feat: Allow aliases to include default prompt options

README.md

@@ -223,6 +223,7 @@ See also [the llm tag](https://simonwillison.net/tags/llm/) on my blog.
 * [Model aliases](https://llm.datasette.io/en/stable/aliases.html)
   * [Listing aliases](https://llm.datasette.io/en/stable/aliases.html#listing-aliases)
   * [Adding a new alias](https://llm.datasette.io/en/stable/aliases.html#adding-a-new-alias)
+  * [Alias with prompt options](https://llm.datasette.io/en/stable/aliases.html#aliases-with-options)
   * [Removing an alias](https://llm.datasette.io/en/stable/aliases.html#removing-an-alias)
   * [Viewing the aliases file](https://llm.datasette.io/en/stable/aliases.html#viewing-the-aliases-file)
 * [Embeddings](https://llm.datasette.io/en/stable/embeddings/index.html)

docs/aliases.md

@@ -100,6 +100,46 @@ The `llm aliases remove <alias>` command will remove the specified alias:
 llm aliases remove mini
 ```
 
+## Aliases with options
+
+You can save default prompt options with an alias. For example, to create an alias `4o-creative` that always uses `gpt-4o` with a high temperature, you can do this:
+
+```bash
+llm aliases set 4o-creative gpt-4o -o temperature 1.5
+```
+
+Then you can use this alias like so:
+
+```bash
+llm -m 4o-creative 'Write a creative story about a robot'
+```
+
+The model will be called with the `temperature` option set to `1.5`.
+
+If you specify options both in the alias and on the command line, the command-line options will take precedence.
+
+For example:
+
+```bash
+llm -m 4o-creative -o temperature 1.0 'Write a creative story about a robot'
+```
+
+This will override the alias temperature setting.
+
+### OpenRouter plugin example
+
+You can also create aliases for plugin models. Here is an example with openrouter provider configurations:
+
+```bash
+llm aliases set maverick-lowlatency openrouter/meta-llama/llama-4-maverick -o provider '{
+  "order": [
+    "Baseten", 
+    "Parasail"
+  ],
+"allow_fallbacks": false
+}'
+```
+
 ## Viewing the aliases file
 
 Aliases are stored in an `aliases.json` file in the LLM configuration directory.

llm/__init__.py

@@ -97,7 +97,12 @@ def get_models_with_aliases() -> List["ModelWithAliases"]:
     extra_model_aliases: Dict[str, list] = {}
     if aliases_path.exists():
         configured_aliases = json.loads(aliases_path.read_text())
-        for alias, model_id in configured_aliases.items():
+        for alias, model_id_or_config in configured_aliases.items():
+            # Handle both old format (string) and new format (dict with model and options)
+            if isinstance(model_id_or_config, dict) and "model" in model_id_or_config:
+                model_id = model_id_or_config["model"]
+            else:
+                model_id = model_id_or_config
             extra_model_aliases.setdefault(model_id, []).append(alias)
 
     def register(model, async_model=None, aliases=None):
@@ -222,7 +227,12 @@ def get_embedding_models_with_aliases() -> List["EmbeddingModelWithAliases"]:
     extra_model_aliases: Dict[str, list] = {}
     if aliases_path.exists():
         configured_aliases = json.loads(aliases_path.read_text())
-        for alias, model_id in configured_aliases.items():
+        for alias, model_id_or_config in configured_aliases.items():
+            # Handle both old format (string) and new format (dict with model and options)
+            if isinstance(model_id_or_config, dict) and "model" in model_id_or_config:
+                model_id = model_id_or_config["model"]
+            else:
+                model_id = model_id_or_config
             extra_model_aliases.setdefault(model_id, []).append(alias)
 
     def register(model, aliases=None):
@@ -430,6 +440,65 @@ def set_alias(alias, model_id_or_alias):
     path.write_text(json.dumps(current, indent=4) + "\n")
 
 
+def set_alias_with_options(alias, model_id_or_alias, options):
+    """
+    Set an alias to point to the specified model with default options.
+    """
+    path = user_dir() / "aliases.json"
+    path.parent.mkdir(parents=True, exist_ok=True)
+    if not path.exists():
+        path.write_text("{}\n")
+    try:
+        current = json.loads(path.read_text())
+    except json.decoder.JSONDecodeError:
