Failed to install keybase command line tool

0 info it worked if it ends with ok
1 verbose cli [ 'node',
1 verbose cli '/usr/local/bin/npm',
1 verbose cli 'install',
1 verbose cli '-g',
1 verbose cli 'keybase-installer' ]
2 info using npm@2.7.4
3 info using node@v0.12.2
4 silly cache add args [ 'keybase-installer', null ]
5 verbose cache add spec keybase-installer
6 silly cache add parsed spec { raw: 'keybase-installer',
6 silly cache add scope: null,
6 silly cache add name: 'keybase-installer',
6 silly cache add rawSpec: '',
6 silly cache add spec: '',
6 silly cache add type: 'range' }
7 verbose addNamed keybase-installer@
8 silly addNamed semver.valid null
9 silly addNamed semver.validRange *
10 silly addNameRange { name: 'keybase-installer', range: '*', hasData: false }
11 silly mapToRegistry name keybase-installer
12 silly mapToRegistry using default registry
13 silly mapToRegistry registry https://registry.npmjs.org/
14 silly mapToRegistry uri https://registry.npmjs.org/keybase-installer
15 verbose addNameRange registry:https://registry.npmjs.org/keybase-installer not in flight; fetching
16 verbose request uri https://registry.npmjs.org/keybase-installer
17 verbose request no auth needed
18 info attempt registry request try #1 at 9:23:48 AM
19 verbose request id db18a97123642f7d
20 http request GET https://registry.npmjs.org/keybase-installer
21 info retry will retry, error on last attempt: Error: tunneling socket could not be established, cause=connect ECONNREFUSED
22 info attempt registry request try #2 at 9:23:58 AM
23 http request GET https://registry.npmjs.org/keybase-installer
24 info retry will retry, error on last attempt: Error: tunneling socket could not be established, cause=connect ECONNREFUSED
25 info attempt registry request try #3 at 9:24:58 AM
26 http request GET https://registry.npmjs.org/keybase-installer
27 verbose stack Error: tunneling socket could not be established, cause=connect ECONNREFUSED
27 verbose stack at ClientRequest.onError (/usr/local/lib/node_modules/npm/node_modules/request/node_modules/tunnel-agent/index.js:168:17)
27 verbose stack at ClientRequest.g (events.js:199:16)
27 verbose stack at ClientRequest.emit (events.js:107:17)
27 verbose stack at Socket.socketErrorListener (_http_client.js:271:9)
27 verbose stack at Socket.emit (events.js:107:17)
27 verbose stack at net.js:459:14
27 verbose stack at process._tickCallback (node.js:355:11)
28 verbose cwd /Users/robertnash
29 error Darwin 14.3.0
30 error argv "node" "/usr/local/bin/npm" "install" "-g" "keybase-installer"
31 error node v0.12.2
32 error npm v2.7.4
33 error code ECONNRESET
34 error network tunneling socket could not be established, cause=connect ECONNREFUSED
34 error network This is most likely not a problem with npm itself
34 error network and is related to network connectivity.
34 error network In most cases you are behind a proxy or have bad network settings.
34 error network
34 error network If you are behind a proxy, please make sure that the
34 error network 'proxy' config is set properly. See: 'npm help config'
35 verbose exit [ 1, true ]

I am not behind a proxy. Even tried using my mobile phone connection via hotspot, and same output.

Start by reproducing the npm install -g keybase-installer command with the reported Node.js v0.12.2 and npm 2.7.4 versions, then inspect the registry request and proxy configuration involved in the failure. Done would require identifying a reproducible project-side cause and confirming that installation succeeds without the reported tunneling error.