Merthyr Tydfil council's leader and acting chief executive are to be given coaching as part of efforts to turn the troubled authority around.
The Welsh Government has announced further help for the council, which has suffered a break-down in relations at the top while facing a £8m shortfall.
A review found that too many in the council did not understand how much the authority needed to change.
Leader Kevin O'Neill said the council has "robust plans in place".
The Welsh Government sent in former Swindon council chief executive John Gilbert to advise the authority after Mr O'Neill asked for help earlier this year.
He has now completed a review, which found Mr O'Neill's own manifesto was not costed or well understood by officers.
Local government minister Julie James has announced a package of support, including a new improvement board chaired by ex-Welsh Local Government Association chief executive Steve Thomas.
Merthyr Tydfil is facing a budget gap of £8.2m next year - the independent-run administration needs help from opposition councillors to govern..
Labour is the largest opposition group.
Mr Gilbert's report said there is little evidence of "collaborative working" operating between the authority's different political groups - although there was a "growing recognition" among political leaders in Merthyr council that they needed to work together.
Neither was there much evidence that councillors and officers at leadership level were working together "in a planned way".
Some officers felt the boundaries of responsibilities have been blurred between themselves and some council members. A number of the councillors were new to the job.
The leader was "seemingly very popular" in the county borough, the advisor said, but was trying to respond to all communication he receives directly, "with none of this being screened".
The former Swindon chief executive said the leader needed more support for the authority to make decisions in his absence, "rather than allowing him to be involved in too many operational requests and enquiries".
Mr Gilbert called for the council to set out a shared, and understood, vision for the future.
"Too many" people in the organisation did not understand the scale of change needed at the authority, he said, expressing concern at a belief in the authority that children's social services was the only service that needed to change.
There was a lack of urgency, Mr Gilbert said, and while officers had developed budget proposals, these were around reductions rather than doing things differently.
Morale at the council had also been "damaged" following the departure of the former chief executive Gareth Chapman, the review found.
Steve Thomas will chair an independent "improvement and assurance board" which will include leading councillors and former senior officials from other local authorities.
He told BBC Wales that the council has questions over its budget "which are not dissimilar to many other authorities around Wales", having not seen its resources increase over the last eight-nine years.
"There are some challenges to the authority that really threaten the services over the next period," he said.
"I'm confident the council will balance its budget. Its got to balance its budget. But at the same time to do that its got to ask itself some really deep questions and its got to change the way it does business."
In a statement Ms James said mentoring and coaching will be provided to Mr O'Neill and acting chief executive Ellis Cooper, and detailed "bespoke" training will be offered to councillors.
The process itself was hit by controversy after one of the advisers that the Welsh Government appointed, former Mansfield mayor Kate Allsop, was named as a Brexit Party parliamentary candidate.
Ms Allsop was subsequently sacked. Mr Gibson wrote that his work had been limited by her departure.
In a statement Mr O'Neill said: "To put the organisation in a strong position for the future, we will need to go through a transformation. I have no doubt whatsoever, with this support from Welsh Government, Merthyr Tydfil will thrive!
"We have already started this journey and have robust plans in place to deliver this transformation."
Dawn Bowden said the report "makes for sobering reading" and added: "As I have stated previously my overriding interest is the quality of services delivered to the citizens in this part of our constituency. This report makes clear that the current situation is unacceptable.
She added that "the focus of the improvement work now required rests with the local authority itself."