# chainctl images overlays attach

URL: https://chainguard-docs-preview-git-exp-577-mcp-refuse-sse-get.chainguard.app/platform/chainctl/chainctl-docs/chainctl_images_overlays_attach.md
Last Modified: October 8, 2026
Tags: chainctl, Reference, Product

 chainctl images overlays attach Attach Custom Assembly overlays to a repo or to every repo in an organization.
Synopsis Attach one or more Custom Assembly overlays by creating a binding per overlay. A binding attaches an overlay to a single repo (–repo) or to every repo in an organization (–all-repos), including repos created after the binding exists.
Every binding selects which tags its overlay applies to. Pass exactly one of:
–all: every tag. –variant: a tag variant, such as dev. –tag: specific tags. A repo can hold several bindings of the same kind only when their overlays do not conflict; a conflicting binding is rejected, and the error names the conflicting binding and fields. An overlay can be attached to a repo only once. Multiple overlays attach in the order given, one binding each; on a failure, the bindings already created are kept and the error names the overlay that failed.
An all-repos binding is owned by the organization and applies its overlay to each repo’s matching tags. An overlay can have at most one all-repos binding per organization. When an all-repos binding and a repo’s own binding match the same tag, the repo’s binding takes precedence where both overlays set the same field, and their package lists combine. Repos with a legacy customization keep the legacy behavior; all-repos bindings do not apply to them.
The command prints each binding UID. Use them with “update-binding” and “detach”, or look them up later with “chainctl images overlays list”.
chainctl images overlays attach [flags] Examples # Apply an overlay to every tag of a repo chainctl images overlays attach --overlay my-overlay --repo python --parent my-org --all # Apply an overlay to every tag of every repo in the organization, # including repos created later chainctl images overlays attach --overlay my-overlay --all-repos --parent my-org --all # Apply two overlays to every tag of a repo chainctl images overlays attach --overlay my-certs,my-packages --repo python --parent my-org --all # Apply an overlay to -dev tags only chainctl images overlays attach --overlay my-overlay --repo python --parent my-org --variant dev # Apply an overlay to specific tags chainctl images overlays attach --overlay my-overlay --repo python --parent my-org --tag 3.12 --tag 3.13 Options --all Bind to every tag on the repo; multiple --all bindings may coexist when their overlays do not conflict. Mutually exclusive with --tag and --variant. --all-repos Attach to every repo in the organization, including repos created later; mutually exclusive with --repo. --overlay strings Overlay to attach: UIDP or name (resolved within the repo's org). Comma separated and repeatable; each overlay gets its own binding with the same tag selector. --parent string Org name or UIDP: the organization the binding is created under with --all-repos, or the org for resolving --repo by name (unused when --repo is a UIDP). If unset, auto-selects when the caller belongs to a single org, otherwise prompts. Defaults to the default.group config value (env: CHAINGUARD_DEFAULT_GROUP). --repo string Target repo: UIDP, or name resolved within --parent. Mutually exclusive with --all-repos. --tag strings Exact tag names to bind to (repeatable). Mutually exclusive with --all and --variant. "all" and "dev" are not tags: use --all or --variant=dev. --variant string Bind to a tag variant: currently only "dev" (matches tags ending in -dev). Mutually exclusive with --tag and --all. Options inherited from parent commands --api string The url of the Chainguard platform API. (default "https://console-api.enforce.dev") --audience string The Chainguard token audience to request. (default "https://console-api.enforce.dev") --config string A specific chainctl config file. Uses CHAINCTL_CONFIG environment variable if a file is not passed explicitly. --console string The url of the Chainguard platform Console. (default "https://console.chainguard.dev") --force-color Force color output even when stdout is not a TTY. -h, --help Help for chainctl --issuer string The url of the Chainguard STS endpoint. (default "https://issuer.enforce.dev") --log-level string Set the log level (debug, info) (default "ERROR") -o, --output string Output format. One of: [csv, env, go-template, id, json, markdown, none, table, terse, tree, wide] -v, --v int Set the log verbosity level. SEE ALSO chainctl images overlays	- Manage Custom Assembly overlays and the repos they are attached to.