Add agent library

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

pkg/agent/context.go

@@ -0,0 +1,53 @@
+// 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"
+	"fmt"
+)
+
+type runContextKey struct{}
+
+func WithRunContext(ctx context.Context, val any) context.Context {
+	return context.WithValue(ctx, runContextKey{}, val)
+}
+
+func RunContextFrom[C any](ctx context.Context) C {
+	val := ctx.Value(runContextKey{})
+	if val == nil {
+		var zero C
+		panic(fmt.Sprintf("agent: no run context found (expected %T)", zero))
+	}
+
+	typed, ok := val.(C)
+	if !ok {
+		var zero C
+		panic(fmt.Sprintf("agent: run context type mismatch: stored %T, requested %T", val, zero))
+	}
+
+	return typed
+}
+
+func TryRunContextFrom[C any](ctx context.Context) (C, bool) {
+	val := ctx.Value(runContextKey{})
+	if val == nil {
+		var zero C
+		return zero, false
+	}
+
+	typed, ok := val.(C)
+	return typed, ok
+}