There are sour leads, hungry students and even a few charlatans among the roughly 5,000 Ugandan refugees here, ready to talk for a few dollars.

Then there is Peter, difficult to find even with good contacts, but in the end willing to talk for nothing except guaranteed annymity, even from the Keynan police.

"I was among the ones who planned the coup," he begins, and so tumble forth the intricate details of the unsuccessful attempt three months ago on the life of Uganda's Idi Amin.

According to Peter's story:

The coup was not spontaneous but carefully planned over 18 months, involving scores of military men in key units and hundreds of sophisticated Soviet-made weapons.

Contrary to general acceptance analyses among Western diplomats in Nairobi, the plot was to have gone beyond the elimination of Amin. A commission of soldiers and civilians had been formed to organize an interim government until a parliamentary system based on the British model could be formed.

Key Amin aides - about 30 of them - were to be seized and put on trial as soon as the president was dead. A dozen important military units, including the heavily armored Malire Mechanized Division, had been infiltrated and were to respond on word of Amin's death.

Perhaps most surprising, key diplomats in a dozen African countries - and possibly in the United States - had been tipped off in advance that a new government might come to power soon. The committee of 11 Ugandans who plotted the coup had been assured through channels that diplomatic recognition for the new government would come within hours, at least in Africa.

The extent of the coup's reported organization is not surprising, given the wholesale chaos Amin maintains in Uganda. But some of the people reportedly involved are highly influential figures.

Paul Muwanga, former Ugandan ambassador to Greece and France, now living in exile in London, is believed to have been at least a consultant to the coup-planners, and Peter said Muwanga had met with some of them in Nairobi in the months before the assassination attempt.

The apparent level of planning and co-ordination among military units, according to Peter's account, would have been impressive indeed.

But all hinged on Amin's death.

"Amin was to die, not to be captured, and nothing was to be done until he was dead," explained Peter.

Tragically for the plotters, everything seem to go wrong at the last minute. According to Peter's account:

Two months of following Amin's every move around Kampala and Entebbe by bugging his personal radio operator came to nothing when the mercurial dictator twice changed plans at the last minute.

On June 16, he inexplicably moved a budget meeting from the Parliament building in Kampala to another site, foiling a well-prepared assault.

The next day, a Moslem holy day, he failed to appear for mid-day prayers at a mosque where he was expected.

The all-or-nothing attack scheduled for June 18 feel apart, too, with just seven hours to go. One of the original leaders, after a year and a half of involvement in the plot, left it and spilled everything to an Amin aide.

The attack was to have been at Amin's poolside Cabinet meeting in Entebbe that noon, but it wasn't until 11:30 a.m. that the coup leaders learned they had been betrayed.

Peter contends that Amin was wounded when his bodyguards, trying to whisk him away to safety in Kampala, drove into a hall of gun fire in Bayitabiri, a village where a squad of rebel sympathizers was awaiting word of his death to seize an ammunition dump.

Ironically, Peter said, had the Bayitabiri squad held its fire, Amin would have run into a better-armed group of 30 men 15 minutes down the road. This group was on its way to find him in Entebbe.

Today Amin is unquestionably in full power in Uganda.

There remain, however, some unanswered questions about the coup.

Where, for instance, could the leaders have acquired 800 of the latest Soviet weapons, apparently far superior to the hand-me-down gear the Russians give Amin? Peter rules out Moscow, but will not explain.

What were the political leanings of the coup leaders? Peter will say only that there would eventually have been a parliamentary form of elected representatives.

What happened to the rest of the arms and the coup sympathizers? Amin claims to have found fewer than 100 weapons, ostensibly leaving 700 others hidden somewhere in Uganda, and according to news accounts and official records here, Peter arrived in Kenya at the head of a 17-man, well-armed group the day after the coup.