`Discover`

What it does

Discover runs monochange package discovery and renders the result in text or json form.

It is the step to use when you want to inspect how monochange sees the repository before you involve changesets or release logic.

Why use it

Use Discover when you need visibility into:

which packages monochange found
which ids were assigned
which manifest paths were normalized
whether a repository layout is discoverable the way you expect

This is particularly valuable in mixed-ecosystem monorepos where discovery rules are part of the product contract.

Step-level `when` condition

All CLI steps support an optional when = "..." condition.

If the expression resolves to false at runtime, monochange skips the step and continues with the next step.

when = "{{ inputs.enabled }}"

Step-level `always_run` flag

All CLI steps support an optional always_run = true flag.

When set, the step executes even if a previous step in the same command has failed. This is useful for cleanup, notification, or dry-run preview steps that must run regardless of earlier outcomes.

always_run = true

Side effects and outputs

discovers packages across supported ecosystems
emits a report for the overall CLI command output
does not prepare release state for later steps

Example

[cli.discover]
help_text = "Discover packages across supported ecosystems"

[[cli.discover.inputs]]
name = "format"
type = "choice"
choices = ["text", "json"]
default = "text"

[[cli.discover.steps]]
type = "Discover"
inputs = ["format"]

Composition ideas

Discovery-focused debug command

[cli.discover-debug]
help_text = "Show package discovery and then print a custom notice"

[[cli.discover-debug.inputs]]
name = "format"
type = "choice"
choices = ["text", "json"]
default = "json"

[[cli.discover-debug.steps]]
type = "Discover"

Discover is usually best as the only step in a command, because its value is the rendered report itself.

Use it during repository setup

During initial adoption, teams often expose a discover command next to validate so contributors can see the exact package ids they should use in .changeset/*.md files and command inputs.

A Command step that runs mc discover works, but the built-in step is easier to validate and easier to understand when reading monochange.toml. It makes the intent obvious: the command exists to inspect discovery, not to run an arbitrary shell pipeline.

Common mistake

Do not treat Discover as release planning. It does not read changesets into a release decision. For that, use PrepareRelease.

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