/start.
StringPropertySchemaunstable_elicitation: Schema for string properties in an elicitation form.
SuggestNesRequestunstable_nes: Request for a code suggestion.
SuggestNesResponseunstable_nes: Response to nes/suggest.
Terminal: Embed a terminal created with terminal/create by its id.
TerminalExitStatus: Exit status of a terminal command.
TerminalId
TerminalOutputRequest: Request to get the current output and status of a terminal.
TerminalOutputResponse: Response containing the terminal output and exit status.
TextContent: Text provided to or from an LLM.
TextDocumentContentChangeEventunstable_nes: A content change event for a document.
TextResourceContents: Text-based resource contents.
TitledMultiSelectItemsunstable_elicitation: Items definition for titled multi-select enum properties.
ToolCall: Represents a tool call that the language model has requested.
ToolCallId: Unique identifier for a tool call within a session.
ToolCallLocation: A file location being accessed or modified by a tool.
ToolCallUpdate: An update to an existing tool call.
ToolCallUpdateFields: Optional fields that can be updated in a tool call.
UnstructuredCommandInput: All text that was typed after the command name is provided as input.
UntitledMultiSelectItemsunstable_elicitation: Items definition for untitled multi-select enum properties.
UrlElicitationRequiredDataunstable_elicitation: UNSTABLE
UrlElicitationRequiredItemunstable_elicitation: UNSTABLE
Usage: UNSTABLE
UsageUpdate: Context window and cost update for a session.
WaitForTerminalExitRequest: Request to wait for a terminal command to exit.
WaitForTerminalExitResponse: Response containing the exit status of a terminal command.
WorkspaceFolderunstable_nes: A workspace folder.
WriteTextFileRequest: Request to write content to a text file.
WriteTextFileResponse: Response to fs/write_text_file

Enums§

AgentNotification: All possible notifications that an agent can send to a client.
AgentRequest: All possible requests that an agent can send to a client.
AgentResponse: All possible responses that an agent can send to a client.
AuthMethod: Describes an available authentication method.
AvailableCommandInput: The input specification for a command.
ClientNotification: All possible notifications that a client can send to an agent.
ClientRequest: All possible requests that a client can send to an agent.
ClientResponse: All possible responses that a client can send to an agent.
ContentBlock: Content blocks represent displayable information in the Agent Client Protocol.
ElicitationActionunstable_elicitation: UNSTABLE
ElicitationContentValueunstable_elicitation
ElicitationModeunstable_elicitation: UNSTABLE
ElicitationPropertySchemaunstable_elicitation: Property schema for elicitation form fields.
ElicitationSchemaTypeunstable_elicitation: Type discriminator for elicitation schemas.
ElicitationScopeunstable_elicitation: UNSTABLE
ElicitationStringTypeunstable_elicitation: Items definition for untitled multi-select enum properties.
ElicitationUrlOnlyModeunstable_elicitation: Type discriminator for URL-only elicitation error items.
EmbeddedResourceResource: Resource content that can be embedded in a message.
ErrorCode: Predefined error codes for common JSON-RPC and ACP-specific errors.
LlmProtocolunstable_llm_providers: UNSTABLE
MaybeUndefined: Similar to Option, but it has three states, undefined, null and x.
McpServer: Configuration for connecting to an MCP (Model Context Protocol) server.
MultiSelectItemsunstable_elicitation: Items for a multi-select (array) property schema.
NesDiagnosticSeverityunstable_nes: Severity of a diagnostic.
NesRejectReasonunstable_nes: The reason a suggestion was rejected.
NesSuggestionunstable_nes: A suggestion returned by the agent.
NesTriggerKindunstable_nes: What triggered the suggestion request.
PermissionOptionKind: The type of permission option being presented to the user.
PlanEntryPriority: Priority levels for plan entries.
PlanEntryStatus: Status of a plan entry in the execution flow.
PlanUpdateContentunstable_plan_operations: UNSTABLE
PositionEncodingKindunstable_nes: The encoding used for character offsets in positions.
ProtocolLevelNotificationunstable_cancel_request: General protocol-level notifications that all sides are expected to implement.
RequestPermissionOutcome: The outcome of a permission request.
Role: The sender or recipient of messages and data in a conversation.
SessionConfigKind: Type-specific session configuration option payload.
SessionConfigOptionCategory: Semantic category for a session configuration option.
SessionConfigOptionValueunstable_boolean_config: UNSTABLE
SessionConfigSelectOptions: Possible values for a session configuration option.
SessionUpdate: Different types of updates that can be sent during session processing.
StopReason: Reasons why an agent stops processing a prompt turn.
StringFormatunstable_elicitation: String format types for string properties in elicitation schemas.
TextDocumentSyncKindunstable_nes: How the agent wants document changes delivered.
ToolCallContent: Content produced by a tool call.
ToolCallStatus: Execution status of a tool call.
ToolKind: Categories of tools that can be invoked.

Constants§

AGENT_METHOD_NAMES: Constant containing all agent method names.
CLIENT_METHOD_NAMES: Constant containing all client method names.
PROTOCOL_LEVEL_METHOD_NAMESunstable_cancel_request: Constant containing all agent method names.

Traits§

IntoMaybeUndefined: Utility trait for builder methods for optional values. This allows the caller to either pass in the value itself without wrapping it in Some, or to just pass in an Option if that is what they have, or set it back to undefined.
IntoOption: Utility trait for builder methods for optional values. This allows the caller to either pass in the value itself without wrapping it in Some, or to just pass in an Option if that is what they have.

Type Aliases§

Meta: Value attached to a given ACP type on the _meta field.
Response
Result