diff --git a/pkg-py/src/querychat/__init__.py b/pkg-py/src/querychat/__init__.py
index 985d24f5..660a202f 100644
--- a/pkg-py/src/querychat/__init__.py
+++ b/pkg-py/src/querychat/__init__.py
@@ -1,3 +1,5 @@
-from querychat.querychat import init, mod_server as server, sidebar, system_prompt, mod_ui as ui
+from querychat.querychat import init, sidebar, system_prompt
+from querychat.querychat import mod_server as server
+from querychat.querychat import mod_ui as ui
 
-__all__ = ["init", "server", "sidebar", "ui", "system_prompt"]
+__all__ = ["init", "server", "sidebar", "system_prompt", "ui"]
diff --git a/pkg-py/src/querychat/querychat.py b/pkg-py/src/querychat/querychat.py
index d52fcb7c..c15db100 100644
--- a/pkg-py/src/querychat/querychat.py
+++ b/pkg-py/src/querychat/querychat.py
@@ -9,9 +9,7 @@
 import chatlas
 import chevron
 import narwhals as nw
-import pandas as pd
 import sqlalchemy
-from narwhals.typing import IntoFrame
 from shiny import Inputs, Outputs, Session, module, reactive, ui
 
 if TYPE_CHECKING:
@@ -145,6 +143,7 @@ def system_prompt(
     data_description: Optional[str] = None,
     extra_instructions: Optional[str] = None,
     categorical_threshold: int = 10,
+    prompt_path: Optional[Path] = None,
 ) -> str:
     """
     Create a system prompt for the chat model based on a data source's schema
@@ -162,6 +161,9 @@ def system_prompt(
     categorical_threshold : int, default=10
         Threshold for determining if a column is categorical based on number of
         unique values
+    prompt_path
+        Optional `Path` to a custom prompt file. If not provided, the default
+        querychat template will be used.
 
     Returns
     -------
@@ -170,7 +172,11 @@ def system_prompt(
 
     """
     # Read the prompt file
-    prompt_path = Path(__file__).parent / "prompt" / "prompt.md"
+    if prompt_path is None:
+        # Default to the prompt file in the same directory as this module
+        # This allows for easy customization by placing a different prompt.md file there
+        prompt_path = Path(__file__).parent / "prompt" / "prompt.md"
+
     prompt_text = prompt_path.read_text()
 
     return chevron.render(
@@ -226,11 +232,14 @@ def df_to_html(df: IntoFrame, maxrows: int = 5) -> str:
 def init(
     data_source: IntoFrame | sqlalchemy.Engine,
     table_name: str,
+    /,
+    *,
     greeting: Optional[str] = None,
     data_description: Optional[str] = None,
     extra_instructions: Optional[str] = None,
-    create_chat_callback: Optional[CreateChatCallback] = None,
+    prompt_path: Optional[Path] = None,
     system_prompt_override: Optional[str] = None,
+    create_chat_callback: Optional[CreateChatCallback] = None,
 ) -> QueryChatConfig:
     """
     Initialize querychat with any compliant data source.
@@ -251,10 +260,22 @@ def init(
         Description of the data in plain text or Markdown
     extra_instructions : str, optional
         Additional instructions for the chat model
+    prompt_path : Path, optional
+        Path to a custom prompt file. If not provided, the default querychat
+        template will be used. This should be a Markdown file that contains the
+        system prompt template. The mustache template can use the following
+        variables:
+        - `{{db_engine}}`: The database engine used (e.g., "DuckDB")
+        - `{{schema}}`: The schema of the data source, generated by
+          `data_source.get_schema()`
+        - `{{data_description}}`: The optional data description provided
+        - `{{extra_instructions}}`: Any additional instructions provided
+    system_prompt_override : str, optional
+        A custom system prompt to use instead of the default. If provided,
+        `data_description`, `extra_instructions`, and `prompt_path` will be
+        silently ignored.
     create_chat_callback : CreateChatCallback, optional
         A function that creates a chat object
-    system_prompt_override : str, optional
-        A custom system prompt to use instead of the default
 
     Returns
     -------
@@ -289,6 +310,7 @@ def init(
         data_source_obj,
         data_description,
         extra_instructions,
+        prompt_path=prompt_path,
     )
 
