feat(agentsessions): import other coding agents' local sessions and continue them in Zero

internal/acp/agent.go

@@ -87,6 +87,8 @@ type Agent struct {
 type turnRecord struct {
 	user      string
 	assistant string
+	imported  bool
+	boundary  bool
 }
 
 type acpSession struct {
@@ -257,18 +259,19 @@ func (a *Agent) activatePersistedSession(ctx context.Context, p LoadSessionParam
 	if operation == persistedSessionResume && !sessions.IsResumableKind(meta.SessionKind) {
 		return nil, RPCError(codeInvalidParams, "session is not resumable: "+p.SessionID)
 	}
-	if strings.TrimSpace(meta.Cwd) == "" {
+	persistedCwd := sessions.OperationalCwd(*meta)
+	if strings.TrimSpace(persistedCwd) == "" {
 		return nil, RPCError(codeInvalidParams, "session has no persisted workspace: "+p.SessionID)
 	}
 	// SAME RULE ON THE WAY IN. Omitting a relative entry from the listing is not
 	// enough: a stored "." still resolves against this process's directory, so a
 	// client that hands back that same directory as its cwd would be sold the
 	// invented root as a match. A workspace that cannot be identified is not one
 	// this session can be restored into.
-	if !filepath.IsAbs(meta.Cwd) {
+	if !filepath.IsAbs(persistedCwd) {
 		return nil, RPCError(codeInvalidParams, "session workspace is not an absolute path, so it cannot be identified: "+p.SessionID)
 	}
-	persistedRoot, err := a.deps.ResolveWorkspaceRoot(meta.Cwd)
+	persistedRoot, err := a.deps.ResolveWorkspaceRoot(persistedCwd)
 	if err != nil {
 		return nil, RPCError(codeInvalidParams, "persisted session workspace is unavailable: "+err.Error())
 	}
@@ -305,7 +308,10 @@ func (a *Agent) activatePersistedSession(ctx context.Context, p LoadSessionParam
 	if err != nil {
 		return nil, RPCError(codeInternalError, "config: "+err.Error())
 	}
-	if persistedModel := strings.TrimSpace(meta.ModelID); persistedModel != "" && (!restrictModels || modelChoiceExists(models, persistedModel)) {
+	persistedModel := strings.TrimSpace(meta.ModelID)
+	imported := sessions.IsImportedSession(*meta)
+	locallySelected := !imported || meta.ModelSelectedLocally
+	if persistedModel != "" && locallySelected && (!restrictModels || modelChoiceExists(models, persistedModel)) {
 		model = persistedModel
 		if !modelChoiceExists(models, persistedModel) {
 			models = append(models, SessionConfigOptionValue{Value: persistedModel, Name: persistedModel})
@@ -389,7 +395,8 @@ func (a *Agent) handleSessionList(_ context.Context, params json.RawMessage) (an
 		// a session whose workspace has since been deleted, and a legacy entry
 		// holding a relative path, which was then reported as cwd "." even though
 		// ACP requires SessionInfo.cwd to be absolute.
-		if strings.TrimSpace(item.Cwd) == "" {
+		operationalCwd := sessions.OperationalCwd(item)
+		if strings.TrimSpace(operationalCwd) == "" {
 			continue
 		}
 		// A RELATIVE PERSISTED CWD HAS NO RECOVERABLE IDENTITY. Resolving one
@@ -399,10 +406,10 @@ func (a *Agent) handleSessionList(_ context.Context, params json.RawMessage) (an
 		// project's configuration, files and tools. The original base is not
 		// knowable from the metadata, so the honest answer is to omit the entry
 		// rather than to guess at it.
-		if !filepath.IsAbs(item.Cwd) {
+		if !filepath.IsAbs(operationalCwd) {
 			continue
 		}
-		itemRoot, err := a.deps.ResolveWorkspaceRoot(item.Cwd)
+		itemRoot, err := a.deps.ResolveWorkspaceRoot(operationalCwd)
 		if err != nil {
 			continue
 		}
@@ -924,6 +931,7 @@ func (a *Agent) loadHistory(sessionID string, requireHistoryLog bool) ([]turnRec
 	var messages []persistedMessage
 	activeToolCalls := make(map[string]string)
 	var pendingUser string
+	var pendingImported, pendingBoundary bool
 	havePending := false
 	for _, e := range events {
 		if e.Type == sessions.EventCompaction {
@@ -935,7 +943,8 @@ func (a *Agent) loadHistory(sessionID string, requireHistoryLog bool) ([]turnRec
