Claude Code engine, image viewer, colour tags, checks per turn and more

- Claude Code as an engine: chats on a "claude-code/<alias>" model run through
  the claude CLI (stream-json); tool approvals go through our permission
  system. Sign in from the web UI (URL + pasted code), CLI version and update
  from Settings; the Docker image contains the CLI.
- Small models (8k context) for side tasks: input is cut to the model's
  context window; one-line chat status, "What does this do?" on approvals,
  "Plan as automation" (job draft from a chat).
- Mobile: top bar no longer widens the page, image viewer (zoom, swipe, mark
  up, use in message), jump to previous own message, message menu, time under
  every message.
- Approvals: push actions (allow/reject), "always allow in this project"
  (never for dangerous commands) with revoke.
- Per turn: changed files with diffs and rollback; project check command with
  a green/red badge and "let the agent fix it".
- Colour tags for chats in the colours of the active theme.
- Project defaults for new chats, project page (timeline), offline queue.

Tested in a throwaway container with a mock model (8k small model): 26 API
checks passed (permissions, diffs, checks, defaults, job draft, side-task
budget, Claude Code status/login URL, unsigned-in chat).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

server/src/api.rs

@@ -89,6 +89,12 @@ pub fn router(app: AppState) -> Router {
         .route("/sessions/{id}/abort", post(abort))
         .route("/sessions/{id}/compact", post(compact))
         .route("/sessions/{id}/rewind", post(rewind))
+        .route("/sessions/{id}/job-draft", post(job_draft))
+        .route("/projects/overview", get(project_overview))
+        .route("/sessions/{id}/project-defaults", get(get_project_defaults).put(put_project_defaults).delete(delete_project_defaults))
+        .route("/sessions/{id}/check", get(get_check).put(put_check))
+        .route("/sessions/{id}/checks", get(list_checks))
+        .route("/sessions/{id}/check/run", post(run_check))
         .route("/sessions/{id}/changes", get(changed_files))
         .route("/sessions/{id}/shells", get(list_shells))
         .route("/sessions/{id}/shells/{shell}/kill", post(kill_shell))
@@ -98,6 +104,13 @@ pub fn router(app: AppState) -> Router {
         .route("/sessions/{id}/queue/flush", post(flush_queue))
         .route("/sessions/{id}/queue/{item}", delete(delete_queue_item))
         .route("/permissions/{id}", post(reply_permission))
+        .route("/permissions/{id}/explain", post(explain_permission))
+        .route("/claude/status", get(claude_status))
+        .route("/claude/login", post(claude_login_start).delete(claude_login_cancel))
+        .route("/claude/login/code", post(claude_login_code))
+        .route("/claude/logout", post(claude_logout))
+        .route("/claude/update", post(claude_update))
+        .route("/sessions/{id}/approvals", get(project_approvals).delete(delete_project_approval))
         .route("/questions/{id}", post(answer_question))
         .route("/pending", get(pending))
         .route("/mcp", get(mcp_status))
@@ -595,13 +608,17 @@ fn validate_cwd(app: &App, user: &User, cwd: Option<String>) -> Result<PathBuf,
 async fn create_session(Extension(user): Extension<User>, State(app): State<AppState>, Json(body): Json<CreateSession>) -> ApiResult {
     let cwd = validate_cwd(&app, &user, body.cwd)?;
     let cfg = app.config();
+    // What the project's chats start with (⋯ menu "use as project default").
+    let defaults = app.store.project_defaults(&cwd.display().to_string()).ok().flatten().unwrap_or(Value::Null);
+    let dstr = |k: &str| defaults[k].as_str().filter(|v| !v.is_empty()).map(String::from);
     let model = body
         .model
         .filter(|m| !m.is_empty())
+        .or_else(|| dstr("model").filter(|m| app.registry().resolve(m).is_ok()))
         .or_else(|| Some(cfg.server.default_model.clone()).filter(|m| !m.is_empty()))
         .or_else(|| app.registry().first_model())
         .ok_or_else(|| ApiError(StatusCode::BAD_REQUEST, "no model configured – ask an admin to add a provider".into()))?;
-    let mode = body.permission_mode.unwrap_or_else(|| "auto".into());
+    let mode = body.permission_mode.or_else(|| dstr("permission_mode")).unwrap_or_else(|| "auto".into());
     if !crate::permission::MODES.contains(&mode.as_str()) {
         return Err(ApiError(StatusCode::BAD_REQUEST, "invalid permission mode".into()));
     }
@@ -624,10 +641,12 @@ async fn create_session(Extension(user): Extension<User>, State(app): State<AppS
         worktree: None,
         pinned: false,
         archived: false,
-        folder: None,
-        instructions: String::new(),
+        folder: dstr("folder"),
+        instructions: dstr("instructions").unwrap_or_default(),
         // New chats keep their approvals and questions out of Telegram (⋯ menu turns it on).
         telegram_quiet: true,
+        summary: String::new(),
+        color: dstr("color").filter(|c| codecraft_core::types::SESSION_COLORS.contains(&c.as_str())),
     };
     let s = app.save_session(s)?;
     Ok(Json(json!(s)))
@@ -921,6 +940,8 @@ struct UpdateSession {
     instructions: Option<String>,
     /// Approvals and questions of this chat are not sent to Telegram.
     telegram_quiet: Option<bool>,
+    /// Colour tag ("" removes it).
+    color: Option<String>,
 }
 
