codespace/internal/acp/messages.go

package acp

import "encoding/json"

// jsonRPCMessage is the raw JSON-RPC 2.0 envelope used over NDJSON.
type jsonRPCMessage struct {
	JSONRPC string          `json:"jsonrpc"`
	ID      *int            `json:"id,omitempty"`
	Method  string          `json:"method,omitempty"`
	Params  json.RawMessage `json:"params,omitempty"`
	Result  json.RawMessage `json:"result,omitempty"`
	Error   *rpcError       `json:"error,omitempty"`
}

// rpcError is a JSON-RPC 2.0 error object.
type rpcError struct {
	Code    int    `json:"code"`
	Message string `json:"message"`
	Data    any    `json:"data,omitempty"`
}

// InitializeParams is sent once to negotiate the ACP session.
type InitializeParams struct {
	ProtocolVersion    int                `json:"protocolVersion"`
	ClientCapabilities ClientCapabilities `json:"clientCapabilities"`
	ClientInfo         ClientInfo         `json:"clientInfo"`
}

// ClientCapabilities describes tools the client exposes to the agent.
type ClientCapabilities struct {
	FS ClientFSCapabilities `json:"fs"`
}

// ClientFSCapabilities declares filesystem support.
type ClientFSCapabilities struct {
	ReadTextFile  bool `json:"readTextFile"`
	WriteTextFile bool `json:"writeTextFile"`
}

// ClientInfo identifies this client to the agent.
type ClientInfo struct {
	Name    string `json:"name"`
	Version string `json:"version"`
}

// InitializeResult is returned by the agent for initialize.
type InitializeResult struct {
	ProtocolVersion   int `json:"protocolVersion"`
	AgentCapabilities any `json:"agentCapabilities"`
	AgentInfo         any `json:"agentInfo"`
}

// SessionNewParams starts a new agent session for a workspace.
type SessionNewParams struct {
	Cwd        string `json:"cwd"`
	MCPServers []any  `json:"mcpServers"`
}

// SessionNewResult returns the session identifier.
type SessionNewResult struct {
	SessionID string `json:"sessionId"`
}

// PromptMessage is a single user message part.
type PromptMessage struct {
	Type string `json:"type"`
	Text string `json:"text"`
}

// SessionPromptParams sends user input to the agent.
type SessionPromptParams struct {
	SessionID string          `json:"sessionId"`
	Prompt    []PromptMessage `json:"prompt"`
}

// SessionPromptResult is the final response for a prompt turn.
type SessionPromptResult struct {
	StopReason string `json:"stopReason"`
}

// SessionCancelParams interrupts an in-flight turn.
type SessionCancelParams struct {
	SessionID string `json:"sessionId"`
}

// SessionUpdateParams is the payload of a session/update notification.
type SessionUpdateParams struct {
	SessionID string `json:"sessionId"`
	Update    Update `json:"update"`
}

// Update carries a single streamed update from the agent.
type Update struct {
	SessionUpdate string `json:"sessionUpdate"`
	MessageID     string `json:"messageId,omitempty"`
	Content       ContentBlock `json:"content,omitempty"`
	ToolCallID    string `json:"toolCallId,omitempty"`
}

// ContentBlock is a content payload in session/update notifications.
type ContentBlock struct {
	Type string `json:"type"`
	Text string `json:"text,omitempty"`
}

// FSReadParams is sent by the agent to read a workspace file.
type FSReadParams struct {
	Path      string `json:"path"`
	SessionID string `json:"sessionId"`
	Line      *int   `json:"line,omitempty"`
	Limit     *int   `json:"limit,omitempty"`
}

// FSReadResult returns file contents to the agent.
type FSReadResult struct {
	Content string `json:"content"`
}

// FSWriteParams is sent by the agent to write a workspace file.
type FSWriteParams struct {
	Path      string `json:"path"`
	SessionID string `json:"sessionId"`
	Content   string `json:"content"`
}

// FSWriteResult is the empty success response for fs/write_text_file.
type FSWriteResult struct{}