Use AddTagsToVault with an Amazon SDK or CLI

    /// <summary>
    /// Add tags to the items in an Amazon S3 Glacier vault.
    /// </summary>
    /// <param name="vaultName">The name of the vault to add tags to.</param>
    /// <param name="key">The name of the object to tag.</param>
    /// <param name="value">The tag value to add.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> AddTagsToVaultAsync(string vaultName, string key, string value)
    {
        var request = new AddTagsToVaultRequest
        {
            Tags = new Dictionary<string, string>
                {
                    { key, value },
                },
            AccountId = "-",
            VaultName = vaultName,
        };

        var response = await _glacierService.AddTagsToVaultAsync(request);
        return response.HttpStatusCode == HttpStatusCode.NoContent;
    }

The following command adds two tags to a vault named my-vault:

aws glacier add-tags-to-vault --account-id - --vault-name my-vault --tags id=1234,date=july2015

Amazon Glacier requires an account ID argument when performing operations, but you can use a hyphen to specify the in-use account.