test(picloud): close two app_members test gaps

- `membership_makes_app_appear_in_members_app_list` previously seeded
  the membership via the repo helper; switch to the public POST
  endpoint so the test actually exercises the full HTTP round-trip
  the dashboard depends on.
- Add `add_member_with_missing_user_id_is_rejected` to pin the
  Axum-JsonRejection 4xx contract on malformed POST bodies.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/manager-core/src/app_members_api.rs

@@ -0,0 +1,331 @@
+//! `/api/v1/admin/apps/{id_or_slug}/members/*` — CRUD over the
+//! `app_members` table (blueprint §11.6).
+//!
+//! Every endpoint is gated on `Capability::AppAdmin(app_id)` after
+//! resolving the app from `id_or_slug`. Editors and viewers receive
+//! 403 from list and never see the dashboard's Members tab.
+//!
+//! POST is **non-idempotent on purpose**: a duplicate `(app_id,
+//! user_id)` returns 409 rather than upsert-200, so the UI can show
+//! "already a member — promote / demote them instead" cleanly. Role
+//! changes go through PATCH.
+//!
+//! No last-app-admin guard: owners always implicitly satisfy
+//! `Capability::AppAdmin(_)` (authz::role_grants), so removing the
+//! final explicit `app_admin` membership cannot orphan an app.
+
+use std::sync::Arc;
+
+use axum::extract::{Path, State};
+use axum::http::StatusCode;
+use axum::response::{IntoResponse, Json, Response};
+use axum::routing::{get, patch};
+use axum::{Extension, Router};
+use chrono::{DateTime, Utc};
+use picloud_shared::{AdminUserId, AppRole, InstanceRole, Principal};
+use serde::{Deserialize, Serialize};
+use serde_json::json;
+use uuid::Uuid;
+
+use crate::admin_user_repo::{AdminUserRepository, AdminUserRepositoryError, AdminUserRow};
+use crate::app_members_repo::{
+    AppMembersRepository, AppMembersRepositoryError, AppMembershipDetail, AppMembershipRow,
+};
+use crate::app_repo::AppRepository;
+use crate::authz::{require, AuthzDenied, AuthzRepo, Capability};
+use crate::repo::ScriptRepositoryError;
+
+#[derive(Clone)]
+pub struct AppMembersState {
+    pub apps: Arc<dyn AppRepository>,
+    pub users: Arc<dyn AdminUserRepository>,
+    pub members: Arc<dyn AppMembersRepository>,
+    pub authz: Arc<dyn AuthzRepo>,
+}
+
+pub fn app_members_router(state: AppMembersState) -> Router {
+    Router::new()
+        .route(
+            "/apps/{id_or_slug}/members",
+            get(list_members).post(grant_member),
+        )
+        .route(
+            "/apps/{id_or_slug}/members/{user_id}",
+            patch(patch_member).delete(remove_member),
+        )
+        .with_state(state)
+}
+
+// ----------------------------------------------------------------------------
+// DTOs
+// ----------------------------------------------------------------------------
+
+#[derive(Debug, Serialize)]
+pub struct AppMemberDto {
+    pub user_id: AdminUserId,
+    pub username: String,
+    pub email: Option<String>,
+    pub instance_role: InstanceRole,
+    pub is_active: bool,
+    pub role: AppRole,
+    pub created_at: DateTime<Utc>,
+}
+
+impl From<AppMembershipDetail> for AppMemberDto {
+    fn from(d: AppMembershipDetail) -> Self {
+        Self {
+            user_id: d.user_id,
+            username: d.username,
+            email: d.email,
+            instance_role: d.instance_role,
+            is_active: d.is_active,
+            role: d.role,
+            created_at: d.created_at,
+        }
+    }
+}
+
+/// Compose a DTO from an `AdminUserRow` (fetched for validation) and
+/// the `AppMembershipRow` returned by `upsert`. Saves a re-fetch on
+/// POST/PATCH at the cost of trusting the two inputs reference the
+/// same user_id — caller's responsibility.
+fn compose_dto(user: AdminUserRow, membership: AppMembershipRow) -> AppMemberDto {
+    AppMemberDto {
+        user_id: user.id,
+        username: user.username,
+        email: user.email,
+        instance_role: user.instance_role,
+        is_active: user.is_active,
+        role: membership.role,
+        created_at: membership.created_at,
+    }
+}
+
+#[derive(Debug, Deserialize)]
+pub struct GrantMemberRequest {
+    pub user_id: AdminUserId,
+    pub role: AppRole,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct PatchMemberRequest {
+    pub role: AppRole,
+}
+
+// ----------------------------------------------------------------------------
+// Handlers
+// ----------------------------------------------------------------------------
+
+async fn list_members(
+    State(s): State<AppMembersState>,
+    Extension(principal): Extension<Principal>,
+    Path(id_or_slug): Path<String>,
+) -> Result<Json<Vec<AppMemberDto>>, AppMembersApiError> {
+    let app = resolve_app(&*s.apps, &id_or_slug).await?;
+    require(s.authz.as_ref(), &principal, Capability::AppAdmin(app.id)).await?;
+    let rows = s.members.list_for_app_enriched(app.id).await?;
+    Ok(Json(rows.into_iter().map(Into::into).collect()))
+}
+
+async fn grant_member(
+    State(s): State<AppMembersState>,
+    Extension(principal): Extension<Principal>,
+    Path(id_or_slug): Path<String>,
+    Json(input): Json<GrantMemberRequest>,
+) -> Result<(StatusCode, Json<AppMemberDto>), AppMembersApiError> {
+    let app = resolve_app(&*s.apps, &id_or_slug).await?;
+    require(s.authz.as_ref(), &principal, Capability::AppAdmin(app.id)).await?;
+
+    let user = s
+        .users
+        .get(input.user_id)
+        .await?
+        .ok_or(AppMembersApiError::UserNotFound(input.user_id))?;
+    validate_grant_target(&user)?;
+
+    // Atomic insert — if a row already exists, returns None and we 409.
+    // Avoids the find-then-upsert race where two concurrent POSTs would
+    // both pass the existence check and the second `upsert` would
+    // silently rewrite the role.
+    let row = s
+        .members
+        .try_insert(app.id, user.id, input.role)
+        .await?
+        .ok_or_else(|| AppMembersApiError::AlreadyMember {
+            username: user.username.clone(),
+        })?;
+    Ok((StatusCode::CREATED, Json(compose_dto(user, row))))
+}
+
+async fn patch_member(
+    State(s): State<AppMembersState>,
+    Extension(principal): Extension<Principal>,
+    Path((id_or_slug, user_id)): Path<(String, Uuid)>,
+    Json(input): Json<PatchMemberRequest>,
+) -> Result<Json<AppMemberDto>, AppMembersApiError> {
+    let app = resolve_app(&*s.apps, &id_or_slug).await?;
+    require(s.authz.as_ref(), &principal, Capability::AppAdmin(app.id)).await?;
+
+    let user_id = AdminUserId::from(user_id);
+    let user = s
+        .users
+        .get(user_id)
+        .await?
+        .ok_or(AppMembersApiError::UserNotFound(user_id))?;
+
+    // Atomic update — returns None if no row exists, so 404 is decided
+    // by the same statement that does the write. Eliminates the
+    // find-then-upsert race where a concurrent DELETE between the two
+    // calls would let PATCH silently re-create the row.
+    let row = s
+        .members
+        .update_role(app.id, user_id, input.role)
+        .await?
+        .ok_or(AppMembersApiError::MembershipNotFound)?;
+    Ok(Json(compose_dto(user, row)))
+}
+
+async fn remove_member(
+    State(s): State<AppMembersState>,
+    Extension(principal): Extension<Principal>,
+    Path((id_or_slug, user_id)): Path<(String, Uuid)>,
+) -> Result<StatusCode, AppMembersApiError> {
+    let app = resolve_app(&*s.apps, &id_or_slug).await?;
+    require(s.authz.as_ref(), &principal, Capability::AppAdmin(app.id)).await?;
+    s.members.remove(app.id, AdminUserId::from(user_id)).await?;
+    Ok(StatusCode::NO_CONTENT)
+}
+
+// ----------------------------------------------------------------------------
+// Validation + helpers
+// ----------------------------------------------------------------------------
+
+fn validate_grant_target(user: &AdminUserRow) -> Result<(), AppMembersApiError> {
+    if !user.is_active {
+        return Err(AppMembersApiError::TargetInactive {
+            username: user.username.clone(),
+        });
+    }
+    if user.instance_role != InstanceRole::Member {
+        return Err(AppMembersApiError::TargetNotMember {
+            username: user.username.clone(),
+            instance_role: user.instance_role,
+        });
+    }
+    Ok(())
+}
+
+async fn resolve_app(
+    apps: &dyn AppRepository,
+    ident: &str,
+) -> Result<picloud_shared::App, AppMembersApiError> {
+    crate::app_repo::resolve_app(apps, ident)
+        .await?
+        .map(|l| l.app)
+        .ok_or_else(|| AppMembersApiError::AppNotFound(ident.to_string()))
+}
+
+// ----------------------------------------------------------------------------
+// Errors
+// ----------------------------------------------------------------------------
+
+#[derive(Debug, thiserror::Error)]
+pub enum AppMembersApiError {
+    #[error("app not found: {0}")]
+    AppNotFound(String),
+
+    #[error("user not found: {0}")]
+    UserNotFound(AdminUserId),
+
+    #[error("no membership exists for this user on this app")]
+    MembershipNotFound,
+
+    #[error("{username} is already a member of this app — use PATCH to change their role")]
+    AlreadyMember { username: String },
+
+    #[error("{username} is deactivated and cannot be added as a member")]
+    TargetInactive { username: String },
+
+    #[error(
+        "{username} has instance_role {instance_role:?} and already has implicit access \
+         on every app — no explicit membership needed"
+    )]
+    TargetNotMember {
+        username: String,
+        instance_role: InstanceRole,
+    },
+
+    #[error("forbidden")]
+    Forbidden,
+
+    #[error("authorization repo error: {0}")]
+    AuthzRepo(String),
+
+    #[error("repository error: {0}")]
+    Members(#[from] AppMembersRepositoryError),
+
+    #[error("user repository error: {0}")]
+    Users(#[from] AdminUserRepositoryError),
+
+    #[error("repository error: {0}")]
+    Apps(#[from] ScriptRepositoryError),
+}
+
+impl From<AuthzDenied> for AppMembersApiError {
+    fn from(d: AuthzDenied) -> Self {
+        match d {
+            AuthzDenied::Denied => Self::Forbidden,
+            AuthzDenied::Repo(e) => Self::AuthzRepo(e.to_string()),
+        }
+    }
+}
+
+impl IntoResponse for AppMembersApiError {
+    fn into_response(self) -> Response {
+        let (status, body) = match &self {
+            Self::AppNotFound(_)
+            | Self::UserNotFound(_)
+            | Self::MembershipNotFound
+            | Self::Apps(ScriptRepositoryError::NotFound(_)) => {
+                (StatusCode::NOT_FOUND, json!({ "error": self.to_string() }))
+            }
+            Self::AlreadyMember { .. } | Self::Apps(ScriptRepositoryError::Conflict(_)) => {
+                (StatusCode::CONFLICT, json!({ "error": self.to_string() }))
+            }
+            Self::TargetInactive { .. } | Self::TargetNotMember { .. } => (
+                StatusCode::UNPROCESSABLE_ENTITY,
+                json!({ "error": self.to_string() }),
+            ),
+            Self::Forbidden => (StatusCode::FORBIDDEN, json!({ "error": self.to_string() })),
+            Self::AuthzRepo(e) => {
+                tracing::error!(error = %e, "app members authz repo error");
+                (
+                    StatusCode::INTERNAL_SERVER_ERROR,
+                    json!({ "error": "internal error" }),
+                )
+            }
+            Self::Members(e) => {
+                tracing::error!(error = %e, "app members repo error");
+                (
+                    StatusCode::INTERNAL_SERVER_ERROR,
+                    json!({ "error": "internal error" }),
+                )
+            }
+            Self::Users(e) => {
+                tracing::error!(error = %e, "admin users repo error");
+                (
+                    StatusCode::INTERNAL_SERVER_ERROR,
+                    json!({ "error": "internal error" }),
+                )
+            }
+            Self::Apps(ScriptRepositoryError::Db(e)) => {
+                tracing::error!(error = %e, "apps repo error in app_members");
+                (
+                    StatusCode::INTERNAL_SERVER_ERROR,
+                    json!({ "error": "internal error" }),
+                )
+            }
+        };
+        (status, Json(body)).into_response()
+    }
+}