     # Default chat function if none provided
diff --git a/pkg-r/NAMESPACE b/pkg-r/NAMESPACE
index d1e39fd8..077a6ed0 100644
--- a/pkg-r/NAMESPACE
+++ b/pkg-r/NAMESPACE
@@ -1,5 +1,6 @@
 # Generated by roxygen2: do not edit by hand
 
+export(df_to_schema)
 export(querychat_init)
 export(querychat_server)
 export(querychat_sidebar)
diff --git a/pkg-r/NEWS.md b/pkg-r/NEWS.md
new file mode 100644
index 00000000..811fe69b
--- /dev/null
+++ b/pkg-r/NEWS.md
@@ -0,0 +1,5 @@
+# querychat (development version)
+
+* Initial CRAN submission.
+
+* Added `prompt_path` support for `querychat_system_prompt()`. (Thank you, @oacar! #37)
diff --git a/pkg-r/R/prompt.R b/pkg-r/R/prompt.R
index 75ac68b6..10bfc977 100644
--- a/pkg-r/R/prompt.R
+++ b/pkg-r/R/prompt.R
@@ -4,22 +4,32 @@
 #' schema and optional additional context and instructions.
 #'
 #' @param df A data frame to generate schema information from.
-#' @param name A string containing the name of the table in SQL queries.
-#' @param data_description Optional description of the data, in plain text or Markdown format.
-#' @param extra_instructions Optional additional instructions for the chat model, in plain text or Markdown format.
+#' @param table_name A string containing the name of the table in SQL queries.
+#' @param data_description Optional string in plain text or Markdown format, containing
+#'   a description of the data frame or any additional context that might be
+#'   helpful in understanding the data. This will be included in the system
+#'   prompt for the chat model.
+#' @param extra_instructions Optional string in plain text or Markdown format, containing
+#'   any additional instructions for the chat model. These will be appended at
+#'   the end of the system prompt.
 #' @param categorical_threshold The maximum number of unique values for a text column to be considered categorical.
+#' @param prompt_path Optional string containing the path to a custom prompt file. If
+#'   `NULL`, the default prompt file in the package will be used. This file should
+#'   contain a whisker template for the system prompt, with placeholders for `{{schema}}`,
+#'   `{{data_description}}`, and `{{extra_instructions}}`.
 #'
 #' @return A string containing the system prompt for the chat model.
 #'
 #' @export
 querychat_system_prompt <- function(
   df,
-  name,
+  table_name,
   data_description = NULL,
   extra_instructions = NULL,
-  categorical_threshold = 10
+  categorical_threshold = 10,
+  prompt_path = system.file("prompt", "prompt.md", package = "querychat")
 ) {
-  schema <- df_to_schema(df, name, categorical_threshold)
+  schema <- df_to_schema(df, table_name, categorical_threshold)
 
   if (!is.null(data_description)) {
     data_description <- paste(data_description, collapse = "\n")
@@ -29,26 +39,50 @@ querychat_system_prompt <- function(
   }
 
   # Read the prompt file
-  prompt_path <- system.file("prompt", "prompt.md", package = "querychat")
+  if (is.null(prompt_path)) {
+    prompt_path <- system.file("prompt", "prompt.md", package = "querychat")
+  }
+  if (!file.exists(prompt_path)) {
+    stop("Prompt file not found at: ", prompt_path)
+  }
   prompt_content <- readLines(prompt_path, warn = FALSE)
   prompt_text <- paste(prompt_content, collapse = "\n")
 
-  whisker::whisker.render(
-    prompt_text,
-    list(
-      schema = schema,
-      data_description = data_description,
-      extra_instructions = extra_instructions
+  processed_template <-
+    whisker::whisker.render(
+      prompt_text,
+      list(
+        schema = schema,
+        data_description = data_description,
+        extra_instructions = extra_instructions
+      )
     )
-  )
+
+  attr(processed_template, "table_name") <- table_name
+
+  processed_template
 }
 
