assistant: Make it easier to define custom models (#15442)

This PR makes it easier to specify custom models for the Google, OpenAI,
and Anthropic provider:

Before (google):

```json
{
  "language_models": {
    "google": {
      "available_models": [
        {
          "custom": {
            "name": "my-custom-google-model",
            "max_tokens": 12345
          }
        }
      ]
    }
  }
}
```

After (google):

```json
{
  "language_models": {
    "google": {
      "available_models": [
        {
          "name": "my-custom-google-model",
          "max_tokens": 12345
        }
      ]
    }
  }
}
```

Before (anthropic):

```json
{
  "language_models": {
    "anthropic": {
      "available_models": [
        {
          "custom": {
            "name": "my-custom-anthropic-model",
            "max_tokens": 12345
          }
        }
      ]
    }
  }
}
```

After (anthropic):

```json
{
  "language_models": {
    "anthropic": {
      "version": "1",
      "available_models": [
        {
          "name": "my-custom-anthropic-model",
          "max_tokens": 12345
        }
      ]
    }
  }
}

```

The settings will be auto-upgraded so the old versions will continue to
work (except for Google since that one has not been released).

/cc @as-cii 

Release Notes:

- N/A

---------

Co-authored-by: Thorsten <thorsten@zed.dev>

crates/language_model/src/provider/anthropic.rs

@@ -12,6 +12,8 @@ use gpui::{
     WhiteSpace,
 };
 use http_client::HttpClient;
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
 use settings::{Settings, SettingsStore};
 use std::{sync::Arc, time::Duration};
 use strum::IntoEnumIterator;
@@ -26,7 +28,14 @@ const PROVIDER_NAME: &str = "Anthropic";
 pub struct AnthropicSettings {
     pub api_url: String,
     pub low_speed_timeout: Option<Duration>,
-    pub available_models: Vec<anthropic::Model>,
+    pub available_models: Vec<AvailableModel>,
+    pub needs_setting_migration: bool,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, JsonSchema)]
+pub struct AvailableModel {
+    pub name: String,
+    pub max_tokens: usize,
 }
 
 pub struct AnthropicLanguageModelProvider {
@@ -84,7 +93,13 @@ impl LanguageModelProvider for AnthropicLanguageModelProvider {
             .available_models
             .iter()
         {
-            models.insert(model.id().to_string(), model.clone());
+            models.insert(
+                model.name.clone(),
+                anthropic::Model::Custom {
+                    name: model.name.clone(),
+                    max_tokens: model.max_tokens,
+                },
+            );
         }
 
         models

crates/language_model/src/provider/google.rs

@@ -8,6 +8,8 @@ use gpui::{
     WhiteSpace,
 };
 use http_client::HttpClient;
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
 use settings::{Settings, SettingsStore};
 use std::{future, sync::Arc, time::Duration};
 use strum::IntoEnumIterator;
@@ -28,7 +30,13 @@ const PROVIDER_NAME: &str = "Google AI";
 pub struct GoogleSettings {
     pub api_url: String,
     pub low_speed_timeout: Option<Duration>,
-    pub available_models: Vec<google_ai::Model>,
+    pub available_models: Vec<AvailableModel>,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, JsonSchema)]
+pub struct AvailableModel {
+    name: String,
+    max_tokens: usize,
 }
 
 pub struct GoogleLanguageModelProvider {
@@ -86,7 +94,13 @@ impl LanguageModelProvider for GoogleLanguageModelProvider {
             .google
             .available_models
         {
-            models.insert(model.id().to_string(), model.clone());
+            models.insert(
+                model.name.clone(),
+                google_ai::Model::Custom {
+                    name: model.name.clone(),
+                    max_tokens: model.max_tokens,
+                },
+            );
         }
 
         models

crates/language_model/src/provider/open_ai.rs

@@ -8,6 +8,8 @@ use gpui::{
 };
 use http_client::HttpClient;
 use open_ai::stream_completion;
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
 use settings::{Settings, SettingsStore};
 use std::{future, sync::Arc, time::Duration};
 use strum::IntoEnumIterator;
@@ -28,7 +30,14 @@ const PROVIDER_NAME: &str = "OpenAI";
 pub struct OpenAiSettings {
     pub api_url: String,
     pub low_speed_timeout: Option<Duration>,
-    pub available_models: Vec<open_ai::Model>,
+    pub available_models: Vec<AvailableModel>,
+    pub needs_setting_migration: bool,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, JsonSchema)]
+pub struct AvailableModel {
+    pub name: String,
+    pub max_tokens: usize,
 }
 
 pub struct OpenAiLanguageModelProvider {
@@ -86,7 +95,13 @@ impl LanguageModelProvider for OpenAiLanguageModelProvider {
             .openai
             .available_models
         {
-            models.insert(model.id().to_string(), model.clone());
+            models.insert(
+                model.name.clone(),
+                open_ai::Model::Custom {
+                    name: model.name.clone(),
+                    max_tokens: model.max_tokens,
+                },
+            );
         }
 
         models