crates/manager-core/src/app_members_repo.rs

@@ -8,7 +8,7 @@
 
 use async_trait::async_trait;
 use chrono::{DateTime, Utc};
-use picloud_shared::{AdminUserId, AppId, AppRole};
+use picloud_shared::{AdminUserId, AppId, AppRole, InstanceRole};
 use sqlx::PgPool;
 
 use crate::authz::{AuthzError, AuthzRepo};
@@ -36,6 +36,20 @@ pub struct AppMembershipRow {
     pub created_at: DateTime<Utc>,
 }
 
+/// `app_members` row joined with `admin_users` so the dashboard's
+/// Members tab can render usernames / emails / status without an N+1
+/// fetch per row. Drives `GET /apps/{id}/members`.
+#[derive(Debug, Clone)]
+pub struct AppMembershipDetail {
+    pub user_id: AdminUserId,
+    pub username: String,
+    pub email: Option<String>,
+    pub instance_role: InstanceRole,
+    pub is_active: bool,
+    pub role: AppRole,
+    pub created_at: DateTime<Utc>,
+}
+
 #[async_trait]
 pub trait AppMembersRepository: Send + Sync {
     /// Single (user, app) lookup. Returns `None` for non-members and
@@ -55,6 +69,27 @@ pub trait AppMembersRepository: Send + Sync {
         role: AppRole,
     ) -> Result<AppMembershipRow, AppMembersRepositoryError>;
 
+    /// Atomic insert. Returns `Some(row)` on success, `None` if a
+    /// membership already exists. Lets the HTTP handler return 409
+    /// without a separate `find` round-trip (no TOCTOU between check
+    /// and insert).
+    async fn try_insert(
+        &self,
+        app_id: AppId,
+        user_id: AdminUserId,
+        role: AppRole,
+    ) -> Result<Option<AppMembershipRow>, AppMembersRepositoryError>;
+
+    /// Atomic role update. Returns `Some(row)` on success, `None` if no
+    /// membership row exists. Lets PATCH return 404 without a separate
+    /// `find` round-trip (no TOCTOU between check and update).
+    async fn update_role(
+        &self,
+        app_id: AppId,
+        user_id: AdminUserId,
+        role: AppRole,
+    ) -> Result<Option<AppMembershipRow>, AppMembersRepositoryError>;
+
     /// Remove a membership. No-op (Ok) when the row doesn't exist —
     /// the user wasn't a member, which is the desired post-condition.
     async fn remove(
@@ -78,6 +113,14 @@ pub trait AppMembersRepository: Send + Sync {
         &self,
         app_id: AppId,
     ) -> Result<Vec<AppMembershipRow>, AppMembersRepositoryError>;
+
+    /// Like `list_for_app` but joined with `admin_users` so the
+    /// dashboard can render member rows in one round-trip. Ordered by
+    /// username for a stable list.
+    async fn list_for_app_enriched(
+        &self,
+        app_id: AppId,
+    ) -> Result<Vec<AppMembershipDetail>, AppMembersRepositoryError>;
 }
 
 pub struct PostgresAppMembersRepository {
@@ -143,6 +186,45 @@ impl AppMembersRepository for PostgresAppMembersRepository {
         Ok(())
     }
 
