diff --git a/_data-prepper/pipelines/configuration/processors/anomaly-detector.md b/_data-prepper/pipelines/configuration/processors/anomaly-detector.md
index 9628bb6caf..333245f0e3 100644
--- a/_data-prepper/pipelines/configuration/processors/anomaly-detector.md
+++ b/_data-prepper/pipelines/configuration/processors/anomaly-detector.md
@@ -53,6 +53,7 @@ You can configure `random_cut_forest` mode with the following options.
 | `sample_size` | `256` | 100--2500 | The sample size used in the ML algorithm. |
 | `time_decay` | `0.1` | 0--1.0 | The time decay value used in the ML algorithm. Used as the mathematical expression `timeDecay` divided by `SampleSize` in the ML algorithm. |
 | `type` | `metrics` | N/A | The type of data sent to the algorithm. |
+| `output_after` | 32 | N/A | Indicates the number of events to consume before outputting anamolies |
 | `version` | `1.0` | N/A | The algorithm version number. |
 
 ## Usage
diff --git a/_data-prepper/pipelines/expression-syntax.md b/_data-prepper/pipelines/expression-syntax.md
index 383b54c19b..266e96b02b 100644
--- a/_data-prepper/pipelines/expression-syntax.md
+++ b/_data-prepper/pipelines/expression-syntax.md
@@ -30,6 +30,9 @@ The following table lists the supported operators. Operators are listed in order
 |----------------------|-------------------------------------------------------|---------------|
 | `()`                 | Priority expression                                   | Left to right |
 | `not`<br> `+`<br>  `-`| Unary logical NOT<br>Unary positive<br>Unary negative | Right to left |
+| `*`, `/`             | Multiplication and division operators                 | Left to right |
+| `+`, `-`             | Addition and subtraction operators                    | Left to right |
+| `+`                  | String concatenation operator                         | Left to right |
 | `<`, `<=`, `>`, `>=` | Relational operators                                  | Left to right |
 | `==`, `!=`           | Equality operators                                    | Left to right |
 | `and`, `or`          | Conditional expression                                | Left to right |
@@ -78,7 +81,6 @@ Conditional expressions allow you to combine multiple expressions or values usin
 <Any> or <Any>
 not <Any>
 ```
-{% include copy-curl.html %}
 
 The following are some example conditional expressions: 
 
@@ -91,9 +93,64 @@ not /status_code in {200, 202}
 ```
 {% include copy-curl.html %}
 
+### Arithmetic expressions
+
+Arithmetic expressions allow you to do few basic arithmetic operations. Arithmetic expressions may be combined with conditional expressions to make more complex conditional expressions. The available arithmetic operators are `+`, `-`, `*`, and `/` for doing addition, subtraction, multiplication and division respectively. The syntax for using the arithmetic operators is as follows:
+
+```
+<Any> + <Any>
+<Any> - <Any>
+<Any> * <Any>
+<Any> / <Any>
+```
+
+The following are some example arithmetic expressions: 
+
+```
+/value + length(/message)
+/bytes / 1024
+/value1 - /value2
+/TimeInSeconds * 1000
+```
+{% include copy-curl.html %}
+
+The following are some example arithmetic expressions used in conditional expressions : 
+
+```
+/value + length(/message) > 200
+/bytes / 1024 < 10
+/value1 - /value2 != /value3 + /value4
+```
+{% include copy-curl.html %}
+
+### String concatenation expressions
+
+String concatenation expressions allow you to concatenate strings to generate new strings. The concatenated strings can be used in conditional expressions too. The syntax for using string concatenation is as follows:
+
+```
+<String Variable or String Literal> + <String Variable or String Literal>
+```
+
+The following are some example string concatenation expressions:
+
+```
+/name + "suffix"
+"prefix" + /name
+"time of " + /timeInMs + " ms"
+```
+{% include copy-curl.html %}
+
+The following are some example string concatenation expressions used in conditional expressions :
+
+```
+/service + ".com" == /url
+"www." + /service != /url
+```
+{% include copy-curl.html %}
+
 ### Reserved symbols
 
-Reserved symbols are symbols that are not currently used in the expression syntax but are reserved for possible future functionality or extensions. Reserved symbols include `^`, `*`, `/`, `%`, `+`, `-`, `xor`, `=`, `+=`, `-=`, `*=`, `/=`, `%=`, `++`, `--`, and `${<text>}`.
+Reserved symbols are symbols that are not currently used in the expression syntax but are reserved for possible future functionality or extensions. Reserved symbols include `^`, `%`, `xor`, `=`, `+=`, `-=`, `*=`, `/=`, `%=`, `++`, `--`, and `${<text>}`.
 
 ## Syntax components
 
@@ -170,6 +227,9 @@ White space is optional around relational operators, regex equality operators, e
 | `()`                 | Priority expression      | Yes                  | `/a==(/b==200)`<br>`/a in ({200})`                             | `/status in({200})`                   |
 | `in`, `not in`       | Set operators            | Yes                  | `/a in {200}`<br>`/a not in {400}`                             | `/a in{200, 202}`<br>`/a not in{400}` |
 | `<`, `<=`, `>`, `>=` | Relational operators     | No                   | `/status < 300`<br>`/status>=300`                              |                                       |
+| `+`                  | String concatenation operator   | No                   | `/status_code + /message + "suffix"`
+| `+`, `-`             | Arithmetic addition and subtraction operators | No      | `/status_code + length(/message) - 2`
+| `*`, `/`             | Multiplication and division operators | No              | `/status_code * length(/message) / 3`
 | `=~`, `!~`           | Regex equality operators | No                   | `/msg =~ "^\w*$"`<br>`/msg=~"^\w*$"`                           |                                       |
 | `==`, `!=`           | Equality operators       | No                   | `/status == 200`<br>`/status_code==200`                        |                                       |
 | `and`, `or`, `not`   | Conditional operators    | Yes                  | `/a<300 and /b>200`                                            | `/b<300and/b>200`                     |