Python json normalization - nested structure

Using recordpath=['reports'] does roughly what you want. The only exception is that it doesn't capture the reportid column. You can add a line to provide that column.

import pandas as pd
import json
This is a file containing the JSON from the question.
If you already have the JSON loaded into the variable 'data'
you don't need this step
with open('test1165.json', 'rb') as f:
    data = json.load(f)
reportdf = pd.jsonnormalize(data, recordpath=['reports'])
reportdf.insert(0, 'reportid', data['id'])
print(reportdf.tostring())

Printing reportdf gives the following:

   reportid                         body     type outcome.comments outcome.id  outcome.status.failed.both  outcome.status.failed.human  outcome.status.failed.auto  outcome.status.failed.total  outcome.status.open.both  outcome.status.open.human  outcome.status.open.auto  outcome.status.open.total  outcome.status.passed.both  outcome.status.passed.human  outcome.status.passed.auto  outcome.status.passed.total  outcome.status.code.input  outcome.status.code.output  outcome.status.code.canceled  outcome.status.total
0      12345  \n\nGeneral report text.  outcome               []          1                           0                            0                           0                            0                         0                          0                         0                          0                           0                            0                           1                            1                           0                            0                             0                     1
1      12345  \n\nGeneral report text.  outcome               []          2                           0                            0                           0                            0                         0                          0                         0                          0                           0                            0                           1                            1                           0                            0                             0                     1

import json
import pandas as pd
with open("data.json") as f:
    data = json.load(f)
df = pd.jsonnormalize(data, recordpath='reports', meta=['id'])
#rearrange and rename columns
df.insert(0, 'reportid', df.pop('id'))
df.insert(1, 'outcome.id', df.pop('outcome.id'))
print(df.tostring())