+    async fn try_insert(
+        &self,
+        app_id: AppId,
+        user_id: AdminUserId,
+        role: AppRole,
+    ) -> Result<Option<AppMembershipRow>, AppMembersRepositoryError> {
+        let row = sqlx::query_as::<_, AppMembershipRecord>(
+            "INSERT INTO app_members (app_id, user_id, role) \
+             VALUES ($1, $2, $3) \
+             ON CONFLICT (app_id, user_id) DO NOTHING \
+             RETURNING app_id, user_id, role, created_at",
+        )
+        .bind(app_id.into_inner())
+        .bind(user_id.into_inner())
+        .bind(role.as_str())
+        .fetch_optional(&self.pool)
+        .await?;
+        row.map(TryInto::try_into).transpose()
+    }
+
+    async fn update_role(
+        &self,
+        app_id: AppId,
+        user_id: AdminUserId,
+        role: AppRole,
+    ) -> Result<Option<AppMembershipRow>, AppMembersRepositoryError> {
+        let row = sqlx::query_as::<_, AppMembershipRecord>(
+            "UPDATE app_members SET role = $1 \
+             WHERE app_id = $2 AND user_id = $3 \
+             RETURNING app_id, user_id, role, created_at",
+        )
+        .bind(role.as_str())
+        .bind(app_id.into_inner())
+        .bind(user_id.into_inner())
+        .fetch_optional(&self.pool)
+        .await?;
+        row.map(TryInto::try_into).transpose()
+    }
+
     async fn list_for_user(
         &self,
         user_id: AdminUserId,
@@ -172,6 +254,24 @@ impl AppMembersRepository for PostgresAppMembersRepository {
         .await?;
         rows.into_iter().map(TryInto::try_into).collect()
     }
+
+    async fn list_for_app_enriched(
+        &self,
+        app_id: AppId,
+    ) -> Result<Vec<AppMembershipDetail>, AppMembersRepositoryError> {
+        let rows = sqlx::query_as::<_, AppMembershipDetailRecord>(
+            "SELECT au.id, au.username, au.email, au.instance_role, au.is_active, \
+                    am.role, am.created_at \
+             FROM app_members am \
+             JOIN admin_users au ON au.id = am.user_id \
+             WHERE am.app_id = $1 \
+             ORDER BY au.username",
+        )
+        .bind(app_id.into_inner())
+        .fetch_all(&self.pool)
+        .await?;
+        rows.into_iter().map(TryInto::try_into).collect()
+    }
 }
 
 /// Forwarding impl so the Postgres repo satisfies `AuthzRepo` directly
@@ -210,3 +310,31 @@ impl TryFrom<AppMembershipRecord> for AppMembershipRow {
         })
     }
 }
+
+#[derive(sqlx::FromRow)]
+struct AppMembershipDetailRecord {
+    id: uuid::Uuid,
+    username: String,
+    email: Option<String>,
+    instance_role: String,
+    is_active: bool,
+    role: String,
+    created_at: DateTime<Utc>,
+}
+
+impl TryFrom<AppMembershipDetailRecord> for AppMembershipDetail {
+    type Error = AppMembersRepositoryError;
+    fn try_from(r: AppMembershipDetailRecord) -> Result<Self, Self::Error> {
+        Ok(Self {
+            user_id: r.id.into(),
+            username: r.username,
+            email: r.email,
+            instance_role: InstanceRole::from_db_str(&r.instance_role)
+                .ok_or(AppMembersRepositoryError::InvalidRole(r.instance_role))?,
+            is_active: r.is_active,
+            role: AppRole::from_db_str(&r.role)
+                .ok_or(AppMembersRepositoryError::InvalidRole(r.role))?,
+            created_at: r.created_at,
+        })
+    }
+}

crates/manager-core/src/app_repo.rs

@@ -8,6 +8,7 @@
 use async_trait::async_trait;
 use picloud_shared::{AdminUserId, App, AppId};
 use sqlx::PgPool;
+use uuid::Uuid;
 
 use crate::repo::ScriptRepositoryError;
 
@@ -20,6 +21,32 @@ pub struct AppLookup {
     pub redirected: bool,
 }
 
+/// Resolve a free-form path param (UUID *or* slug *or* historical slug)
+/// to an `AppLookup`. UUID lookups never set `redirected`; slug lookups
+/// fall through to `app_slug_history` and set `redirected: true` when
+/// they hit it.
+///
+/// Returns `Ok(None)` when nothing matches — callers map that to their
+/// own not-found error variant.
+///
+/// # Errors
+/// Propagates any underlying repository error.
+pub async fn resolve_app(
+    apps: &dyn AppRepository,
+    ident: &str,
+) -> Result<Option<AppLookup>, ScriptRepositoryError> {
+    if let Ok(uuid) = ident.parse::<Uuid>() {
+        return Ok(apps
+            .get_by_id(AppId::from(uuid))
+            .await?
+            .map(|app| AppLookup {
+                app,
+                redirected: false,
+            }));
+    }
+    apps.get_by_slug_or_history(ident).await
+}
+
 #[async_trait]
 pub trait AppRepository: Send + Sync {
     /// Every app on the instance. For owner/admin callers — `member`

crates/manager-core/src/apps_api.rs

@@ -17,14 +17,14 @@ use axum::response::{IntoResponse, Json, Response};
 use axum::routing::{delete, get, post};
 use axum::{Extension, Router};
 use picloud_orchestrator_core::routing::{pattern, AppDomainTable, CompiledAppDomain};
-use picloud_shared::{App, AppDomain, AppId, InstanceRole, Principal};
+use picloud_shared::{App, AppDomain, AppId, AppRole, InstanceRole, Principal};
 use serde::{Deserialize, Serialize};
 use serde_json::json;
 use uuid::Uuid;
 
 use crate::app_domain_repo::{AppDomainRepository, NewAppDomain};
 use crate::app_repo::AppRepository;
-use crate::authz::{require, AuthzDenied, AuthzRepo, Capability};
+use crate::authz::{require, AuthzDenied, AuthzError, AuthzRepo, Capability};
 use crate::repo::ScriptRepositoryError;
 use crate::route_repo::RouteRepository;
 
@@ -141,6 +141,12 @@ pub struct AppLookupResponse {
     /// at the live slug so dashboards can redirect.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub redirect_to: Option<String>,
+    /// The caller's role on this app, used by the dashboard to decide
+    /// whether to render admin-only surfaces (Members tab, settings).
+    /// `Owner` maps to `app_admin`, `Admin` to `editor` (both implicit
+    /// per blueprint §11.6); `Member` carries its explicit
+    /// `app_members.role`.
+    pub my_role: Option<AppRole>,
 }
 
 // ----------------------------------------------------------------------------
@@ -209,12 +215,31 @@ async fn get_app(
     } else {
         None
     };
+    let my_role = compute_my_role(s.authz.as_ref(), &principal, lookup.app.id).await?;
     Ok(Json(AppLookupResponse {
         app: lookup.app,
         redirect_to,
+        my_role,
     }))
 }
 
