Every Odoo module has a manifest, and the manifest is what makes the module a module Odoo can use. Getting it right is essential. This piece is about writing a correct manifest.
What the manifest does
The manifest is the file that describes a module: it gives the module's name and information about it, it declares what the module depends on, and it declares which of the module's files Odoo should load. The manifest is, in essence, how Odoo knows the module exists and what it consists of. Without a correct manifest, Odoo cannot genuinely use the module.
The dependencies
An important part of the manifest is the declaration of what the module depends on. A module almost always builds on other modules, it extends them, it uses what they provide, and the manifest has to declare those modules the module genuinely depends on. Getting the dependencies right matters: if a module's manifest does not declare a module it genuinely depends on, the module is not correctly built, it is relying on something it has not declared it needs. Writing a correct manifest means genuinely declaring the module's real dependencies.
The files to load
The other central part of the manifest is the declaration of which files Odoo should load. A module's functionality is in its files, the views, the security, the data, and the manifest has to declare the files Odoo should load for the module. This is a place where errors genuinely happen: a file that is part of the module but not declared in the manifest is not loaded, and the module is then missing what that file would have provided, often silently. Writing a correct manifest means genuinely declaring all the files Odoo should load, so the module loads completely.
Why getting the manifest right is essential
Getting the manifest right is essential because the manifest is what makes the module load, and load completely and correctly. A manifest that is wrong, a missed dependency, a file not declared, means the module does not genuinely work as it should: it may not load, or it loads incompletely, missing what an undeclared file would have provided. And a module loading incompletely because of a manifest error can be a confusing fault, the module seems to be there but something is missing. So the manifest, modest as it is, has to be genuinely correct, because the whole module's loading depends on it.
Write the manifest carefully and keep it current
The practical guidance is to write the manifest carefully, genuinely declaring the module's real dependencies and all the files to load, and to keep it current as the module changes. When a file is added to the module, the manifest has to be updated to declare it; when a dependency changes, the manifest has to reflect it. A correct manifest is one that genuinely and currently describes the module, and keeping it correct is an ongoing part of developing the module.
The takeaway
Writing a correct manifest in Odoo is essential, because the manifest is what makes a module a module Odoo can genuinely use: it describes the module, declares its dependencies, and declares the files Odoo should load. Getting the manifest right means genuinely declaring the module's real dependencies and all the files to load, since a missed dependency or an undeclared file means the module does not work completely. Write the manifest carefully and keep it current as the module changes. For how we approach Odoo, see our ERP practice.