> For the complete documentation index, see [llms.txt](https://docs.cloudtruth.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cloudtruth.com/configuration-management/parameters/rules-and-type.md). # Value Validation This, not that. Nobody enjoys typos, especially ones that make their way into production and cause outages. With CloudTruth you can set a series of rules and typing on your parameters to ensure they meet a specific criteria, or syntax, that meet specific intended values. ## Creating Parameter Rules Rules are set on the parameter itself within a selected project that provide validation of values across all of the parameters environments. The following are the current rules you can set on your parameters. | Parameter Type | Allowed Rules | | -------------- | ------------------------------------------------------------------- | | String |

Minimum Length

Maximum Length

Regular Expression

| | Integer |

Minimum

Maximum

| | Bool | Boolean Types | {% hint style="info" %} We provide a regular expression rule for strings to come up with whatever crafty regex you require. {% endhint %} The Type and Rules can be set during parameter creation or when editing a parameter.

Value typed is shorter than the minimum length

Value is longer than maximum allowed length

{% hint style="info" %} When adding rules to an existing parameter, CloudTruth will check across all environments to make sure the existing values conform to the new rule(s). If any of the values do *NOT* conform to the proposed rule change, the app will display the what and how the rule conflicts. Those conflicts will have to be remediated prior to setting the rule. {% endhint %}

Adding a rule to an existing parameter where an environment value does not match the rule

Error message when rule cannot be applied due to an existing value mismatch

The rule type and constraint settings are listed in the parameter's detail page for convenience.

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