+/// Compute the caller's effective `AppRole` on a specific app. Mirrors
+/// the implicit-grant logic in `authz::role_grants` but returns the
+/// role itself (for UI gating) rather than a yes/no decision. `Owner`
+/// is implicit `AppAdmin` everywhere; `Admin` is implicit `Editor`
+/// everywhere; `Member` consults `app_members`.
+async fn compute_my_role(
+    authz: &dyn AuthzRepo,
+    principal: &Principal,
+    app_id: AppId,
+) -> Result<Option<AppRole>, AppsApiError> {
+    match principal.instance_role {
+        InstanceRole::Owner => Ok(Some(AppRole::AppAdmin)),
+        InstanceRole::Admin => Ok(Some(AppRole::Editor)),
+        InstanceRole::Member => Ok(authz.membership(principal.user_id, app_id).await?),
+    }
+}
+
 async fn patch_app(
     State(s): State<AppsState>,
     Extension(principal): Extension<Principal>,
@@ -429,16 +454,7 @@ async fn resolve_app(
     apps: &dyn AppRepository,
     ident: &str,
 ) -> Result<crate::app_repo::AppLookup, AppsApiError> {
-    if let Ok(uuid) = ident.parse::<Uuid>() {
+    crate::app_repo::resolve_app(apps, ident)
-        if let Some(app) = apps.get_by_id(AppId::from(uuid)).await? {
-            return Ok(crate::app_repo::AppLookup {
-                app,
-                redirected: false,
-            });
-        }
-        return Err(AppsApiError::AppNotFound(ident.to_string()));
-    }
-    apps.get_by_slug_or_history(ident)
         .await?
         .ok_or_else(|| AppsApiError::AppNotFound(ident.to_string()))
 }
@@ -546,6 +562,12 @@ impl From<AuthzDenied> for AppsApiError {
     }
 }
 
+impl From<AuthzError> for AppsApiError {
+    fn from(e: AuthzError) -> Self {
+        Self::AuthzRepo(e.to_string())
+    }
+}
+
 impl IntoResponse for AppsApiError {
     fn into_response(self) -> Response {
         let (status, body) = match &self {

crates/manager-core/src/lib.rs

@@ -12,6 +12,7 @@ pub mod api_key_repo;
 pub mod api_keys_api;
 pub mod app_bootstrap;
 pub mod app_domain_repo;
+pub mod app_members_api;
 pub mod app_members_repo;
 pub mod app_repo;
 pub mod apps_api;
@@ -45,10 +46,12 @@ pub use api_key_repo::{
 pub use api_keys_api::{api_keys_router, ApiKeysState};
 pub use app_bootstrap::{seed_hello_world_if_fresh, HelloWorldOutcome};
 pub use app_domain_repo::{AppDomainRepository, NewAppDomain, PostgresAppDomainRepository};
+pub use app_members_api::{app_members_router, AppMembersApiError, AppMembersState};
 pub use app_members_repo::{
-    AppMembersRepository, AppMembersRepositoryError, AppMembershipRow, PostgresAppMembersRepository,
+    AppMembersRepository, AppMembersRepositoryError, AppMembershipDetail, AppMembershipRow,
+    PostgresAppMembersRepository,
 };
-pub use app_repo::{AppLookup, AppRepository, PostgresAppRepository};
+pub use app_repo::{resolve_app, AppLookup, AppRepository, PostgresAppRepository};
 pub use apps_api::{apps_router, AppsState};
 pub use auth_api::auth_router;
 pub use auth_bootstrap::{

crates/picloud/src/lib.rs

@@ -10,14 +10,15 @@ use axum::middleware::from_fn_with_state;
 use axum::{routing::get, Json, Router};
 use picloud_executor_core::{Engine, Limits};
 use picloud_manager_core::{
-    admin_router, admins_router, api_keys_router, apps_api, apps_router, auth_router,
+    admin_router, admins_router, api_keys_router, app_members_router, apps_api, apps_router,
-    compile_routes, migrations, require_authenticated, route_admin_router, AdminSessionRepository,
+    auth_router, compile_routes, migrations, require_authenticated, route_admin_router,
-    AdminState, AdminUserRepository, AdminsState, ApiKeyRepository, ApiKeysState,
+    AdminSessionRepository, AdminState, AdminUserRepository, AdminsState, ApiKeyRepository,
-    AppDomainRepository, AppRepository, AppsState, AuthState, AuthzRepo,
+    ApiKeysState, AppDomainRepository, AppMembersRepository, AppMembersState, AppRepository,
-    PostgresAdminSessionRepository, PostgresAdminUserRepository, PostgresApiKeyRepository,
+    AppsState, AuthState, AuthzRepo, PostgresAdminSessionRepository, PostgresAdminUserRepository,
-    PostgresAppDomainRepository, PostgresAppMembersRepository, PostgresAppRepository,
+    PostgresApiKeyRepository, PostgresAppDomainRepository, PostgresAppMembersRepository,
-    PostgresExecutionLogRepository, PostgresExecutionLogSink, PostgresRouteRepository,
+    PostgresAppRepository, PostgresExecutionLogRepository, PostgresExecutionLogSink,
-    PostgresScriptRepository, RepoResolver, RouteAdminState, RouteRepository, SandboxCeiling,
+    PostgresRouteRepository, PostgresScriptRepository, RepoResolver, RouteAdminState,
+    RouteRepository, SandboxCeiling,
 };
 use picloud_orchestrator_core::routing::{AppDomainTable, RouteTable};
 use picloud_orchestrator_core::{
@@ -79,6 +80,7 @@ fn read_session_ttl() -> Duration {
 /// the `require_admin` middleware. The data plane
 /// (`/api/v1/execute/{id}`, the user-route fallthrough, `/healthz`,
 /// `/version`) stays open — it's the public ingress for user scripts.
+#[allow(clippy::too_many_lines)]
 pub async fn build_app(pool: PgPool, auth: AuthDeps) -> anyhow::Result<Router> {
     let engine = Arc::new(Engine::new(Limits::default()));
 
@@ -89,9 +91,13 @@ pub async fn build_app(pool: PgPool, auth: AuthDeps) -> anyhow::Result<Router> {
     let apps_repo: Arc<dyn AppRepository> = Arc::new(PostgresAppRepository::new(pool.clone()));
     let domains_repo: Arc<dyn AppDomainRepository> =
         Arc::new(PostgresAppDomainRepository::new(pool.clone()));
-    // Authz: app_members repo doubles as the AuthzRepo impl for the
+    // The Postgres app_members repo implements both `AppMembersRepository`
-    // per-handler capability checks introduced in Phase 3.5.
+    // (CRUD over the table) and `AuthzRepo` (single-row membership lookup
-    let authz: Arc<dyn AuthzRepo> = Arc::new(PostgresAppMembersRepository::new(pool));
+    // for capability checks). Construct it once and clone the Arc into
+    // both trait views — same allocation, two vtables.
+    let members_concrete = Arc::new(PostgresAppMembersRepository::new(pool));
+    let members: Arc<dyn AppMembersRepository> = members_concrete.clone();
+    let authz: Arc<dyn AuthzRepo> = members_concrete;
 
     // Compile the routes table once at startup; admin writes refresh it.
     let route_table = Arc::new(RouteTable::new());
@@ -159,9 +165,15 @@ pub async fn build_app(pool: PgPool, auth: AuthDeps) -> anyhow::Result<Router> {
         ttl: auth.ttl,
     };
     let admins_state = AdminsState {
-        users: auth.users,
+        users: auth.users.clone(),
         sessions: auth.sessions,
         keys: auth.keys.clone(),
+        authz: authz.clone(),
+    };
+    let app_members_state = AppMembersState {
+        apps: apps_state.apps.clone(),
+        users: auth.users,
+        members,
         authz,
     };
     let api_keys_state = ApiKeysState { keys: auth.keys };
@@ -177,6 +189,7 @@ pub async fn build_app(pool: PgPool, auth: AuthDeps) -> anyhow::Result<Router> {
         .merge(route_admin_router(route_admin))
         .merge(admins_router(admins_state))
         .merge(apps_router(apps_state))
+        .merge(app_members_router(app_members_state))
         .merge(api_keys_router(api_keys_state))
         .layer(from_fn_with_state(
             auth_state.clone(),

crates/picloud/tests/authz.rs

@@ -160,6 +160,72 @@ async fn mint_key(server: &TestServer, cred_token: &str, body: Value) -> axum_te
         .await
 }
 