+#' Generate a schema description from a data frame
+#'
+#' This function generates a schema description for a data frame, including
+#' the column names, their types, and additional information such as ranges for
+#' numeric columns and unique values for text columns.
+#'
+#' @param df A data frame to generate schema information from.
+#' @param table_name A string containing the name of the table in SQL queries.
+#' @param categorical_threshold The maximum number of unique values for a text column to be considered categorical.
+#'
+#' @return A string containing the schema description for the data frame.
+#' The schema includes the table name, column names, their types, and additional
+#' information such as ranges for numeric columns and unique values for text columns.
+#' @export
 df_to_schema <- function(
   df,
-  name = deparse(substitute(df)),
-  categorical_threshold
+  table_name = deparse(substitute(df)),
+  categorical_threshold = 10
 ) {
-  schema <- c(paste("Table:", name), "Columns:")
+  schema <- c(paste("Table:", table_name), "Columns:")
 
   column_info <- lapply(names(df), function(column) {
     # Map R classes to SQL-like types
diff --git a/pkg-r/R/querychat.R b/pkg-r/R/querychat.R
index f97a867c..eca6a0b8 100644
--- a/pkg-r/R/querychat.R
+++ b/pkg-r/R/querychat.R
@@ -4,29 +4,24 @@
 #' Shiny sessions in the R process.
 #'
 #' @param df A data frame.
-#' @param tbl_name A string containing a valid table name for the data frame,
+#' @param table_name A string containing a valid table name for the data frame,
 #'   that will appear in SQL queries. Ensure that it begins with a letter, and
 #'   contains only letters, numbers, and underscores. By default, querychat will
 #'   try to infer a table name using the name of the `df` argument.
 #' @param greeting A string in Markdown format, containing the initial message
 #'   to display to the user upon first loading the chatbot. If not provided, the
 #'   LLM will be invoked at the start of the conversation to generate one.
-#' @param data_description A string in plain text or Markdown format, containing
-#'   a description of the data frame or any additional context that might be
-#'   helpful in understanding the data. This will be included in the system
-#'   prompt for the chat model. If a `system_prompt` argument is provided, the
-#'   `data_description` argument will be ignored.
-#' @param extra_instructions A string in plain text or Markdown format, containing
-#'   any additional instructions for the chat model. These will be appended at
-#'   the end of the system prompt. If a `system_prompt` argument is provided,
-#'   the `extra_instructions` argument will be ignored.
-#' @param create_chat_func A function that takes a system prompt and returns a
-#'   chat object. The default uses `ellmer::chat_openai()`.
+#' @param ... Additional arguments passed to the `querychat_system_prompt()`
+#'   function, such as `categorical_threshold`, and `prompt_path`. If a
+#'   `system_prompt` argument is provided, the `...` arguments will be silently
+#'   ignored.
+#' @inheritParams querychat_system_prompt
 #' @param system_prompt A string containing the system prompt for the chat model.
 #'   The default uses `querychat_system_prompt()` to generate a generic prompt,
 #'   which you can enhance via the `data_description` and `extra_instructions`
 #'   arguments.
-#'
+#' @param create_chat_func A function that takes a system prompt and returns a
+#'   chat object. The default uses `ellmer::chat_openai()`.
 #' @returns An object that can be passed to `querychat_server()` as the
 #'   `querychat_config` argument. By convention, this object should be named
 #'   `querychat_config`.
@@ -34,45 +29,57 @@
 #' @export
 querychat_init <- function(
   df,
-  tbl_name = deparse(substitute(df)),
+  ...,
+  table_name = deparse(substitute(df)),
   greeting = NULL,
   data_description = NULL,
   extra_instructions = NULL,
-  create_chat_func = purrr::partial(ellmer::chat_openai, model = "gpt-4o"),
   system_prompt = querychat_system_prompt(
     df,
-    tbl_name,
+    table_name,
+    # By default, pass through any params supplied to querychat_init()
+    ...,
     data_description = data_description,
     extra_instructions = extra_instructions
-  )
+  ),
+  create_chat_func = purrr::partial(ellmer::chat_openai, model = "gpt-4o")
 ) {
-  is_tbl_name_ok <- is.character(tbl_name) &&
-    length(tbl_name) == 1 &&
-    grepl("^[a-zA-Z][a-zA-Z0-9_]*$", tbl_name, perl = TRUE)
-  if (!is_tbl_name_ok) {
-    if (missing(tbl_name)) {
+  is_table_name_ok <- is.character(table_name) &&
+    length(table_name) == 1 &&
+    grepl("^[a-zA-Z][a-zA-Z0-9_]*$", table_name, perl = TRUE)
+  if (!is_table_name_ok) {
+    if (missing(table_name)) {
       rlang::abort(
-        "Unable to infer table name from `df` argument. Please specify `tbl_name` argument explicitly."
+        "Unable to infer table name from `df` argument. Please specify `table_name` argument explicitly."
       )
     } else {
       rlang::abort(
-        "`tbl_name` argument must be a string containing a valid table name."
+        "`table_name` argument must be a string containing a valid table name."
       )
     }
   }
 
   force(df)
-  force(system_prompt)
+  force(system_prompt) # Have default `...` params evaluated
   force(create_chat_func)
 
