# Features

## Plugin-aware completion

conda-completion introspects conda's full argparse tree after all plugins
have loaded. Every plugin that registers subcommands via
{external+conda:doc}`conda_subcommands <dev-guide/plugins/subcommands>`
is included when the manifest is generated. No conda-completion-specific
configuration is required.

Installed plugin commands use the same manifest format as built-in
commands: subcommands, flags, flag values, and help descriptions.

## Contextual completions

The completer reads your project files to provide context-aware candidates:

`environment.yml` is the established conda environment file. `conda.toml`
support follows the emerging workspace manifest used by
[conda-workspaces](https://github.com/conda-incubator/conda-workspaces);
it is not a formal conda standard.

| What's completed | Source files |
|---|---|
| Environment names | `conda.toml`, `pixi.toml`, `pyproject.toml`, `environment.yml`, `conda.lock`, `pixi.lock`, `anaconda-project.yml`, `conda-project.yml`, `~/.conda/environments.txt` |
| Task names | `conda.toml`, `pixi.toml`, `pyproject.toml`, `anaconda-project.yml`, `conda-project.yml` |
| Channel names | `conda.toml`, `pixi.toml`, `pyproject.toml`, `conda-lock.yml`, `conda.lock`, `pixi.lock`, `.condarc` |

## Descriptions alongside candidates

In shells that support it (zsh, fish, PowerShell), each candidate is shown
with its help text:

:::{image} ../demos/option-completion.gif
:alt: Option completion with descriptions
:width: 100%
:::

```text
$ conda install --<TAB>
--channel     -- Additional channel to search for packages
--dry-run     -- Only display what would have been done
--name        -- Name of environment
--prefix      -- Full path to environment location
```

## Package name completion

`conda install nump<TAB>` completes package names extracted from
configured channels during `conda completion generate`.

:::{image} ../demos/package-completion.gif
:alt: Package name completion from conda repodata
:width: 100%
:::

## Version completion

When `=` or `==` is detected in the current word, the completer loads
version data and lists available versions:

```text
$ conda install numpy=<TAB>
numpy=1.26.4  numpy=2.0.0  numpy=2.1.0  ...
```

Version data is stored in an indexed `versions.index` and `versions.store`
pair that is only loaded when needed, keeping the common TAB press fast.

## Fuzzy matching

Misspelled a package name? The completer falls back to fuzzy matching
using normalized Damerau-Levenshtein similarity. Typos like `numpie`,
`nupmy`, or `scikitlearn` still find the right package.

:::{image} ../demos/fuzzy-matching.gif
:alt: Fuzzy package matching demo
:width: 100%
:::

The matching uses a three-stage strategy:

1. **Prefix match** -- the common case, essentially free
2. **Substring match** -- catches partial input anywhere in the name
3. **Similarity match** -- handles typos (transpositions, insertions,
   deletions, substitutions) with a 0.6 threshold, capped at 10 results

## No Python on TAB press

A Rust binary handles every TAB press. No Python process starts on the
hot path. A stat-based file cache avoids re-parsing project files that
have not changed since the last keypress.

## Automatic manifest regeneration

After `conda install`, `conda remove`, or `conda update`, a post-command
hook checks whether the set of registered conda plugin entry point names
has changed. If it has, the completion manifest is regenerated
automatically. Manual regeneration is needed for plugins installed outside
conda's package manager, and after plugin updates that change command
metadata without changing entry point names.

## Repodata controls

Package metadata is reused for 24 hours by default. Run
`conda completion refresh` when you want conda-completion to rebuild its
package list now, or `conda completion generate --no-repodata` when you
only need command, flag, plugin, and contextual completions.

## Shell support

| Shell | Notes |
|---|---|
| bash | Supported and covered by automated tests |
| zsh | Supported and covered by automated tests |
| PowerShell | Supported and covered by automated tests |
| fish | Supported and covered by automated tests |

## Install and uninstall commands

`conda completion install` and `conda completion uninstall` manage a
delimited block in your shell's RC file. The install command is
idempotent (running it twice does not duplicate the block) and supports
`--dry-run` to preview changes without writing.