+// --- app members helpers ----------------------------------------------------
+
+async fn list_members(
+    server: &TestServer,
+    token: &str,
+    app_ident: &str,
+) -> axum_test::TestResponse {
+    server
+        .get(&format!("/api/v1/admin/apps/{app_ident}/members"))
+        .add_header("authorization", format!("Bearer {token}"))
+        .await
+}
+
+async fn add_member(
+    server: &TestServer,
+    token: &str,
+    app_ident: &str,
+    user_id: AdminUserId,
+    role: AppRole,
+) -> axum_test::TestResponse {
+    server
+        .post(&format!("/api/v1/admin/apps/{app_ident}/members"))
+        .add_header("authorization", format!("Bearer {token}"))
+        .json(&json!({ "user_id": user_id, "role": role.as_str() }))
+        .await
+}
+
+async fn patch_member_role(
+    server: &TestServer,
+    token: &str,
+    app_ident: &str,
+    user_id: AdminUserId,
+    role: AppRole,
+) -> axum_test::TestResponse {
+    server
+        .patch(&format!("/api/v1/admin/apps/{app_ident}/members/{user_id}",))
+        .add_header("authorization", format!("Bearer {token}"))
+        .json(&json!({ "role": role.as_str() }))
+        .await
+}
+
+async fn remove_member(
+    server: &TestServer,
+    token: &str,
+    app_ident: &str,
+    user_id: AdminUserId,
+) -> axum_test::TestResponse {
+    server
+        .delete(&format!("/api/v1/admin/apps/{app_ident}/members/{user_id}",))
+        .add_header("authorization", format!("Bearer {token}"))
+        .await
+}
+
+/// Direct-DB inactive-user seed — the create-then-deactivate dance
+/// through the API is more ceremony than the test needs.
+async fn seed_inactive_user(pool: &PgPool, username: &str, password: &str) -> AdminUserId {
+    let repo = PostgresAdminUserRepository::new(pool.clone());
+    let hash = hash_password(password).expect("hash");
+    let row = repo
+        .create(username, &hash, InstanceRole::Member, None)
+        .await
+        .expect("seed user");
+    repo.set_active(row.id, false).await.expect("deactivate");
+    row.id
+}
+
 // ----------------------------------------------------------------------------
 // 1. Bootstrap admin → owner
 // ----------------------------------------------------------------------------
@@ -645,3 +711,389 @@ async fn list_active_owners_drives_the_multi_owner_warning(pool: PgPool) {
         .expect("count");
     assert_eq!(remaining, 1, "one other owner should remain (owner2)");
 }
+
+// ----------------------------------------------------------------------------
+// 12. `my_role` on GET /apps/{id_or_slug} reflects the caller's effective role
+// ----------------------------------------------------------------------------
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn my_role_field_matches_caller_role(pool: PgPool) {
+    let s = boot(pool).await;
+
+    // Owner → implicit app_admin everywhere.
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let r = s
+        .server
+        .get("/api/v1/admin/apps/default")
+        .add_header("authorization", format!("Bearer {owner_token}"))
+        .await;
+    r.assert_status_ok();
+    assert_eq!(
+        r.json::<Value>()["my_role"].as_str(),
+        Some("app_admin"),
+        "owner reports app_admin"
+    );
+
+    // Admin → implicit editor everywhere.
+    seed_user(&s.pool, "alice", "alice-pw", InstanceRole::Admin).await;
+    let admin_token = login_token(&s.server, "alice", "alice-pw").await;
+    let r = s
+        .server
+        .get("/api/v1/admin/apps/default")
+        .add_header("authorization", format!("Bearer {admin_token}"))
+        .await;
+    r.assert_status_ok();
+    assert_eq!(
+        r.json::<Value>()["my_role"].as_str(),
+        Some("editor"),
+        "admin reports editor"
+    );
+
+    // Member with explicit `viewer` membership → viewer.
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    grant_membership(&s.pool, bob, s.default_app, AppRole::Viewer).await;
+    let bob_token = login_token(&s.server, "bob", "bob-pw").await;
+    let r = s
+        .server
+        .get("/api/v1/admin/apps/default")
+        .add_header("authorization", format!("Bearer {bob_token}"))
+        .await;
+    r.assert_status_ok();
+    assert_eq!(
+        r.json::<Value>()["my_role"].as_str(),
+        Some("viewer"),
+        "member with viewer row reports viewer"
+    );
+}
+
+// ----------------------------------------------------------------------------
+// 13. App members CRUD — `/api/v1/admin/apps/{id_or_slug}/members[/{user_id}]`
+// ----------------------------------------------------------------------------
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn list_members_includes_seeded_member(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    grant_membership(&s.pool, bob, s.default_app, AppRole::Viewer).await;
+
+    let r = list_members(&s.server, &owner_token, "default").await;
+    r.assert_status_ok();
+    let rows = r.json::<Vec<Value>>();
+    let bob_row = rows
+        .iter()
+        .find(|v| v["username"] == "bob")
+        .expect("bob in list");
+    assert_eq!(bob_row["role"], "viewer");
+    assert_eq!(bob_row["instance_role"], "member");
+    assert_eq!(bob_row["is_active"], true);
+    assert!(bob_row["created_at"].is_string(), "carries created_at");
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn list_members_requires_app_admin(pool: PgPool) {
+    let s = boot(pool).await;
+
+    // Bob has explicit editor on default app — enough to read scripts,
+    // not enough to see the member list.
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    grant_membership(&s.pool, bob, s.default_app, AppRole::Editor).await;
+    let bob_token = login_token(&s.server, "bob", "bob-pw").await;
+
+    let r = list_members(&s.server, &bob_token, "default").await;
+    r.assert_status(axum::http::StatusCode::FORBIDDEN);
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn add_member_creates_row(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+
+    let r = add_member(&s.server, &owner_token, "default", bob, AppRole::Viewer).await;
+    r.assert_status(axum::http::StatusCode::CREATED);
+    let body = r.json::<Value>();
+    assert_eq!(body["username"], "bob");
+    assert_eq!(body["role"], "viewer");
+    assert_eq!(body["instance_role"], "member");
+
+    // Visible on subsequent list.
+    let rows = list_members(&s.server, &owner_token, "default")
+        .await
+        .json::<Vec<Value>>();
+    assert!(rows.iter().any(|v| v["username"] == "bob"));
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn add_member_duplicate_returns_409(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    grant_membership(&s.pool, bob, s.default_app, AppRole::Viewer).await;
+
+    let r = add_member(&s.server, &owner_token, "default", bob, AppRole::Editor).await;
+    r.assert_status(axum::http::StatusCode::CONFLICT);
+    let err = r.json::<Value>()["error"]
+        .as_str()
+        .expect("error message")
+        .to_string();
+    assert!(err.contains("already a member"), "got: {err}");
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn add_member_inactive_user_returns_422(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let bob = seed_inactive_user(&s.pool, "bob", "bob-pw").await;
+
+    let r = add_member(&s.server, &owner_token, "default", bob, AppRole::Viewer).await;
+    r.assert_status(axum::http::StatusCode::UNPROCESSABLE_ENTITY);
+    let err = r.json::<Value>()["error"]
+        .as_str()
+        .expect("error message")
+        .to_string();
+    assert!(err.contains("deactivated"), "got: {err}");
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn add_member_admin_target_returns_422(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let alice = seed_user(&s.pool, "alice", "alice-pw", InstanceRole::Admin).await;
+
+    let r = add_member(&s.server, &owner_token, "default", alice, AppRole::Viewer).await;