 async fn update_session(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>, Json(body): Json<UpdateSession>) -> ApiResult {
@@ -933,6 +954,9 @@ async fn update_session(Extension(user): Extension<User>, State(app): State<AppS
     if let Some(m) = &body.model {
         app.registry().resolve(m)?;
     }
+    if body.color.as_deref().is_some_and(|c| !c.is_empty() && !codecraft_core::types::SESSION_COLORS.contains(&c)) {
+        return Err(ApiError(StatusCode::BAD_REQUEST, "invalid colour".into()));
+    }
     if body.permission_mode.as_deref().is_some_and(|p| !crate::permission::MODES.contains(&p)) {
         return Err(ApiError(StatusCode::BAD_REQUEST, "invalid permission mode".into()));
     }
@@ -972,6 +996,9 @@ async fn update_session(Extension(user): Extension<User>, State(app): State<AppS
         if let Some(q) = body.telegram_quiet {
             s.telegram_quiet = q;
         }
+        if let Some(c) = body.color {
+            s.color = (!c.is_empty()).then_some(c);
+        }
     })?;
     Ok(Json(json!(s)))
 }
@@ -1231,13 +1258,47 @@ async fn kill_shell(Extension(user): Extension<User>, State(app): State<AppState
 #[derive(Deserialize)]
 struct ChangesQuery {
     since_message: String,
+    /// Include a unified diff per file.
+    #[serde(default)]
+    diff: bool,
+    /// Only changes before this message (one turn instead of everything since).
+    until_message: Option<String>,
 }
 
 /// Files the agent changed since a message (for the rewind dialog).
 async fn changed_files(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>, Query(q): Query<ChangesQuery>) -> ApiResult {
     readable(&app, &user, &id)?;
     let since = app.store.message_created_at(&id, &q.since_message)?.unwrap_or(i64::MAX);
-    let files: Vec<Value> = app.store.checkpoints_since(&id, since)?.into_iter().map(|(p, c)| json!({"path": p, "created": c.is_none()})).collect();
+    let until = match &q.until_message {
+        Some(m) => app.store.message_created_at(&id, m)?.unwrap_or(i64::MAX),
+        None => i64::MAX,
+    };
+    let files: Vec<Value> = app
+        .store
+        .checkpoints_between(&id, since, until)?
+        .into_iter()
+        .map(|(p, c)| {
+            let mut v = json!({"path": p, "created": c.is_none()});
+            if q.diff {
+                // Checkpoint (state before the agent's first change) against the file now.
+                let old = c.map(|b| String::from_utf8_lossy(&b).into_owned()).unwrap_or_default();
+                let new = std::fs::read_to_string(&p);
+                v["deleted"] = json!(new.is_err());
+                let new = new.unwrap_or_default();
+                let mut diff = similar::TextDiff::from_lines(&old, &new).unified_diff().context_radius(3).header(&p, &p).to_string();
+                if diff.len() > 60_000 {
+                    let mut end = 60_000;
+                    while !diff.is_char_boundary(end) {
+                        end -= 1;
+                    }
+                    diff.truncate(end);
+                    v["truncated"] = json!(true);
+                }
+                v["diff"] = json!(diff);
+            }
+            v
+        })
+        .collect();
     Ok(Json(json!(files)))
 }
 
@@ -1291,6 +1352,201 @@ async fn reply_permission(Extension(user): Extension<User>, State(app): State<Ap
     Ok(Json(json!({"ok": true})))
 }
 
