> ## Documentation Index
> Fetch the complete documentation index at: https://kosli-reference-docs-v2-30-1.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# kosli evaluate trail

> Evaluate a trail against a policy.

<Warning>
  This is a beta feature. Beta features provide early access to product
  functionality. These features may change between releases without warning, or
  can be removed in a future release. Please contact us to enable this feature
  for your organization.
</Warning>

## Synopsis

```shell theme={null}
kosli evaluate trail TRAIL-NAME [flags]
```

Evaluate a trail against a policy.
Fetch a single trail from Kosli and evaluate it against a Rego policy.
The trail data is passed to the policy as `input.trail`.

Use `--attestations` to enrich the input with detailed attestation data
(e.g. pull request approvers, scan results). Use `--show-input` to inspect the
full data structure available to the policy. Use `--output json` for structured output.

## Flags

| Flag                     | Description                                                                                                                                        |
| :----------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------- |
| `--assert`               | \[optional] Exit with a non-zero status when the policy denies. This is the current default; pass `--assert` to lock it in across future releases. |
| `--attestations` strings | \[optional] Limit which attestations are included. Plain name for trail-level, dot-qualified (artifact.name) for artifact-level.                   |
| `-f`, `--flow` string    | The Kosli flow name.                                                                                                                               |
| `-h`, `--help`           | help for trail                                                                                                                                     |
| `--no-assert`            | \[optional] Print the result and always exit 0, even when the policy denies. Use when this command feeds another tool as a policy decision point.  |
| `-o`, `--output` string  | \[defaulted] The format of the output. Valid formats are: \[table, json]. (default "table")                                                        |
| `--params` string        | \[optional] Policy parameters as inline JSON or @file.json. Available in policies as data.params.                                                  |
| `-p`, `--policy` string  | Path or http(s):// URL of a Rego policy to evaluate against the trail.                                                                             |
| `--show-input`           | \[optional] Include the policy input data in the output.                                                                                           |

## Flags inherited from parent commands

| Flag                          | Description                                                                                                                                             |
| :---------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `-a`, `--api-token` string    | The Kosli API token.                                                                                                                                    |
| `-c`, `--config-file` string  | \[optional] The Kosli config file path. (default "kosli")                                                                                               |
| `--debug`                     | \[optional] Print debug logs to stdout.                                                                                                                 |
| `-H`, `--host` string         | \[defaulted] The Kosli endpoint. (default "[https://app.kosli.com](https://app.kosli.com)")                                                             |
| `--http-proxy` string         | \[optional] The HTTP proxy URL including protocol and port number. e.g. `http://proxy-server-ip:proxy-port`                                             |
| `-r`, `--max-api-retries` int | \[defaulted] How many times should API calls be retried when the API host is not reachable. (default 3)                                                 |
| `--org` string                | The Kosli organization.                                                                                                                                 |
| `-q`, `--quiet`               | \[optional] Suppress non-critical warning messages. Errors and normal output are not affected. If both `--quiet` and `--debug` are set, `--debug` wins. |

## Live Examples in different CI systems

<Tabs>
  <Tab title="GitHub">
    View an example of the `kosli evaluate trail` command in GitHub.

    In [this YAML file](https://github.com/cyber-dojo/snyk-scanning/blob/a517304f4e9013e2e9ea67e90c7342f7e56653f0/.github/workflows/artifact_snyk_test.yml#L323)
  </Tab>
</Tabs>

## Examples Use Cases

These examples all assume that the flags  `--api-token`, `--org`, `--host`, (and `--flow`, `--trail` when required), are [set/provided](/getting_started/install/#assigning-flags-via-environment-variables).

<AccordionGroup>
  <Accordion title="evaluate a trail against a policy">
    ```shell theme={null}
    kosli evaluate trail yourTrailName 
    	--policy yourPolicyFile.rego 

    ```
  </Accordion>

  <Accordion title="evaluate a trail with attestation enrichment">
    ```shell theme={null}
    kosli evaluate trail yourTrailName 
    	--policy yourPolicyFile.rego 
    	--attestations pull-request 

    ```
  </Accordion>

  <Accordion title="evaluate a trail and show the policy input data">
    ```shell theme={null}
    kosli evaluate trail yourTrailName 
    	--policy yourPolicyFile.rego 
    	--show-input 
    	--output json 

    ```
  </Accordion>

  <Accordion title="evaluate a trail with policy parameters (inline JSON)">
    ```shell theme={null}
    kosli evaluate trail yourTrailName 
    	--policy yourPolicyFile.rego 
    	--params '{"min_approvers": 2}' 

    ```
  </Accordion>

  <Accordion title="evaluate a trail with policy parameters from a file">
    ```shell theme={null}
    kosli evaluate trail yourTrailName 
    	--policy yourPolicyFile.rego 
    	--params @params.json 

    ```
  </Accordion>

  <Accordion title="evaluate a trail using a policy fetched from a remote URL">
    ```shell theme={null}
    kosli evaluate trail yourTrailName 
    	--policy https://policies.example.com/trail.rego 

    ```
  </Accordion>

  <Accordion title="evaluate a trail as a decision point (print verdict, never fail the step)">
    ```shell theme={null}
    kosli evaluate trail yourTrailName 
    	--policy yourPolicyFile.rego 
    	--no-assert 
    ```
  </Accordion>
</AccordionGroup>