+    r.assert_status(axum::http::StatusCode::UNPROCESSABLE_ENTITY);
+    let err = r.json::<Value>()["error"]
+        .as_str()
+        .expect("error message")
+        .to_string();
+    assert!(err.contains("implicit access"), "got: {err}");
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn add_member_owner_target_returns_422(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let other_owner = seed_user(&s.pool, "owner2", "ow2-pw", InstanceRole::Owner).await;
+
+    let r = add_member(
+        &s.server,
+        &owner_token,
+        "default",
+        other_owner,
+        AppRole::Viewer,
+    )
+    .await;
+    r.assert_status(axum::http::StatusCode::UNPROCESSABLE_ENTITY);
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn patch_member_promotes_role(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    grant_membership(&s.pool, bob, s.default_app, AppRole::Viewer).await;
+
+    let r = patch_member_role(&s.server, &owner_token, "default", bob, AppRole::Editor).await;
+    r.assert_status_ok();
+    assert_eq!(r.json::<Value>()["role"], "editor");
+
+    // Editor can now create a script (capability promotion observable
+    // end-to-end, not just via the role string).
+    let bob_token = login_token(&s.server, "bob", "bob-pw").await;
+    create_script_via_api(&s.server, &bob_token, s.default_app, "bob-script").await;
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn patch_member_without_existing_returns_404(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+
+    // No grant yet — PATCH must 404.
+    let r = patch_member_role(&s.server, &owner_token, "default", bob, AppRole::Editor).await;
+    r.assert_status(axum::http::StatusCode::NOT_FOUND);
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn patch_member_same_role_is_idempotent(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    grant_membership(&s.pool, bob, s.default_app, AppRole::Viewer).await;
+
+    let r = patch_member_role(&s.server, &owner_token, "default", bob, AppRole::Viewer).await;
+    r.assert_status_ok();
+    assert_eq!(r.json::<Value>()["role"], "viewer");
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn delete_member_removes_row(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    grant_membership(&s.pool, bob, s.default_app, AppRole::Viewer).await;
+
+    let r = remove_member(&s.server, &owner_token, "default", bob).await;
+    r.assert_status(axum::http::StatusCode::NO_CONTENT);
+
+    let rows = list_members(&s.server, &owner_token, "default")
+        .await
+        .json::<Vec<Value>>();
+    assert!(rows.iter().all(|v| v["username"] != "bob"));
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn delete_member_missing_returns_204(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    // No grant ever happened — delete is idempotent.
+
+    let r = remove_member(&s.server, &owner_token, "default", bob).await;
+    r.assert_status(axum::http::StatusCode::NO_CONTENT);
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn mutating_endpoints_require_app_admin(pool: PgPool) {
+    let s = boot(pool).await;
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    grant_membership(&s.pool, bob, s.default_app, AppRole::Viewer).await;
+    let bob_token = login_token(&s.server, "bob", "bob-pw").await;
+
+    let target = seed_user(&s.pool, "carol", "carol-pw", InstanceRole::Member).await;
+
+    let r = add_member(&s.server, &bob_token, "default", target, AppRole::Viewer).await;
+    r.assert_status(axum::http::StatusCode::FORBIDDEN);
+
+    let r = patch_member_role(&s.server, &bob_token, "default", bob, AppRole::Editor).await;
+    r.assert_status(axum::http::StatusCode::FORBIDDEN);
+
+    let r = remove_member(&s.server, &bob_token, "default", bob).await;
+    r.assert_status(axum::http::StatusCode::FORBIDDEN);
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn members_endpoint_resolves_by_id_or_slug(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+
+    let by_slug = list_members(&s.server, &owner_token, "default").await;
+    by_slug.assert_status_ok();
+    let by_id = list_members(&s.server, &owner_token, &s.default_app.to_string()).await;
+    by_id.assert_status_ok();
+    assert_eq!(
+        by_slug.json::<Value>(),
+        by_id.json::<Value>(),
+        "id and slug return identical bodies",
+    );
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn member_app_admin_can_manage_members(pool: PgPool) {
+    let s = boot(pool).await;
+
+    // Bob is a member with explicit app_admin role on default.
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    grant_membership(&s.pool, bob, s.default_app, AppRole::AppAdmin).await;
+    let bob_token = login_token(&s.server, "bob", "bob-pw").await;
+
+    // Bob can list members.
+    let r = list_members(&s.server, &bob_token, "default").await;
+    r.assert_status_ok();
+
+    // Bob can add carol as viewer.
+    let carol = seed_user(&s.pool, "carol", "carol-pw", InstanceRole::Member).await;
+    let r = add_member(&s.server, &bob_token, "default", carol, AppRole::Viewer).await;
+    r.assert_status(axum::http::StatusCode::CREATED);
+
+    // Bob can promote carol to editor.
+    let r = patch_member_role(&s.server, &bob_token, "default", carol, AppRole::Editor).await;
+    r.assert_status_ok();
+
+    // Bob can remove carol.
+    let r = remove_member(&s.server, &bob_token, "default", carol).await;
+    r.assert_status(axum::http::StatusCode::NO_CONTENT);
+
+    // And bob can even remove himself — owner's implicit AppAdmin
+    // means the app isn't orphaned. This is the load-bearing test for
+    // the no-last-app-admin-guard decision.
+    let r = remove_member(&s.server, &bob_token, "default", bob).await;
+    r.assert_status(axum::http::StatusCode::NO_CONTENT);
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn membership_makes_app_appear_in_members_app_list(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+
+    let bob = seed_user(&s.pool, "bob", "bob-pw", InstanceRole::Member).await;
+    let bob_token = login_token(&s.server, "bob", "bob-pw").await;
+
+    // Before grant: bob sees no apps.
+    let r = s
+        .server
+        .get("/api/v1/admin/apps")
+        .add_header("authorization", format!("Bearer {bob_token}"))
+        .await;
+    r.assert_status_ok();
+    assert!(
+        r.json::<Vec<Value>>().is_empty(),
+        "bob has no memberships → empty apps list"
+    );
+
+    // Grant via the public POST endpoint — exercises the full
+    // round-trip the dashboard goes through, not just the repo seam.
+    let r = add_member(&s.server, &owner_token, "default", bob, AppRole::Viewer).await;
+    r.assert_status(axum::http::StatusCode::CREATED);
+
+    // After grant: bob sees the default app.
+    let r = s
+        .server
+        .get("/api/v1/admin/apps")
+        .add_header("authorization", format!("Bearer {bob_token}"))
+        .await;
+    r.assert_status_ok();
+    let apps = r.json::<Vec<Value>>();
+    assert_eq!(apps.len(), 1);
+    assert_eq!(apps[0]["slug"], "default");
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[sqlx::test(migrations = "../manager-core/migrations")]
+async fn add_member_with_missing_user_id_is_rejected(pool: PgPool) {
+    let s = boot(pool).await;
+    let owner_token = login_token(&s.server, "owner", "owner-pw").await;
+
+    // Body missing `user_id` — Axum's Json extractor produces a 4xx
+    // before our handler runs. Pinning the status to keep the contract
+    // honest if anyone ever swaps the extractor.
+    let r = s
+        .server
+        .post("/api/v1/admin/apps/default/members")
+        .add_header("authorization", format!("Bearer {owner_token}"))
+        .json(&json!({ "role": "viewer" }))
+        .await;
+    let status = r.status_code().as_u16();
+    assert!(
+        (400..500).contains(&status),
+        "malformed body should produce a 4xx, got {status}"
+    );
+}