+/// Instructions for an automation drafted from this chat (small model); the client creates the job.
+async fn job_draft(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>) -> ApiResult {
+    let s = writable(&app, &user, &id)?;
+    let (name, prompt) = runner::draft_job(&app, &s).await.map_err(|e| ApiError(StatusCode::BAD_GATEWAY, format!("{e:#}")))?;
+    Ok(Json(json!({"name": name, "prompt": prompt, "cwd": s.cwd, "agent": s.agent})))
+}
+
+// --- Claude Code: sign-in from the web UI ---------------------------------------------------
+
+#[derive(Deserialize, Default)]
+struct ClaudeStatusQuery {
+    #[serde(default)]
+    refresh: bool,
+}
+
+async fn claude_status(Extension(user): Extension<User>, State(app): State<AppState>, Query(q): Query<ClaudeStatusQuery>) -> Json<Value> {
+    if q.refresh {
+        crate::claude_code::refresh_latest().await;
+    }
+    Json(crate::claude_code::status(&app, &user.id).await)
+}
+
+#[derive(Deserialize, Default)]
+struct ClaudeLoginBody {
+    /// Anthropic Console (API billing) instead of the Claude subscription.
+    #[serde(default)]
+    console: bool,
+}
+
+async fn claude_login_start(Extension(user): Extension<User>, State(app): State<AppState>, body: Option<Json<ClaudeLoginBody>>) -> ApiResult {
+    let console = body.map(|b| b.0.console).unwrap_or(false);
+    let url = crate::claude_code::login_start(&app, &user.id, console).await.map_err(|e| ApiError(StatusCode::BAD_GATEWAY, format!("{e:#}")))?;
+    app.audit(Some(&user), "claude.login_start", "", "");
+    Ok(Json(json!({"url": url})))
+}
+
+#[derive(Deserialize)]
+struct ClaudeCodeBody {
+    code: String,
+}
+
+async fn claude_login_code(Extension(user): Extension<User>, State(app): State<AppState>, Json(b): Json<ClaudeCodeBody>) -> ApiResult {
+    crate::claude_code::login_code(&user.id, &b.code).await.map_err(|e| ApiError(StatusCode::BAD_REQUEST, format!("{e:#}")))?;
+    app.audit(Some(&user), "claude.login", "", "");
+    // New models may have appeared (the CLI is signed in now): clients reload them.
+    Ok(Json(crate::claude_code::status(&app, &user.id).await))
+}
+
+async fn claude_login_cancel(Extension(user): Extension<User>) -> Json<Value> {
+    crate::claude_code::login_cancel(&user.id);
+    Json(json!({"ok": true}))
+}
+
+/// Install the latest Claude Code CLI on the server (admins: it is shared by all accounts).
+async fn claude_update(Extension(user): Extension<User>, State(app): State<AppState>) -> ApiResult {
+    require_admin(&user)?;
+    let output = crate::claude_code::update().await.map_err(|e| ApiError(StatusCode::BAD_GATEWAY, format!("{e:#}")))?;
+    app.audit(Some(&user), "claude.update", "", "");
+    let mut v = crate::claude_code::status(&app, &user.id).await;
+    v["output"] = json!(output);
+    Ok(Json(v))
+}
+
+async fn claude_logout(Extension(user): Extension<User>, State(app): State<AppState>) -> ApiResult {
+    crate::claude_code::logout(&app, &user.id).await.map_err(|e| ApiError(StatusCode::BAD_GATEWAY, format!("{e:#}")))?;
+    app.audit(Some(&user), "claude.logout", "", "");
+    Ok(Json(crate::claude_code::status(&app, &user.id).await))
+}
+
+// --- project page ---------------------------------------------------------------------------------
+
+#[derive(Deserialize)]
+struct OverviewQuery {
+    cwd: String,
+}
+
+/// Chats of a project folder with what they did (files, checks, cost) plus the folder's settings.
+async fn project_overview(Extension(user): Extension<User>, State(app): State<AppState>, Query(q): Query<OverviewQuery>) -> ApiResult {
+    let filter = if user.is_admin() { None } else { Some(user.id.as_str()) };
+    let sessions: Vec<Session> = app.store.list_sessions(filter)?.into_iter().filter(|s| s.cwd == q.cwd).collect();
+    let ids: Vec<String> = sessions.iter().map(|s| s.id.clone()).collect();
+    let check = app.store.project_check(&q.cwd)?;
+    Ok(Json(json!({
+        "sessions": app.store.project_overview(&ids)?,
+        "check": check.map(|c| json!({"command": c.0, "enabled": c.1})),
+        "defaults": app.store.project_defaults(&q.cwd)?,
+        "currency": app.config().server.currency,
+    })))
+}
+
+// --- defaults of new chats per project ---------------------------------------------------------
+
+async fn get_project_defaults(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>) -> ApiResult {
+    let s = readable(&app, &user, &id)?;
+    Ok(Json(app.store.project_defaults(&s.cwd)?.unwrap_or(Value::Null)))
+}
+
+/// Remember this chat's colour, model, mode, instructions and folder for new chats in the project folder.
