Add per-chat settings UI in web app for additional system prompt and tool checkboxes

docs/api/rest.md

@@ -42,6 +42,23 @@ Chat upload limits:
 - `hermes-agent` is included only when `HERMES_AGENT_API_KEY` is configured. Set it to Hermes `API_SERVER_KEY`, or any non-empty value if that local server does not require auth. `HERMES_AGENT_API_BASE_URL` defaults to `http://127.0.0.1:8642/v1`; set `HERMES_AGENT_MODEL` only when you need an additional fallback/override model id.
 - The backend loads provider model lists at startup and refreshes them about once every 24 hours. If a later provider refresh fails, the response keeps the last loaded model list for that provider and sets `error` to the latest failure message.
 
+## Chat Tools
+
+### `GET /v1/chat-tools`
+- Response:
+```json
+{
+  "tools": [
+    { "name": "web_search", "description": "..." },
+    { "name": "fetch_url", "description": "..." }
+  ]
+}
+```
+
+Behavior notes:
+- Lists Sybil-managed chat tools that can be enabled for `openai` and `xai` chat completions.
+- Optional tools such as `codex_exec` and `shell_exec` appear only when enabled by server environment configuration.
+
 ## Active Runs
 
 ### `GET /v1/active-runs`
@@ -77,7 +94,9 @@ Behavior notes:
       "initiatedProvider": "openai",
       "initiatedModel": "gpt-4.1-mini",
       "lastUsedProvider": "openai",
-      "lastUsedModel": "gpt-4.1-mini"
+      "lastUsedModel": "gpt-4.1-mini",
+      "additionalSystemPrompt": null,
+      "enabledTools": ["web_search", "fetch_url"]
     },
     {
       "type": "search",
@@ -111,6 +130,8 @@ Behavior notes:
   "title": "optional title",
   "provider": "optional openai|anthropic|xai|hermes-agent",
   "model": "optional model id",
+  "additionalSystemPrompt": "optional stored system prompt",
+  "enabledTools": ["web_search", "fetch_url"],
   "messages": [
     {
       "role": "system|user|assistant|tool",
@@ -126,13 +147,17 @@ Behavior notes:
 Behavior notes:
 - `provider` and `model` must be supplied together when present.
 - When `provider`/`model` are supplied, the new chat initializes `initiatedProvider`/`initiatedModel` and `lastUsedProvider`/`lastUsedModel`.
+- `additionalSystemPrompt` is trimmed and stored on the chat; blank values are stored as `null`.
+- `enabledTools` stores the enabled Sybil-managed tool names for future chat completions. Unknown tool names are ignored; omitted values default to all currently available tools.
 - Optional `messages` are inserted as the initial transcript. Attachment metadata uses the same schema and limits as chat completion messages.
 
 ### `PATCH /v1/chats/:chatId`
-- Body: `{ "title": string }`
+- Body: any subset of `{ "title": string, "additionalSystemPrompt": string|null, "enabledTools": string[] }`
 - Response: `{ "chat": ChatSummary }`
 - Blank titles are rejected. The server trims surrounding whitespace before storing the title.
-- Renaming updates the returned chat's `updatedAt`.
+- `additionalSystemPrompt: null` clears the stored prompt. Blank string values are also stored as `null`.
+- `enabledTools: []` disables Sybil-managed tools for this chat. Omitted settings are left unchanged.
+- Updating chat fields changes the returned chat's `updatedAt`.
 - Not found: `404 { "message": "chat not found" }`
 
 ### `PATCH /v1/chats/:chatId/star`
@@ -237,6 +262,8 @@ Notes:
       ]
     }
   ],
+  "additionalSystemPrompt": "optional one-off system prompt",
+  "enabledTools": ["web_search", "fetch_url"],
   "temperature": 0.2,
   "maxTokens": 256
 }
@@ -256,6 +283,8 @@ Notes:
 Behavior notes:
 - If `chatId` is present, server validates chat existence.
 - For `chatId` calls, server stores only *new* non-assistant messages from provided history to avoid duplicates.
+- `additionalSystemPrompt`, when present directly or loaded from stored chat settings, is prepended to the provider request as a `system` message and is not inserted into the persisted chat transcript by this endpoint.
+- `enabledTools` limits Sybil-managed tools for this request. When omitted for a saved chat, the stored chat setting is used; otherwise all available tools are enabled by default. An empty array disables Sybil-managed tools.
 - Server persists final assistant output and call metadata (`LlmCall`) in DB.
 - Server updates chat-level model metadata on each call: `lastUsedProvider`/`lastUsedModel`; first successful/failed call also initializes `initiatedProvider`/`initiatedModel` if unset.
 - Attachments are optional and currently apply to `user` messages. Persisted chat history stores them under `message.metadata.attachments`.
@@ -390,7 +419,9 @@ Behavior notes:
   "initiatedProvider": "openai|anthropic|xai|hermes-agent|null",
   "initiatedModel": "string|null",
   "lastUsedProvider": "openai|anthropic|xai|hermes-agent|null",
-  "lastUsedModel": "string|null"
+  "lastUsedModel": "string|null",
+  "additionalSystemPrompt": null,
+  "enabledTools": ["web_search", "fetch_url"]
 }
 ```
 
@@ -441,6 +472,8 @@ Behavior notes:
   "initiatedModel": "string|null",
   "lastUsedProvider": "openai|anthropic|xai|hermes-agent|null",
   "lastUsedModel": "string|null",
+  "additionalSystemPrompt": null,
+  "enabledTools": ["web_search", "fetch_url"],
   "messages": [Message]
 }
 ```