dashboard/src/lib/RoleChip.svelte

@@ -1,15 +1,24 @@
 <script lang="ts">
 	import type { InstanceRole } from '$lib/auth';
+	import type { AppRole } from '$lib/api';
 
 	interface Props {
-		role: InstanceRole;
+		role?: InstanceRole;
+		appRole?: AppRole;
 		size?: 'sm' | 'md';
 	}
 
-	let { role, size = 'md' }: Props = $props();
+	let { role, appRole, size = 'md' }: Props = $props();
+
+	// Display label: app roles read better with a space ("app admin")
+	// than their wire form ("app_admin").
+	const label = $derived(
+		appRole ? appRole.replace('_', ' ') : (role ?? '')
+	);
+	const cls = $derived(appRole ? `chip-${appRole}` : `chip-${role}`);
 </script>
 
-<span class="chip chip-{role}" class:sm={size === 'sm'}>{role}</span>
+<span class="chip {cls}" class:sm={size === 'sm'}>{label}</span>
 
 <style>
 	.chip {
@@ -42,4 +51,19 @@
 		color: #cbd5e1;
 		border-color: #334155;
 	}
+	.chip-app_admin {
+		background: #4c1d95;
+		color: #c4b5fd;
+		border-color: #6d28d9;
+	}
+	.chip-editor {
+		background: #1e3a8a;
+		color: #93c5fd;
+		border-color: #1d4ed8;
+	}
+	.chip-viewer {
+		background: #1f2937;
+		color: #9ca3af;
+		border-color: #374151;
+	}
 </style>

dashboard/src/lib/api.ts

@@ -44,6 +44,8 @@ export interface App {
 	updated_at: string;
 }
 
+export type AppRole = 'app_admin' | 'editor' | 'viewer';
+
 export type DomainShape = 'exact' | 'wildcard' | 'parameterized';
 
 export interface AppDomain {
@@ -64,6 +66,11 @@ export interface AppLookupResponse {
 	updated_at: string;
 	/// Present only when the requested slug was a retired redirect.
 	redirect_to?: string;
+	/// The caller's role on this app — owners are implicit `app_admin`,
+	/// admins implicit `editor`, members carry their `app_members.role`.
+	/// `null` only when a member somehow reaches the endpoint without
+	/// a membership (the server normally 403s first).
+	my_role: AppRole | null;
 }
 
 export interface SlugCheckResponse {
@@ -289,6 +296,21 @@ export interface PatchAdminInput {
 	email?: string | null;
 }
 
+export interface AppMemberDto {
+	user_id: string;
+	username: string;
+	email: string | null;
+	instance_role: InstanceRole;
+	is_active: boolean;
+	role: AppRole;
+	created_at: string;
+}
+
+export interface GrantAppMemberInput {
+	user_id: string;
+	role: AppRole;
+}
+
 export interface ApiKeyDto {
 	id: string;
 	prefix: string;
@@ -472,6 +494,28 @@ export const api = {
 			)
 	},
 
+	appMembers: {
+		list: (idOrSlug: string) =>
+			adminRequest<AppMemberDto[]>(
+				`/api/v1/admin/apps/${encodeURIComponent(idOrSlug)}/members`
+			),
+		add: (idOrSlug: string, input: GrantAppMemberInput) =>
+			adminRequest<AppMemberDto>(
+				`/api/v1/admin/apps/${encodeURIComponent(idOrSlug)}/members`,
+				{ method: 'POST', body: JSON.stringify(input) }
+			),
+		setRole: (idOrSlug: string, userId: string, role: AppRole) =>
+			adminRequest<AppMemberDto>(
+				`/api/v1/admin/apps/${encodeURIComponent(idOrSlug)}/members/${userId}`,
+				{ method: 'PATCH', body: JSON.stringify({ role }) }
+			),
+		remove: (idOrSlug: string, userId: string) =>
+			adminRequest<null>(
+				`/api/v1/admin/apps/${encodeURIComponent(idOrSlug)}/members/${userId}`,
+				{ method: 'DELETE' }
+			)
+	},
+
 	execute: async (
 		id: string,
 		body: unknown,

dashboard/src/routes/apps/[slug]/+page.svelte

@@ -5,26 +5,38 @@
 	import {
 		api,
 		ApiError,
+		type AdminDto,
 		type App,
 		type AppDomain,
+		type AppMemberDto,
+		type AppRole,
 		type Script
 	} from '$lib/api';
 	import CodeEditor from '$lib/CodeEditor.svelte';
 	import ConfirmModal from '$lib/ConfirmModal.svelte';
+	import ActionMenu from '$lib/ActionMenu.svelte';
+	import RoleChip from '$lib/RoleChip.svelte';
+	import { currentUser } from '$lib/auth';
+
+	const me = $derived($currentUser);
 
 	const SAMPLE_SOURCE =
 		'#{\n  statusCode: 200,\n  body: #{ ok: true, echo: ctx.request.body }\n}';
 
-	type Tab = 'scripts' | 'domains' | 'settings';
+	type Tab = 'scripts' | 'domains' | 'members' | 'settings';
 
 	let slug = $derived(page.params.slug ?? '');
 	let app = $state<App | null>(null);
+	let myRole = $state<AppRole | null>(null);
 	let loadError = $state<string | null>(null);
 	let loading = $state(true);
 	let activeTab = $state<Tab>('scripts');
 
 	let scripts = $state<Script[]>([]);
 	let domains = $state<AppDomain[]>([]);
+	let members = $state<AppMemberDto[]>([]);
+
+	const canAdminMembers = $derived(myRole === 'app_admin');
 
 	// Script create
 	let showCreateScript = $state(false);
@@ -55,6 +67,19 @@
 	let removingDomain = $state(false);
 	let removeDomainError = $state<string | null>(null);
 
+	// Members tab
+	let eligibleUsers = $state<AdminDto[]>([]);
+	let eligibleLoadError = $state<string | null>(null);
+	let addMemberUserId = $state('');
+	let addMemberRole = $state<AppRole>('viewer');
+	let addingMember = $state(false);
+	let addMemberError = $state<string | null>(null);
+	let memberToRemove = $state<AppMemberDto | null>(null);
+	let removingMember = $state(false);
+	let removeMemberError = $state<string | null>(null);
+	let roleChangeBusy = $state<string | null>(null);
+	let memberActionError = $state<string | null>(null);
+
 	async function loadApp() {
 		loading = true;
 		loadError = null;
@@ -72,10 +97,15 @@
 				created_at: fetched.created_at,
 				updated_at: fetched.updated_at
 			};
+			myRole = fetched.my_role;
 			editName = app.name;
 			editDescription = app.description ?? '';
 			editSlug = app.slug;
-			await Promise.all([loadScripts(app.id), loadDomains(app.id)]);
+			const loaders: Promise<unknown>[] = [loadScripts(app.id), loadDomains(app.id)];
+			if (canAdminMembers) {
+				loaders.push(loadMembers(app.id), loadEligibleUsers());
+			}
+			await Promise.all(loaders);
 		} catch (e) {
 			loadError = e instanceof Error ? e.message : String(e);
 		} finally {
@@ -101,6 +131,42 @@
 		}
 	}
 
