Add agent library

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

pkg/agent/agent_tool.go

@@ -0,0 +1,87 @@
+// 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"
+	"encoding/json"
+	"fmt"
+
+	"go.probo.inc/probo/pkg/llm"
+)
+
+type (
+	agentTool struct {
+		agent       *Agent
+		toolName    string
+		description string
+		schema      json.RawMessage
+	}
+
+	agentToolParams struct {
+		Input string `json:"input" jsonschema:"The input to send to the agent"`
+	}
+)
+
+var (
+	agentToolParamsSchema = jsonSchemaFor[agentToolParams]()
+)
+
+func newAgentTool(agent *Agent, name, description string) *agentTool {
+	return &agentTool{
+		agent:       agent,
+		toolName:    name,
+		description: description,
+		schema:      agentToolParamsSchema,
+	}
+}
+
+func (t *agentTool) Name() string { return t.toolName }
+
+func (t *agentTool) Definition() llm.Tool {
+	return llm.Tool{
+		Name:        t.toolName,
+		Description: t.description,
+		Parameters:  t.schema,
+	}
+}
+
+func (t *agentTool) Execute(ctx context.Context, arguments string) (ToolResult, error) {
+	var params agentToolParams
+
+	if err := json.Unmarshal([]byte(arguments), &params); err != nil {
+		return ToolResult{
+			Content: fmt.Sprintf("Invalid parameters: %s", err.Error()),
+			IsError: true,
+		}, nil
+	}
+
+	result, err := t.agent.Run(
+		ctx,
+		[]llm.Message{
+			{
+				Role: llm.RoleUser,
+				Parts: []llm.Part{
+					llm.TextPart{Text: params.Input},
+				},
+			},
+		},
+	)
+	if err != nil {
+		return ToolResult{}, err
+	}
+
+	return ToolResult{Content: result.FinalMessage().Text()}, nil
+}