It was well-received by parents and students who have been agitating for the district to raise expectations for and performance of lower-achieving students.
If enacted by the school board in May, Skelly's proposal would be phased in, taking full effect with the graduating class of 2018 today's sixth-graders.
It would not affect the vast majority of students. About 80 percent of Palo Alto's high school graduates already meet or exceed the entrance criteria for California State University (CSU) and the University of California (UC), the so-called "A-G requirements."
Rather, the proposal is aimed at increasing academic achievement among the roughly 20 percent each year who graduate without fulfilling the CSU/UC entrance requirements, a group that is disproportionately low-income, African-American or Hispanic.
Specifically, the proposal would add two years of foreign language, which Skelly said could be fulfilled in various ways, including by taking a test.
For the classes of 2016 and 2017 (today's seventh- and eighth-graders), three years of math, including geometry, would be required compared with today's two years.
The following year, Algebra 2 would be explicitly specified in the three-year math requirement.
The current two-year science requirement also would specify a laboratory science, as is required by CSU/UC.
This week was the second time Skelly has proposed "A-G alignment" the first was last May. At that time, he suggested a form of "waiver" for students unable or unwilling to complete the four-year college-prep curriculum, leading to protest from special-education parents and others that a waiver would amount to a black mark on high school diplomas.
But Tuesday's proposal offering "alternative graduation requirements" rather than "waivers" appeared to be better-received by special-education advocates.
The customized alternative-graduation requirements would be available to students who have "explicit post-secondary plans" that differ significantly from the four-year college path.
The proposal also was praised by parent and student backers of "A-G for all," who packed the board room in support.
"We wholeheartedly support the superintendent's recommendation, even though we'd like to see it happen sooner rather than later," said parent Ken Dauber, founder of the anti-stress group We Can Do Better Palo Alto, who less than a year ago charged that the Palo Alto school district "needs new leadership."
Parent Sara Woodham said the plan is "moving in the right direction.
"Alignment is a blunt instrument, a forcing function," she said. "But it's a forcing function to get better at educating our kids. In the process we have to tackle the business of expectations the district has for our kids and the learning environment that we set."
Seven Palo Alto High School students all members of the Student Equity Action Network turned out to advocate "A-G for all."
"I can't wait to see the positive effects of Dr. Skelly's proposal," said Paly senior Lucas Brooks, to applause from the audience.
Skelly said he will fill out details of the plan and bring it back to the board in May for discussion on May 8 and a vote May 22.
School board members generally praised the plan, calling it a "blunt instrument" but perhaps necessary to make headway against a socio-economic and racial achievement gap that long has plagued the schools here and elsewhere.
"It's a blunt instrument but, Dr. Skelly, you've sharpened it," board vice-president Dana Tom said. "Of those students this will affect, hopefully there will be a good portion who will be capable of meeting A-G. For students who aren't, you've found a way to accommodate alternative pathways."
But board member Barb Mitchell cautioned that while the plan goes in the right direction, "I'm less optimistic that this is the right tool to get there."
She worried that the district lacks the structure to provide timely "second instruction" to the consistent number of students who fall behind on the A-G path. If a failing student drops a class in November, for example, the next chance to make it up in some cases isn't until the following school year, placing the student far behind.
"My bias is to debug our plan before we launch, to build the runway first," Mitchell said.
Board member Melissa Baten Caswell said the new plan should be considered "an opportunity for us to think about 'first instruction.'
"I'd like us to keep from thinking of it as 'second instruction,'" she said.
Skelly said the new graduation requirements would force positive change.
"My bias is, if we were to adopt these and do nothing else, it would force conversations around students where they are introspective about what they're doing, and the consequences of what they're doing, and we'd be better off than we are right now," he said.
"The principals are very fired up about this and believe it's the right work," he said, adding that teachers "have lots of different views" and are split on the issue.