+async fn put_project_defaults(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>) -> ApiResult {
+    let s = writable(&app, &user, &id)?;
+    let data = json!({
+        "model": s.model, "agent": s.agent, "permission_mode": s.permission_mode,
+        "color": s.color, "instructions": s.instructions, "folder": s.folder,
+    });
+    app.store.set_project_defaults(&s.cwd, Some(&data))?;
+    Ok(Json(data))
+}
+
+async fn delete_project_defaults(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>) -> ApiResult {
+    let s = writable(&app, &user, &id)?;
+    app.store.set_project_defaults(&s.cwd, None)?;
+    Ok(Json(json!({"ok": true})))
+}
+
+// --- check command per project ------------------------------------------------------------------
+
+async fn get_check(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>) -> ApiResult {
+    let s = readable(&app, &user, &id)?;
+    let c = app.store.project_check(&s.cwd)?;
+    Ok(Json(json!({"command": c.as_ref().map(|c| c.0.clone()).unwrap_or_default(), "enabled": c.map(|c| c.1).unwrap_or(false)})))
+}
+
+#[derive(Deserialize)]
+struct CheckBody {
+    command: String,
+    #[serde(default = "yes")]
+    enabled: bool,
+}
+
+fn yes() -> bool {
+    true
+}
+
+async fn put_check(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>, Json(b): Json<CheckBody>) -> ApiResult {
+    let s = writable(&app, &user, &id)?;
+    if b.command.len() > 2000 {
+        return Err(ApiError(StatusCode::BAD_REQUEST, "command too long".into()));
+    }
+    app.store.set_project_check(&s.cwd, &b.command, b.enabled)?;
+    app.audit(Some(&user), "project.check", &s.cwd, &b.command);
+    Ok(Json(json!({"ok": true})))
+}
+
+async fn list_checks(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>) -> ApiResult {
+    readable(&app, &user, &id)?;
+    Ok(Json(json!(app.store.turn_checks(&id)?)))
+}
+
+/// Run the check now for the latest answer.
+async fn run_check(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>) -> ApiResult {
+    let s = writable(&app, &user, &id)?;
+    let last = app.store.messages(&id)?.into_iter().rev().find(|m| m.role == crate::types::Role::Assistant).ok_or_else(|| ApiError(StatusCode::BAD_REQUEST, "no answer yet".into()))?;
+    let app2 = app.clone();
+    tokio::spawn(async move {
+        let _ = crate::checks::run(&app2, &s, &last.id).await;
+    });
+    Ok(Json(json!({"ok": true})))
+}
+
+#[derive(Deserialize, Default)]
+struct ExplainBody {
+    lang: Option<String>,
+}
+
+/// Plain-words explanation of a pending approval (small model).
+async fn explain_permission(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>, body: Option<Json<ExplainBody>>) -> ApiResult {
+    check_pending(&app, &user, &id)?;
+    let ev = app.pending_events().into_iter().find(|e| matches!(e, Event::PermissionRequest { id: i, .. } if *i == id)).ok_or_else(|| not_found("request"))?;
+    let Event::PermissionRequest { session_id, tool, title, input, diff, .. } = ev else { return Err(not_found("request")) };
+    let session = app.session(&session_id)?;
+    let lang = body.and_then(|b| b.0.lang).unwrap_or_default();
+    let text = crate::runner::explain_tool_call(&app, &session, &tool, &title, &input, diff.as_deref(), &lang)
+        .await
+        .map_err(|e| ApiError(StatusCode::BAD_GATEWAY, format!("{e:#}")))?;
+    Ok(Json(json!({"text": text})))
+}
+
+/// What is allowed "for this project" (remembered across chats).
+async fn project_approvals(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>) -> ApiResult {
+    let s = readable(&app, &user, &id)?;
+    Ok(Json(json!(app.store.project_approvals(&s.cwd)?)))
+}
+
+#[derive(Deserialize)]
+struct ApprovalKey {
+    key: String,
+}
+
+async fn delete_project_approval(Extension(user): Extension<User>, State(app): State<AppState>, Path(id): Path<String>, Json(body): Json<ApprovalKey>) -> ApiResult {
+    let s = writable(&app, &user, &id)?;
+    app.store.delete_project_approval(&s.cwd, &body.key)?;
+    app.audit(Some(&user), "permission.project_revoked", body.key, "");
+    Ok(Json(json!({"ok": true})))
+}
+
 #[derive(Deserialize)]
 struct QuestionBody {
     /// question text → answer (string or array of strings); null = dismissed
@@ -1887,6 +2143,8 @@ async fn job_assistant(Extension(user): Extension<User>, State(app): State<AppSt
         folder: None,
         instructions,
         telegram_quiet: true,
+        summary: String::new(),
+        color: None,
     };
     let s = app.save_session(s)?;
     st.assistant_session = Some(s.id.clone());