 				continue
 			}
 			var payload struct {
-				Summary string `json:"summary"`
+				Summary         string `json:"summary"`
+				ImportedContext bool   `json:"importedEvent"`
 			}
 			if json.Unmarshal(raw, &payload) != nil || strings.TrimSpace(payload.Summary) == "" {
 				continue
@@ -945,8 +954,10 @@ func (a *Agent) loadHistory(sessionID string, requireHistoryLog bool) ([]turnRec
 				role:    "assistant",
 				content: payload.Summary,
 			})
-			records = append(records, turnRecord{user: pendingUser, assistant: payload.Summary})
+			records = append(records, turnRecord{user: pendingUser, assistant: payload.Summary, imported: payload.ImportedContext})
 			pendingUser = ""
+			pendingImported = false
+			pendingBoundary = false
 			havePending = false
 			continue
 		}
@@ -988,8 +999,10 @@ func (a *Agent) loadHistory(sessionID string, requireHistoryLog bool) ([]turnRec
 			continue
 		}
 		var msg struct {
-			Role    string `json:"role"`
-			Content string `json:"content"`
+			Role     string `json:"role"`
+			Content  string `json:"content"`
+			Imported bool   `json:"importedEvent"`
+			Boundary bool   `json:"importedReferenceBoundary"`
 		}
 		if json.Unmarshal(raw, &msg) != nil {
 			continue
@@ -998,19 +1011,27 @@ func (a *Agent) loadHistory(sessionID string, requireHistoryLog bool) ([]turnRec
 		case "user":
 			messages = append(messages, persistedMessage{eventID: persistedMessageIdentity(sessionID, e), role: msg.Role, content: msg.Content})
 			if havePending {
-				records = append(records, turnRecord{user: pendingUser})
+				records = append(records, turnRecord{user: pendingUser, imported: pendingImported, boundary: pendingBoundary})
 			}
 			pendingUser = msg.Content
+			pendingImported = msg.Imported
+			pendingBoundary = msg.Boundary
 			havePending = true
 		case "assistant":
 			messages = append(messages, persistedMessage{eventID: persistedMessageIdentity(sessionID, e), role: msg.Role, content: msg.Content})
-			records = append(records, turnRecord{user: pendingUser, assistant: msg.Content})
+			records = append(records, turnRecord{
+				user: pendingUser, assistant: msg.Content,
+				imported: pendingImported || msg.Imported,
+				boundary: pendingBoundary || msg.Boundary,
+			})
 			pendingUser = ""
+			pendingImported = false
+			pendingBoundary = false
 			havePending = false
 		}
 	}
 	if havePending {
-		records = append(records, turnRecord{user: pendingUser})
+		records = append(records, turnRecord{user: pendingUser, imported: pendingImported, boundary: pendingBoundary})
 	}
 	return records, messages, rehydrateWarning, nil
 }
@@ -1064,6 +1085,11 @@ func replayToolUpdate(event sessions.Event) *ToolCallUpdate {
 		Output:       payload.Output,
 		ChangedFiles: append([]string(nil), payload.ChangedFiles...),
 	})
+	if status == tools.StatusUnknown {
+		// ACP has no unknown result status. Omitting the optional status keeps
+		// this replay neutral instead of inventing successful completion.
+		upd.Status = ""
+	}
 	return &upd
 }
 
@@ -1116,7 +1142,14 @@ func buildPrompt(history []turnRecord, userText string) string {
 	}
 	var b strings.Builder
 	b.WriteString("Conversation so far:\n")
+	importedLabeled := false
 	for _, t := range history {
+		if t.imported && !importedLabeled {
+			b.WriteString("Context boundary: ")
+			b.WriteString(sessions.ImportedBoundaryText("another agent's"))
+			b.WriteString("\n")
+			importedLabeled = true
+		}
 		b.WriteString("User: ")
 		b.WriteString(t.user)
 		b.WriteString("\n")
@@ -1125,6 +1158,11 @@ func buildPrompt(history []turnRecord, userText string) string {
 			b.WriteString(t.assistant)
 			b.WriteString("\n")
 		}
+		if t.boundary {
+			importedLabeled = true
+		} else if !t.imported {
+			importedLabeled = false
+		}
 	}
 	b.WriteString("\n---\nContinue with this request:\n")
 	b.WriteString(userText)