However, insiders say Gandhi remains instinctively wary of economic liberalisation and trimming the budget deficit.
For months, she had held out against cutting fuel subsidies that are aimed at the poor and the country's rural majority, fearing the impact on the Congress party's fortunes.
She only agreed when Singh and Chidambaram spelled out that new growth generated by reforms and improved investor sentiment would have a trickle-down effect and provide funds for welfare spending in time for elections due by mid-2014.
"They explained to Mrs Gandhi that social benefits for the poor will need deep pockets," said a Congress party source who declined to be named because the discussions were confidential.
Reuters reviewed more than 30 letters written by Gandhi to the prime minister and US diplomatic cables released by WikiLeaks that portray her as passionate about social issues, and attached to protecting the poor.
That means the sudden burst of reforms could be cut short if Gandhi - who Forbes magazine ranks as the world's sixth most powerful woman - sees no benefits for the rural poor on whom her party relies for votes.
Indeed, party sources said she will now focus on passing a bill on universal food security in December, a populist plan that would cost billions of dollars at a time when her government is under intense pressure to rein in spending.
"She just wants enough budgetary resources available to finance her welfare schemes," said Swapan Dasgupta, a prominent journalist and commentator who leans towards the opposition.
"She has never spoken about reforms. What she has done is make Congress think of reforms as a low priority and a political liability - she has ingrained that mindset in the party."
A request to interview Gandhi was declined.