user191: This is the main information post about our Maid Café (メイド喫茶) chat room's chat bots. Yes, chat bots are our new maid service.
The room currently has the following bots working:

Taisho

The room also at one point had:

HoiHoi-san
Karasu
Ruri


For a better experience, you might want to install:

Our famous StarScript!
Hide chat room description and tags so you can see more starred images on screen
Hide site logo and links from the bottom right corner and prevent chat input area from hogging horizontal space which obstructs the starred images


Basic bot information
This section contains information for users that are only interested in what they can get from the chat bots right now. If you're not a programmer or don't have any interest in the inner workings of bots, skip the Advances info section.
HoiHoi-san
She's our mechanical maid and the oldest non-human resident of the room (although we're not sure about some of our "users"). Her command calls start with !!.
Functions

!!Google something − Returns the first three results from Google search api;
!!Wiki something − Returns an article link if there was a match;
!!Define something − Returns the definition of a word or phrase on Wikitionary;

Taisho and Karasu
These two bonkuras are a cat and a crow with a red scarf that lets them speak in Japanese. We figured out how to translate most of their speech into English. They do essentially the same things. You can call them with the # prefix.
Functions

#post − Posts a picture of a cute girl, or even several. The cuteness varies from image to image. You can contribute to the image stash by asking the regulars in chat;
#unbox or #unonebox − As the name suggests, breaks the format of the last message required to onebox it by adding an ellipsis symbol … at the end of the message. This is useful for hiding image previews or very big oneboxes that clutter chat space;
#undo (also #Delete, #Remove) − Deletes last deletable message by bot. #Undo 4 − deleted 4 last messages. #Delete 1234567 − deletes bot's message with messageid 1234567. For obvious reasons, bot cannot delete any other user's messages like this. Only messages that have been posted no longer than 2 minutes ago can be deleted like this. If you are absolutely sure the message has to be deleted after this command stopped working, ask a moderator to delete it. 
#id link − Returns several image identification service links for the specified image link;
#isch link − Returns google image search link;
#last − Returns image ID links for the latest posted cute girl image. This service is one of the most popular, so naturally this command had to be implemented;
#alias − Adds, removes or lists command aliases. To add an alias, use #alias set <original command name> <new alias>. To remove an alias, use #alias remove <alias>. You cannot remove original commands like that, of course. To list all aliases for a specific command, use #alias list <original command name>.
#tag − Finds out who posted the last image, its tag, and when it was fed to Taisho.
#<unknown command> − Returns "I don't know this command" message. Due to incessant attempts to blame the developer for not adding a post command alias for all possible words, in conjunction with terrible attitude of the users and infinite laziness and unwillingness to accept all unknown commands as #post aliases, a new feature has been developed for easy aliasing. After receiving a response to an unknown command, press up arrow key and then send the exact same message (unedited) again. Bot will alias that command and post a picture simultaneously.

Ruri
Ruri would play text games with you, but now she's on a long journey overseas. We hope she comes back one day to make our daily lives a little better.

Advanced information
This section covers more of every bot's inner workings and explains how some of the more complex commands work.
HoiHoi-san
HoiHoi-san is based on a modified Zirak's chat bot. There are many chat rooms across StackExchange that use Zirak's bot as a base for their own. It's written in JavaScript and runs in a browser as a bookmarklet. It uses the browser as a way to communicate.
Currently @ton.yeung is developing a C# reimplementation of HoiHoi-san on Github.
Taisho
The chat users are controlled by a chat bot app developed by @Hakase. The app is written in C# and uses ChatExchange.Net to connect to chat and send/receive messages.
Image posting module (aka #post)
This module is set to automatically post images every 15 minutes. To be precise, after 15 minutes pass since the last image was posted by this module, it will start checking if 50 chat messages have been posted since the previous image was posted. Then, the module will wait 30 seconds since the last chat message to post the next image. This last interval is added to avoid interrupting a discussion with the large image.
Values in italic are variable and can be adjusted through following commands:

#post timeinterval T − Wait T minutes before checking if enough messages were posted;
#post postinterval P − Count P messages since the last image post;
#post waitinterval W − Wait W seconds after the latest chat message appeared in chat, after which the image will finally be posted.

But please don't edit these settings, it's been working just fine for the past 3 years.
Ruri
She was created by @Prix who generously left us his RuriLib, which is a chat interaction library, that the current SE Chat Bot App uses.

Feel free to update this meta post with the most complete information about our chat bots!
Please, send feature requests and bug reports to the chat bots' respective developers.