   # TODO: Provide nicer looking errors here
   stopifnot(
     "df must be a data frame" = is.data.frame(df),
-    "tbl_name must be a string" = is.character(tbl_name),
+    "table_name must be a string" = is.character(table_name),
     "system_prompt must be a string" = is.character(system_prompt),
     "create_chat_func must be a function" = is.function(create_chat_func)
   )
 
+  if ("table_name" %in% names(attributes(system_prompt))) {
+    # If available, be sure to use the `table_name` argument to `querychat_init()`
+    # matches the one supplied to the system prompt
+    if (table_name != attr(system_prompt, "table_name")) {
+      rlang::abort(
+        "`querychat_init(table_name=)` must match system prompt `table_name` supplied to `querychat_system_prompt()`."
+      )
+    }
+  }
   if (!is.null(greeting)) {
     greeting <- paste(collapse = "\n", greeting)
   } else {
@@ -83,7 +90,7 @@ querychat_init <- function(
   }
 
   conn <- DBI::dbConnect(duckdb::duckdb(), dbdir = ":memory:")
-  duckdb::duckdb_register(conn, tbl_name, df, experimental = FALSE)
+  duckdb::duckdb_register(conn, table_name, df, experimental = FALSE)
   shiny::onStop(function() DBI::dbDisconnect(conn))
 
   structure(
diff --git a/pkg-r/man/df_to_schema.Rd b/pkg-r/man/df_to_schema.Rd
new file mode 100644
index 00000000..d6060c4c
--- /dev/null
+++ b/pkg-r/man/df_to_schema.Rd
@@ -0,0 +1,29 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/prompt.R
+\name{df_to_schema}
+\alias{df_to_schema}
+\title{Generate a schema description from a data frame}
+\usage{
+df_to_schema(
+  df,
+  table_name = deparse(substitute(df)),
+  categorical_threshold = 10
+)
+}
+\arguments{
+\item{df}{A data frame to generate schema information from.}
+
+\item{table_name}{A string containing the name of the table in SQL queries.}
+
+\item{categorical_threshold}{The maximum number of unique values for a text column to be considered categorical.}
+}
+\value{
+A string containing the schema description for the data frame.
+The schema includes the table name, column names, their types, and additional
+information such as ranges for numeric columns and unique values for text columns.
+}
+\description{
+This function generates a schema description for a data frame, including
+the column names, their types, and additional information such as ranges for
+numeric columns and unique values for text columns.
+}
diff --git a/pkg-r/man/querychat_init.Rd b/pkg-r/man/querychat_init.Rd
index 260261ae..5a0b0c84 100644
--- a/pkg-r/man/querychat_init.Rd
+++ b/pkg-r/man/querychat_init.Rd
@@ -6,19 +6,25 @@
 \usage{
 querychat_init(
   df,
-  tbl_name = deparse(substitute(df)),
+  ...,
+  table_name = deparse(substitute(df)),
   greeting = NULL,
   data_description = NULL,
   extra_instructions = NULL,
-  create_chat_func = purrr::partial(ellmer::chat_openai, model = "gpt-4o"),
-  system_prompt = querychat_system_prompt(df, tbl_name, data_description =
-    data_description, extra_instructions = extra_instructions)
+  system_prompt = querychat_system_prompt(df, table_name, ..., data_description =
+    data_description, extra_instructions = extra_instructions),
+  create_chat_func = purrr::partial(ellmer::chat_openai, model = "gpt-4o")
 )
 }
 \arguments{
 \item{df}{A data frame.}
 
