When he leaves the Afghan battlefield for the CIA's headquarters in Langley, Va., Gen. David Petraeus will have an opportunity to put his imprint on the spy agency, possibly shaking up the way it does business.

Petraeus already has a deep understanding of what he perceives to be the agency's weaknesses and strengths, as a commander who has drawn on CIA information to fight the wars in Iraq and Afghanistan. As a military man who values discipline and honesty, he has a reputation of holding people accountable who serve under his command.

"He doesn't suffer fools," said Peter Mansoor, former executive officer to Petraeus in Iraq.

Intelligence experts are watching closely to see how Petraeus will tackle his new job at the CIA, an organization that has not welcomed outsiders who think they know best.

Petraeus will need every ounce of his considerable political talent to bring about change without causing an agency revolt, like the one against former CIA Director Porter Goss. When Goss tried to make significant but controversial changes, his staff quietly ignored or slow-walked his orders. If Petraeus tries to change too much too fast, longtime CIA employees may wait him out.

But Petraeus, the most famous general of his generation, might just have the clout to improve the CIA, making it a more effective and efficient spy agency and one where accountability doesn't roll downhill.

The four-star general with two wars under his belt has ended the careers of senior commanders for civilian casualties he believes could have been avoided, or simply dismissed those on his staff who weren't pulling their weight.

The current CIA director, Leon Panetta, is generally credited with improving morale inside the agency. But Panetta also was heavily criticized for not disciplining CIA officers after a suicide bombing in Afghanistan that killed seven agency employees and wounded six.

Petraeus can also be forgiving. He came up with unique punishments for troops who didn't measure up, recalls Paula Broadwell, an author and West Point graduate who has spent time with the general since 2008, working on his biography.

She recalled a fellow cadet who was kicked out of West Point and demoted to enlisted ranks for an honor violation. His then-commander, Petraeus, sent him to U.S. Army Ranger school, a physically demanding six-month test of body and will. When the soldier passed the course, Petraeus wrote a letter of support to return him to West Point, to set an example that redemption is possible, Broadwell said.

Beyond demanding more accountability, Petraeus is expected to push the highly secretive and turf-conscious CIA to mount more operations and better share information with other parts of the intelligence community.

Military intelligence officials who have worked in Afghanistan have complained that the CIA keeps to itself information gleaned from its sources, forcing the military to create duplicate human intelligence networks both to track militants and protect its own bases. Petraeus will look to fix this problem and beef up the CIA's human intelligence operations, pushing officers to look beyond al-Qaida, intelligence experts said.

Former CIA officer Bruce Riedel said Petraeus was upset to find the CIA had failed to focus on the Afghan Taliban when he arrived to take over the campaign from now-retired Gen. Stanley McChrystal.

In its hunt for Osama bin Laden and deputy Ayman al-Zawahiri, Riedel said Petraeus has noted that the CIA didn't put enough work into understanding the Taliban or tribal networks that he said he needed to fight a counterinsurgency campaign.

Petraeus is also known for pushing his troops for concrete measures of success, like the numbers of kills and captures in Afghanistan made possible by a quadrupling of special operations forces there. Petraeus then pushed to declassify those figures and share them publicly, touting them as proof of coalition success after the surge of some 30,000 forces under his command.

Petraeus also might bring something to the agency that could really rattle those used to working in anonymity: less secrecy.

When Petraeus took over in Afghanistan, he opened the coalition's roughly 20 detention centers to International Red Cross inspection, including the top-secret facility at Bagram Air Base, run by the Joint Special Operations Command, and staffed by CIA interrogators and analysts.

When former detainees who said they were held at the secret facility complained to human rights groups of forced nudity, the special operations staff stopped the practice at Petraeus' direction.

And it's clear he won't tolerate the CIA getting too dirty. He pressed allies in Iraq and Afghanistan to fire officers he found were committing atrocities.

Mansoor, now a professor of military history at Ohio State University, said that in 2007, Petraeus pressured the Iraqi government to fire every police brigade commander and two-thirds of the battalion commanders, despite the political friction that produced.

He similarly pressured Afghan officials to fire dozens of police chiefs.