Also check out these SE chat API libraries:

ChatExchange for Python;
ChatExchange.Net for .NET languages;
JChatExchange for Java (still under development);
SE-Chatty for Ruby.


user191: How to add images to Taisho's list of unposted pictures:

Find an album of nice anime-related images. They must not break any SE rules like containing nudity and such. Preferably high resolution and quality. Just be sensible.
Upload those images on a reliable hosting and get direct links to them. Imgur is one valid choice.
Put all direct links to the images separated by new line into a .txt file or an online text hosting site like Pastebin. An example of text file contents:
http://i.imgur.com/VHllhiu.jpg
http://i.imgur.com/wWGuSnK.jpg
http://i.imgur.com/2QvNewu.png

Get link to the .txt file or raw version of online text hosting. If it's on Hastebin, it should look like this: http://hastebin.com/raw/asdfasdqwer.
Add images to Taisho like shown in these examples:
#post add http://example.com/images.txt
#post add http://pastebin.com/raw.php?i=_7a12H0_
#post add http://hastebin.com/raw/asdfasdqwer

(Optional) If you wish to add images with specific tags, add tag name after the link (separated by a space) like so:
#post add http://pastebin.com/raw.php?i=_7a12H0_ sometag

More on the image tags can be found in this post.


user191: Taisho can now post images with specific tags.
Syntax: #post <tag>
Example: #post wallpaper
If there are no more images in the specified tag unposted, Taisho will simply post a random picture out of all unposted links.
To add images with a specific tag to unposted link pool, append the tag name when adding link list. You can use as many tags as you think would be reasonable. 
Syntax: #post add <link> <tag_1> | <tag_2> | <tag_N>
Example: #post add http://pastebin.com/raw.php?i=ExAmPlE wallpaper | konosuba | megumin
To see the list of tagged links, use command #post tags.

Another way to add images with lots of different tags in a single text upload (apparently pastebin wants you to solve captchas for each uploaded text file, so this will help you speed things up):
link1
link2

tag1 | tag2 | tag3
link3
link4

tag4
link5

tag5 | tag6
link6
link7

The first section will be added without any tags, and the sections which are followed by a single line with tags delimited by | will be tagged as you would expect.

For your convenience, there are also image tag aliases. This means you can use different words to request images from the same tag.
To see what tag aliases are already set by users, say #post tag aliases
To add new tag alias, use #post tag <original tag name> = <new alias>
To remove an alias, use #post tag remove <alias>

191: <p>This is the main information post about our <a href="http://chat.stackexchange.com/rooms/6697/maid-cafe-">Maid Café (メイド喫茶) chat room</a>'s chat bots. Yes, chat bots are <em>our new maid service</em>.
The room currently has the following bots working:</p>

<ul>
<li><a href="http://chat.stackexchange.com/users/116952/taisho">Taisho</a></li>
</ul>

<p>The room also at one point had:</p>

<ul>
<li><a href="http://chat.stackexchange.com/users/106166/hoihoi-san">HoiHoi-san</a></li>
<li><a href="http://chat.stackexchange.com/users/123344/karasu">Karasu</a></li>
<li><a href="http://chat.stackexchange.com/users/122690/ruri">Ruri</a></li>
</ul>

<hr>

<h3>For a better experience, you might want to install:</h3>

<ul>
<li><a href="https://meta.stackexchange.com/questions/235178/move-onebox-images-to-separate-section-in-starred-message-list">Our famous StarScript!</a></li>
<li><a href="https://stackapps.com/questions/6237/remove-chat-room-description-and-tags">Hide chat room description and tags so you can see more starred images on screen</a></li>
<li><a href="https://stackapps.com/questions/6589/minimize-chat-input-area-%E2%88%92-remove-links-and-site-logo-no-auto-width">Hide site logo and links from the bottom right corner and prevent chat input area from hogging horizontal space which obstructs the starred images</a></li>
</ul>

<hr>

<h1>Basic bot information</h1>

<p>This section contains information for users that are only interested in what they can get from the chat bots right now. If you're not a programmer or don't have any interest in the inner workings of bots, skip the Advances info section.</p>

<h2>HoiHoi-san</h2>

<p>She's our mechanical maid and the oldest non-human resident of the room (although we're not sure about some of our "users"). Her command calls start with <code>!!</code>.</p>

<h3>Functions</h3>

<ul>
<li><code>!!Google something</code> − Returns the first three results from Google search api;</li>
<li><code>!!Wiki something</code> − Returns an article link if there was a match;</li>
<li><code>!!Define something</code> − Returns the definition of a word or phrase on Wikitionary;</li>
</ul>

