Cache list JSON#

conda exec --list --json prints machine-readable cache metadata when cached environments exist.

conda exec --list --json

The standalone alias has the same output:

ce --list --json

Output shape#

The output is a JSON array. Each item describes one cached environment:

[
  {
    "tool": "ruff",
    "key": "ruff--a3f8b2c140d91a4e",
    "prefix": "/Users/alice/.conda/exec/envs/ruff--a3f8b2c140d91a4e",
    "created": "2026-05-28T09:15:23.123456+00:00",
    "last_used": "2026-05-28T10:42:01.987654+00:00",
    "size_bytes": 44983910,
    "packages": 3
  }
]

Fields#

tool: The tool portion of the cache key. Tool environments use the package name, and script environments use script.
key: The full cache key, including the hash suffix.
prefix: Absolute path to the cached conda prefix.
created: ISO 8601 timestamp from conda’s prefix metadata, or null when the creation time is unavailable.
last_used: ISO 8601 timestamp from conda’s prefix metadata, or null when the timestamp is unavailable. conda-exec updates the environment history mtime on cache hits with a one-hour debounce.
size_bytes: Size of the prefix in bytes as reported by conda’s PrefixData.
packages: Number of package records in the environment.

Empty cache behavior#

When no cached environments exist, the command prints the same text as the table output:

No cached environments.

Do not assume empty output is valid JSON. If a script needs to handle both cases, treat this exact message as an empty list or ensure at least one cache entry exists before consuming JSON.

Relationship to conda JSON mode#

Use the local --json flag with --list. conda-exec’s list output is not currently controlled by conda’s global CONDA_JSON setting.

--json is only meaningful with --list. Passing it to a normal tool or script run prints a warning and continues without changing the tool output.