Why am I getting "Failed to load extension. Invalid value for 'content_security_policy'"?

Question

I am trying to create a chrome extension. My manifest file is

{
    "name": "Alert-Beep",
    "action": {},
    "manifest_version": 3,
    "version": "0.1",
    "description": "Beeps if alert() is called",
    "content_security_policy": "script-src 'self'; object-src 'self'",
    "permissions": [
    "activeTab",
    "scripting"
    ],
    "content_scripts": [
    {
        "matches": ["https://*.com/*"],
        "js": ["alert-beep.js"],
        "run_at": "document_start"
    }
    ]
}

Loading the extension fails with the message

Failed to load extension
File
~\alert-beep
Error
Invalid value for 'content_security_policy'.
Could not load manifest.

What am I doing wrong?

See the [migration guide](https://developer.chrome.com/docs/extensions/mv3/intro/mv3-migration/#fcontent-security-policy): CSP is now a dictionary object. — wOxxOm, Apr 17 '21 at 02:51
Thanks. I also found this answer to be helpful https://stackoverflow.com/questions/63308160/how-to-migrate-manifest-version-2-to-v3-for-chrome-extension — DeLorean88, Apr 17 '21 at 14:30

score 21 · Accepted Answer · edited Jan 18 '22 at 05:57

21

An additional example that helped me:

manifest v3

"content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'; script-src-elem 'self' 'unsafe-inline' https://music.yandex.ru/;"
}

edited Jan 18 '22 at 05:57

Chris McFarland

6,059
5
43
63

answered Aug 11 '21 at 23:14

Илья Хоришко

695
4
15

Where can I find the docs talking about this? – AlwaysLearning Jul 20 '23 at 11:05

score 5 · Answer 2 · answered Jul 15 '21 at 14:45

5

I've looked into CSP for chrome extensions (go here to learn more for manifest v3).

Use

"content_security_policy": {
  "extension_pages": "script-src 'self'; object-src 'self'"
}

answered Jul 15 '21 at 14:45

M2K Developments

86
1
3

score 1 · Answer 3 · answered Feb 03 '22 at 07:36

Since manifest is now updated to V3, content_security_policy is a dictionary. in this case, you should change this line

"content_security_policy": "script-src 'self'; object-src 'self'",

to this

"content_security_policy": {
    "script-src": 'self',
    "object-src": 'self'
 }

read more here: https://developer.chrome.com/docs/extensions/mv3/intro/mv3-migration/#content-security-policy

Why am I getting "Failed to load extension. Invalid value for 'content_security_policy'"?

3 Answers3

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