<h2>Taisho <s>and Karasu</s></h2>

<p>These <s>two</s> bonkuras are a cat <s>and a crow</s> with a red scarf that lets them speak in Japanese. We figured out how to translate most of their speech into English. They do essentially the same things. You can call them with the <code>#</code> prefix.</p>

<h3>Functions</h3>

<ul>
<li><code>#post</code> − Posts a picture of a cute girl, or even several. The cuteness varies from image to image. You can contribute to the image stash by asking the regulars in chat;</li>
<li><code>#unbox</code> or <code>#unonebox</code> − As the name suggests, breaks the format of the last message required to onebox it by adding an ellipsis symbol <code>…</code> at the end of the message. This is useful for hiding image previews or very big oneboxes that clutter chat space;</li>
<li><code>#undo</code> (also <code>#Delete</code>, <code>#Remove</code>) − Deletes last deletable message by bot. <code>#Undo 4</code> − deleted 4 last messages. <code>#Delete 1234567</code> − deletes bot's message with messageid 1234567. For obvious reasons, bot cannot delete any other user's messages like this. Only messages that have been posted no longer than 2 minutes ago can be deleted like this. If you are absolutely sure the message has to be deleted after this command stopped working, ask a moderator to delete it. </li>
<li><code>#id link</code> − Returns several image identification service links for the specified image link;</li>
<li><code>#isch link</code> − Returns google image search link;</li>
<li><code>#last</code> − Returns image ID links for the latest posted cute girl image. This service is one of the most popular, so naturally this command had to be implemented;</li>
<li><code>#alias</code> − Adds, removes or lists command aliases. To add an alias, use <code>#alias set &lt;original command name&gt; &lt;new alias&gt;</code>. To remove an alias, use <code>#alias remove &lt;alias&gt;</code>. You cannot remove original commands like that, of course. To list all aliases for a specific command, use <code>#alias list &lt;original command name&gt;</code>.</li>
<li><code>#tag</code> − Finds out who posted the last image, its tag, and when it was fed to Taisho.</li>
<li><code>#&lt;unknown command&gt;</code> − Returns "I don't know this command" message. Due to incessant attempts to blame the developer for not adding a <code>post</code> command alias for all possible words, in conjunction with terrible attitude of the users and infinite laziness and unwillingness to accept all unknown commands as <code>#post</code> aliases, a new feature has been developed for easy aliasing. After receiving a response to an unknown command, press <em>up arrow key</em> and then send the exact same message (unedited) again. Bot will alias that command and post a picture simultaneously.</li>
</ul>

<h2>Ruri</h2>

<p>Ruri would play text games with you, but now she's on a long journey overseas. We hope she comes back one day to make our daily lives a little better.</p>

<hr>

<h1>Advanced information</h1>

<p>This section covers more of every bot's inner workings and explains how some of the more complex commands work.</p>

<h2>HoiHoi-san</h2>

<p>HoiHoi-san is based on a modified <a href="https://github.com/Zirak/SO-ChatBot" rel="nofollow noreferrer">Zirak's chat bot</a>. There are many chat rooms across StackExchange that use Zirak's bot as a base for their own. It's written in JavaScript and runs in a browser as a bookmarklet. It uses the browser as a way to communicate.</p>

<p>Currently @ton.yeung is developing a <a href="https://github.com/tonyeung/Stack-Exchange-Chat-Bot" rel="nofollow noreferrer">C# reimplementation of HoiHoi-san on Github</a>.</p>

<h2>Taisho</h2>

<p>The chat users are controlled by a chat bot app developed by <a href="http://chat.stackexchange.com/users/36474/hakase">@Hakase</a>. The app is written in C# and uses ChatExchange.Net to connect to chat and send/receive messages.</p>

<h3>Image posting module (aka #post)</h3>

<p>This module is set to automatically post images every <em>15</em> minutes. To be precise, after <em>15</em> minutes pass since the last image was posted by this module, it will start checking if <em>50</em> chat messages have been posted since the previous image was posted. Then, the module will wait <em>30</em> seconds since the last chat message to post the next image. This last interval is added to avoid interrupting a discussion with the large image.</p>

<p>Values in <em>italic</em> are variable and can be adjusted through following commands:</p>

