An example with a verb, as well as a noun?

Question

I was directed to this (very useful !) lesson - i.e., https://spanish.kwiziq.com/my-languages/spanish/view/7122 - from a C1 writing exercise ["Charity Kings' Parade] - to explain the structure of this sentence: "Tengo pensado llevar un paraguas". < This is actually a bit different from the examples given in the lesson, because it is not a noun which we "tenemos pensado"; instead it is the verb "llevar" … [so no noun-agreement is required? - i.e. would we still keep the participle "pensado" unchanged if we said "Tengo pensado llevar mis botas de goma"?] … Thus, it might be useful to add, to the lesson, an example along these lines, i.e., where "Tengo pensado" is followed immediately by a verb.

Inma Sánchez · Accepted Answer

Hola David,
yes. it is indeed a bit different to what the lesson shows as none of the examples given had an infinitive after the participle.
In these sentences: "Tengo pensado llevar un paraguas" and "Tengo pensado llevar mis botas de agua" the participle "pensado" doesn't change from singular to plural. You can think of this this way:
"Tengo pensado llevar un paraguas" = "Tengo pensado algo".
The direct object of "tener pensado" is "algo"; this algo in this case is an action expressed with an infinitive "llevar un paraguas/llevar mis botas de agua".
This infinitive is considered a singular thing, therefore it is going to agree with "pensado". 
We will add a note to the lesson making students aware of this case. Note that this only happens with the participle "pensado" or any other synonym, e.g. "maquinado" (maquinar = to plan/to think through/to plot):

El ladron tenía pensado/maquinado algo. 
El ladrón tenía pensado/maquinado robar dos joyerías ese día.

I hope this clarified it.
Saludos
Inma