+        # We're going to write a valid JSON file in a moment:
+        current = {}
+    # Resolve model_id_or_alias to a model_id
+    try:
+        model = get_model(model_id_or_alias)
+        model_id = model.model_id
+    except UnknownModelError:
+        # Try to resolve it to an embedding model
+        try:
+            model = get_embedding_model(model_id_or_alias)
+            model_id = model.model_id
+        except UnknownModelError:
+            # Set the alias to the exact string they provided instead
+            model_id = model_id_or_alias
+    # Store as a dictionary with model and options
+    current[alias] = {
+        "model": model_id,
+        "options": options
+    }
+    path.write_text(json.dumps(current, indent=4) + "\n")
+
+
+def resolve_alias_options(alias_or_model_id):
+    """
+    Resolve an alias to its model and options, if it exists.
+    Returns None if not an alias, or a dict with 'model' and 'options' keys.
+    """
+    path = user_dir() / "aliases.json"
+    if not path.exists():
+        return None
+    try:
+        current = json.loads(path.read_text())
+    except json.decoder.JSONDecodeError:
+        return None
+
+    if alias_or_model_id not in current:
+        return None
+
+    alias_value = current[alias_or_model_id]
+
+    # Check if it's the new format (dict with model and options)
+    if isinstance(alias_value, dict) and "model" in alias_value:
+        return alias_value
+
+    # Otherwise it's the old format (just a string), not relevant for options
+    return None
+
+
 def remove_alias(alias):
     """
     Remove an alias.

llm/cli.py

@@ -36,6 +36,8 @@
     get_models_with_aliases,
     user_dir,
     set_alias,
+    set_alias_with_options,
+    resolve_alias_options,
     set_default_model,
     set_default_embedding_model,
     remove_alias,
@@ -742,6 +744,16 @@ def read_prompt():
         else:
             model_id = get_default_model()
 
+    # Resolve alias with options if applicable
+    alias_options = resolve_alias_options(model_id)
+    if alias_options:
+        model_id = alias_options["model"]
+        # Merge alias options with command-line options, giving priority to command-line
+        merged_options = alias_options.get("options", {}).copy()
+        if options:
+            merged_options.update(dict(options))
+        options = list(merged_options.items())
+
     # Now resolve the model
     try:
         if async_:
@@ -1070,6 +1082,16 @@ def chat(
         else:
             model_id = get_default_model()
 
+    # Resolve alias with options if applicable
+    alias_options = resolve_alias_options(model_id)
+    if alias_options:
+        model_id = alias_options["model"]
+        # Merge alias options with command-line options, giving priority to command-line
+        merged_options = alias_options.get("options", {}).copy()
+        if options:
+            merged_options.update(dict(options))
+        options = list(merged_options.items())
+
     # Now resolve the model
     try:
         model = get_model(model_id)
@@ -2679,7 +2701,15 @@ def aliases_list(json_):
     multiple=True,
     help="Set alias for model matching these strings",
 )
-def aliases_set(alias, model_id, query):
+@click.option(
+    "options",
+    "-o",
+    "--option",
+    type=(str, str),
+    multiple=True,
+    help="Options to include with the alias",
+)
+def aliases_set(alias, model_id, query, options):
     """
     Set an alias for a model
 
@@ -2710,14 +2740,19 @@ def aliases_set(alias, model_id, query):
                 "No model found matching query: " + ", ".join(query)
             )
         model_id = found.model.model_id
-        set_alias(alias, model_id)
+        if options:
+            set_alias_with_options(alias, model_id, dict(options))
+        else:
+            set_alias(alias, model_id)
         click.echo(
             f"Alias '{alias}' set to model '{model_id}'",
             err=True,
         )
     else:
-        set_alias(alias, model_id)
-
+        if options:
+            set_alias_with_options(alias, model_id, dict(options))
+        else:
+            set_alias(alias, model_id)
 
 @aliases.command(name="remove")
 @click.argument("alias")