-\item{tbl_name}{A string containing a valid table name for the data frame,
+\item{...}{Additional arguments passed to the \code{querychat_system_prompt()}
+function, such as \code{categorical_threshold}, and \code{prompt_path}. If a
+\code{system_prompt} argument is provided, the \code{...} arguments will be silently
+ignored.}
+
+\item{table_name}{A string containing a valid table name for the data frame,
 that will appear in SQL queries. Ensure that it begins with a letter, and
 contains only letters, numbers, and underscores. By default, querychat will
 try to infer a table name using the name of the \code{df} argument.}
@@ -27,24 +33,22 @@ try to infer a table name using the name of the \code{df} argument.}
 to display to the user upon first loading the chatbot. If not provided, the
 LLM will be invoked at the start of the conversation to generate one.}
 
-\item{data_description}{A string in plain text or Markdown format, containing
+\item{data_description}{Optional string in plain text or Markdown format, containing
 a description of the data frame or any additional context that might be
 helpful in understanding the data. This will be included in the system
-prompt for the chat model. If a \code{system_prompt} argument is provided, the
-\code{data_description} argument will be ignored.}
+prompt for the chat model.}
 
-\item{extra_instructions}{A string in plain text or Markdown format, containing
+\item{extra_instructions}{Optional string in plain text or Markdown format, containing
 any additional instructions for the chat model. These will be appended at
-the end of the system prompt. If a \code{system_prompt} argument is provided,
-the \code{extra_instructions} argument will be ignored.}
-
-\item{create_chat_func}{A function that takes a system prompt and returns a
-chat object. The default uses \code{ellmer::chat_openai()}.}
+the end of the system prompt.}
 
 \item{system_prompt}{A string containing the system prompt for the chat model.
 The default uses \code{querychat_system_prompt()} to generate a generic prompt,
 which you can enhance via the \code{data_description} and \code{extra_instructions}
 arguments.}
+
+\item{create_chat_func}{A function that takes a system prompt and returns a
+chat object. The default uses \code{ellmer::chat_openai()}.}
 }
 \value{
 An object that can be passed to \code{querychat_server()} as the
diff --git a/pkg-r/man/querychat_system_prompt.Rd b/pkg-r/man/querychat_system_prompt.Rd
index 31dae21f..a62b0ac3 100644
--- a/pkg-r/man/querychat_system_prompt.Rd
+++ b/pkg-r/man/querychat_system_prompt.Rd
@@ -6,22 +6,33 @@
 \usage{
 querychat_system_prompt(
   df,
-  name,
+  table_name,
   data_description = NULL,
   extra_instructions = NULL,
-  categorical_threshold = 10
+  categorical_threshold = 10,
+  prompt_path = system.file("prompt", "prompt.md", package = "querychat")
 )
 }
 \arguments{
 \item{df}{A data frame to generate schema information from.}
 
-\item{name}{A string containing the name of the table in SQL queries.}
+\item{table_name}{A string containing the name of the table in SQL queries.}
 
-\item{data_description}{Optional description of the data, in plain text or Markdown format.}
+\item{data_description}{Optional string in plain text or Markdown format, containing
+a description of the data frame or any additional context that might be
+helpful in understanding the data. This will be included in the system
+prompt for the chat model.}
 
-\item{extra_instructions}{Optional additional instructions for the chat model, in plain text or Markdown format.}
+\item{extra_instructions}{Optional string in plain text or Markdown format, containing
+any additional instructions for the chat model. These will be appended at
+the end of the system prompt.}
 
 \item{categorical_threshold}{The maximum number of unique values for a text column to be considered categorical.}
+
+\item{prompt_path}{Optional string containing the path to a custom prompt file. If
+\code{NULL}, the default prompt file in the package will be used. This file should
+contain a whisker template for the system prompt, with placeholders for \code{{{schema}}},
+\code{{{data_description}}}, and \code{{{extra_instructions}}}.}
 }
 \value{
 A string containing the system prompt for the chat model.
diff --git a/pyproject.toml b/pyproject.toml
index daec9962..c5a1787e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -77,7 +77,7 @@ exclude = [
     "node_modules",
     "site-packages",
     "venv",
-    "app-*.py",             # ignore example apps for now
+    "examples",             # ignore example apps for now
 ]
 
 line-length = 88
@@ -110,6 +110,7 @@ extend-ignore = [
     "D104", # Missing docstring in public package
     "D107", # Missing docstring in __init__
     "D205", # 1 blank line required between summary line and description
+    "UP045", # Use `X | NULL` for type annotations, not `Optional[X]`
 ]
 extend-select = [
     # "C90", # C90; mccabe: https://docs.astral.sh/ruff/rules/complex-structure/