'Texas Hold Em Poker' Agent Heuristics to help decide whether to fold or bet?
Here are some of the heuristics I use when playing online on XBOX live against bots, but the game is so much better with human players, bots are boring and predictable.


Obviously, what are you hold cards. Rockets to 7-2 off suite. There are many poker tables that give you the odds for the hold cards.
How many players at the table. The more players you have the better your hand has to be because more cards are in play for making better hands. When you get down to one-on-one, even a high card is often good, but with a table of 10, you should be holding at least a high pair after the river.
Is the card generator truly random. For the XBOX live games it is rumored they use a card generator named the "Action Engine" because it is designed to generate action on the table by setting up possible flushes and straights. You would not believe how many people chase down the river hoping for a straight or flush, problem is they tend to get it more often than random because of the simulated gambling.
Is there a pattern to the players betting? Do they continue to bet on each card? Do they slow play when then have a good hand or the nuts? Do they bet really big when bluffing? Do the bet really big when they have a high card or better? I their betting related to the the cards they have? Do they ever bluff?
Are you allowed to keep a database of all hands? This is a big advantage if allowed.
Position. Are you the dealer or in the blind? Ever heard the saying that poker is a game of position.
Does a player re-raise?
Does a player fold before or on the river to hide their cards if they don't believe they have a good hand even if they can check?
Do they play most hands or are conservative. A conservative player will bet only on good cards and you can pretty much count on that, while a player who plays most to all hands means that you have to more attentive to them having the nuts from the flop no matter what the flop is.
Does the player have a limit they never bet or raise beyond?
How many out cards do you have versus all of the possible out cards. 
Does the player play the heavy? At what level will they play the heavy against another player?
Is the player afraid to call an all-in. 
Is there a level below they will not raise? I.e. only raise if a King or higher in their hold cards, or have a pair or higher with what's on the table?
Do they go all in if the best hand can only be made by the cards on the table?
Do they bluff more when A's, or possible straights or flushes appear?
Is there betting based on money amounts or multiples of the blind?
Does there style of play changed based on their money amount? Based on a multiple of the blind? Based on who sits next to them?
Can you use the length of time the opponent uses to play a turn to your advantage?
Is the player trying to win the game or just play to make it to the money rounds?
Are the players susceptible to being pulled into betting wars?
Can betting big on the river cause the player to fold more than normal?
Can always re-raising a player get them to change their playing style?
Are their bet amounts increasing or decreasing as the hand progresses?
Is there a minimum amount they always bet no matter what they have in the hold?


These are just the basic ones for playing a bot, if you add a human player the list of heuristics gets much more complicated.