Add agent library

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

pkg/agent/session_memory.go

@@ -0,0 +1,84 @@
+// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package agent
+
+import (
+	"context"
+	"sync"
+
+	"go.probo.inc/probo/pkg/llm"
+)
+
+var _ Session = (*memorySession)(nil)
+
+type memorySession struct {
+	mu       sync.RWMutex
+	sessions map[string][]llm.Message
+}
+
+func NewMemorySession() *memorySession {
+	return &memorySession{
+		sessions: make(map[string][]llm.Message),
+	}
+}
+
+func (s *memorySession) Load(_ context.Context, sessionID string) ([]llm.Message, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	msgs, ok := s.sessions[sessionID]
+	if !ok {
+		return nil, nil
+	}
+
+	cp := make([]llm.Message, len(msgs))
+	for i, m := range msgs {
+		cp[i] = copyMessage(m)
+	}
+
+	return cp, nil
+}
+
+func (s *memorySession) Save(_ context.Context, sessionID string, messages []llm.Message) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	cp := make([]llm.Message, len(messages))
+	for i, m := range messages {
+		cp[i] = copyMessage(m)
+	}
+
+	s.sessions[sessionID] = cp
+	return nil
+}
+
+func copyMessage(m llm.Message) llm.Message {
+	cp := llm.Message{
+		Role:       m.Role,
+		ToolCallID: m.ToolCallID,
+	}
+
+	if len(m.Parts) > 0 {
+		cp.Parts = make([]llm.Part, len(m.Parts))
+		copy(cp.Parts, m.Parts)
+	}
+
+	if len(m.ToolCalls) > 0 {
+		cp.ToolCalls = make([]llm.ToolCall, len(m.ToolCalls))
+		copy(cp.ToolCalls, m.ToolCalls)
+	}
+
+	return cp
+}