<ul>
<li><code>#post timeinterval T</code> − Wait <strong>T</strong> minutes before checking if enough messages were posted;</li>
<li><code>#post postinterval P</code> − Count <strong>P</strong> messages since the last image post;</li>
<li><code>#post waitinterval W</code> − Wait <strong>W</strong> seconds after the latest chat message appeared in chat, after which the image will finally be posted.</li>
</ul>

<p>But please don't edit these settings, it's been working just fine for the past 3 years.</p>

<h2>Ruri</h2>

<p>She was created by @Prix who generously left us his RuriLib, which is a chat interaction library, that the current SE Chat Bot App uses.</p>

<hr>

<p>Feel free to update this meta post with the most complete information about our chat bots!</p>

<p>Please, send feature requests and bug reports to the chat bots' respective developers.</p>

<hr>

<p>Also check out these SE chat API libraries:</p>

<ul>
<li><a href="https://github.com/Manishearth/ChatExchange" rel="nofollow noreferrer">ChatExchange</a> for Python;</li>
<li><a href="https://github.com/ArcticEcho/ChatExchange.Net" rel="nofollow noreferrer">ChatExchange.Net</a> for .NET languages;</li>
<li><a href="https://github.com/Vincentyification/JChatExchange" rel="nofollow noreferrer">JChatExchange</a> for Java (still under development);</li>
<li><a href="https://github.com/KeyboardFire/stackexchange-chatty" rel="nofollow noreferrer">SE-Chatty</a> for Ruby.</li>
</ul>
 191: <p>How to add images to Taisho's list of unposted pictures:</p>

<ol>
<li><p>Find an album of nice anime-related images. They must not break any SE rules like containing nudity and such. Preferably high resolution and quality. Just be sensible.</p></li>
<li><p>Upload those images on a reliable hosting and get direct links to them. Imgur is one valid choice.</p></li>
<li><p>Put all direct links to the images separated by new line into a .txt file or an online text hosting site like Pastebin. An example of text file contents:</p>

<pre><code>http://i.imgur.com/VHllhiu.jpg
http://i.imgur.com/wWGuSnK.jpg
http://i.imgur.com/2QvNewu.png
</code></pre></li>
<li><p>Get link to the .txt file or raw version of online text hosting. If it's on Hastebin, it should look like this: <code>http://hastebin.com/raw/asdfasdqwer</code>.</p></li>
<li><p>Add images to Taisho like shown in these examples:</p>

<pre><code>#post add http://example.com/images.txt
#post add http://pastebin.com/raw.php?i=_7a12H0_
#post add http://hastebin.com/raw/asdfasdqwer
</code></pre></li>
<li><p>(Optional) If you wish to add images with specific tags, add tag name after the link (separated by a space) like so:</p>

<pre><code>#post add http://pastebin.com/raw.php?i=_7a12H0_ sometag
</code></pre>

<p>More on the image tags can be found in <a href="https://anime.meta.stackexchange.com/a/2362/191">this post</a>.</p></li>
</ol>
 191: <p>Taisho can now post images with specific tags.</p>

<p>Syntax: <code>#post &lt;tag&gt;</code></p>

<p>Example: <code>#post wallpaper</code></p>

<p>If there are no more images in the specified tag unposted, Taisho will simply post a random picture out of all unposted links.</p>

<p>To add images with a specific tag to unposted link pool, append the tag name when adding link list. You can use as many tags as you think would be reasonable. </p>

<p>Syntax: <code>#post add &lt;link&gt; &lt;tag_1&gt; | &lt;tag_2&gt; | &lt;tag_N&gt;</code></p>

<p>Example: <code>#post add http://pastebin.com/raw.php?i=ExAmPlE wallpaper | konosuba | megumin</code></p>

<p>To see the list of tagged links, use command <code>#post tags</code>.</p>

<hr>

<p>Another way to add images with lots of different tags in a single text upload (apparently pastebin wants you to solve captchas for each uploaded text file, so this will help you speed things up):</p>

<pre><code>link1
link2

tag1 | tag2 | tag3
link3
link4

tag4
link5

tag5 | tag6
link6
link7
</code></pre>

<p>The first section will be added without any tags, and the sections which are followed by a single line with tags delimited by <code>|</code> will be tagged as you would expect.</p>

<hr>

<p>For your convenience, there are also image tag aliases. This means you can use different words to request images from the same tag.</p>

<p>To see what tag aliases are already set by users, say <code>#post tag aliases</code></p>

<p>To add new tag alias, use <code>#post tag &lt;original tag name&gt; = &lt;new alias&gt;</code></p>

<p>To remove an alias, use <code>#post tag remove &lt;alias&gt;</code></p>
