Add agent library

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

pkg/agent/guardrail.go

@@ -0,0 +1,38 @@
+// 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"
+
+	"go.probo.inc/probo/pkg/llm"
+)
+
+type (
+	GuardrailResult struct {
+		Tripwire bool
+		Message  string
+	}
+
+	InputGuardrail interface {
+		Name() string
+		Check(ctx context.Context, messages []llm.Message) (*GuardrailResult, error)
+	}
+
+	OutputGuardrail interface {
+		Name() string
+		Check(ctx context.Context, message llm.Message) (*GuardrailResult, error)
+	}
+)