+	async function loadMembers(appId: string) {
+		try {
+			members = await api.appMembers.list(appId);
+		} catch (e) {
+			members = [];
+			memberActionError = e instanceof Error ? e.message : String(e);
+		}
+	}
+
+	async function loadEligibleUsers() {
+		eligibleLoadError = null;
+		try {
+			const all = await api.admins.list();
+			// Only inactive=false members are valid invite targets — the
+			// API rejects everyone else anyway, so filter upfront.
+			eligibleUsers = all.filter(
+				(u) => u.is_active && u.instance_role === 'member'
+			);
+		} catch (e) {
+			eligibleUsers = [];
+			// member-with-app_admin can hit /apps/.../members but cannot
+			// browse /admins (gated on InstanceManageUsers). The add form
+			// will render disabled with the explanatory message below.
+			eligibleLoadError =
+				e instanceof ApiError && e.status === 403
+					? 'Only instance owners/admins can browse the user directory to invite new members.'
+					: e instanceof Error
+						? e.message
+						: String(e);
+		}
+	}
+
+	const eligibleAfterFilter = $derived(
+		eligibleUsers.filter((u) => !members.some((m) => m.user_id === u.id))
+	);
+
 	async function submitCreateScript(event: Event) {
 		event.preventDefault();
 		if (!app) return;
@@ -201,6 +267,76 @@
 		}
 	}
 
+	async function submitAddMember(event: Event) {
+		event.preventDefault();
+		if (!app || !addMemberUserId) return;
+		addingMember = true;
+		addMemberError = null;
+		try {
+			await api.appMembers.add(app.id, {
+				user_id: addMemberUserId,
+				role: addMemberRole
+			});
+			addMemberUserId = '';
+			addMemberRole = 'viewer';
+			await loadMembers(app.id);
+		} catch (e) {
+			addMemberError = e instanceof Error ? e.message : String(e);
+		} finally {
+			addingMember = false;
+		}
+	}
+
+	async function changeMemberRole(member: AppMemberDto, role: AppRole) {
+		if (!app || member.role === role) return;
+		roleChangeBusy = member.user_id;
+		memberActionError = null;
+		try {
+			await api.appMembers.setRole(app.id, member.user_id, role);
+			await loadMembers(app.id);
+		} catch (e) {
+			memberActionError = e instanceof Error ? e.message : String(e);
+		} finally {
+			roleChangeBusy = null;
+		}
+	}
+
+	function askRemoveMember(member: AppMemberDto) {
+		removeMemberError = null;
+		memberToRemove = member;
+	}
+
+	async function confirmRemoveMember() {
+		if (!app || !memberToRemove) return;
+		removingMember = true;
+		removeMemberError = null;
+		try {
+			const removedSelf = !!me && memberToRemove.user_id === me.id;
+			await api.appMembers.remove(app.id, memberToRemove.user_id);
+			memberToRemove = null;
+			if (removedSelf) {
+				// We just revoked our own access to this app; the next
+				// fetch of /apps/{slug} would 403. Bounce back to the
+				// apps list rather than render a broken tab.
+				await goto(`${base}/apps`);
+				return;
+			}
+			await loadMembers(app.id);
+		} catch (e) {
+			removeMemberError = e instanceof Error ? e.message : String(e);
+		} finally {
+			removingMember = false;
+		}
+	}
+
+	function shortDate(iso: string): string {
+		try {
+			return new Date(iso).toLocaleDateString();
+		} catch {
+			return iso;
+		}
+	}
+
 	function askDeleteApp() {
 		deleteAppError = null;
 		confirmingDeleteApp = true;
@@ -258,6 +394,13 @@
 			class:active={activeTab === 'domains'}
 			onclick={() => (activeTab = 'domains')}>Domains ({domains.length})</button
 		>
+		{#if canAdminMembers}
+			<button
+				type="button"
+				class:active={activeTab === 'members'}
+				onclick={() => (activeTab = 'members')}>Members ({members.length})</button
+			>
+		{/if}
 		<button
 			type="button"
 			class:active={activeTab === 'settings'}
@@ -365,6 +508,121 @@
 				</ul>
 			{/if}
 		</section>
+	{:else if activeTab === 'members' && canAdminMembers}
+		<section>
+			<h2>Members</h2>
+			<p class="muted">
+				Users with explicit access to this app. Instance owners and admins
+				already have implicit access — they are not listed here. Use the Users
+				page to invite a <code>member</code> first, then grant them app access
+				below.
+			</p>
+
+			<form class="create-form" onsubmit={submitAddMember}>
+				<div class="row">
+					<label class="grow">
+						<span>User</span>
+						<select
+							bind:value={addMemberUserId}
+							disabled={!!eligibleLoadError || eligibleAfterFilter.length === 0}
+							required
+						>
+							<option value="" disabled>Pick a member to invite…</option>
+							{#each eligibleAfterFilter as u (u.id)}
+								<option value={u.id}>{u.username}{u.email ? ` (${u.email})` : ''}</option>
+							{/each}
+						</select>
+					</label>
+					<label>
+						<span>Role</span>
+						<select bind:value={addMemberRole} disabled={!!eligibleLoadError}>
+							<option value="viewer">viewer</option>
+							<option value="editor">editor</option>
+							<option value="app_admin">app admin</option>
+						</select>
+					</label>
+				</div>
+				{#if eligibleLoadError}
+					<p class="muted">{eligibleLoadError}</p>
+				{:else if eligibleAfterFilter.length === 0}
+					<p class="muted">
+						No eligible users to invite. Create a <code>member</code> on the Users
+						page first.
+					</p>
+				{/if}
+				{#if addMemberError}
+					<div class="error">{addMemberError}</div>
+				{/if}
+				<div class="actions">
+					<button
+						type="submit"
+						disabled={addingMember || !addMemberUserId || !!eligibleLoadError}
+					>
+						{addingMember ? 'Adding…' : 'Add member'}
+					</button>
+				</div>
+			</form>
+
+			{#if memberActionError}
+				<div class="error">{memberActionError}</div>
+			{/if}
+
+			{#if members.length === 0}
+				<p class="muted">No explicit members yet.</p>
+			{:else}
+				<div class="table">
+					<div class="row head-row">
+						<div>User</div>
+						<div>Instance</div>
+						<div>App role</div>
+						<div>Joined</div>
+						<div class="actions-col"></div>
+					</div>
+					{#each members as m (m.user_id)}
+						<div class="row member-row" class:inactive={!m.is_active}>
+							<div>
+								<strong>{m.username}</strong>
+								{#if m.email}<span class="muted">{m.email}</span>{/if}
+								{#if !m.is_active}<span class="muted">(inactive)</span>{/if}
+							</div>
+							<div><RoleChip role={m.instance_role} size="sm" /></div>
+							<div><RoleChip appRole={m.role} size="sm" /></div>
+							<div>{shortDate(m.created_at)}</div>
+							<div class="actions-col">
+								<ActionMenu
+									label="Member actions for {m.username}"
+									items={[
+										{
+											label: 'Make app admin',
+											disabled:
+												m.role === 'app_admin' || roleChangeBusy === m.user_id,
+											onClick: () => changeMemberRole(m, 'app_admin')
+										},
+										{
+											label: 'Make editor',
+											disabled:
+												m.role === 'editor' || roleChangeBusy === m.user_id,
+											onClick: () => changeMemberRole(m, 'editor')
+										},
+										{
+											label: 'Make viewer',
+											disabled:
+												m.role === 'viewer' || roleChangeBusy === m.user_id,
+											onClick: () => changeMemberRole(m, 'viewer')
+										},
+										{
+											label: 'Remove from app',
+											danger: true,
+											onClick: () => askRemoveMember(m)
+										}
+									]}
+								/>
+							</div>
+						</div>
+					{/each}
+				</div>
+			{/if}
+		</section>
 	{:else if activeTab === 'settings'}
 		<section>
 			<h2>Settings</h2>
@@ -502,6 +760,26 @@
 			{/if}
 		</ConfirmModal>
 	{/if}
+
+	{#if memberToRemove}
+		<ConfirmModal
+			title="Remove {memberToRemove.username} from {app.name}"
+			variant="danger"
+			confirmLabel="Remove member"
+			busyLabel="Removing…"
+			busy={removingMember}
+			onConfirm={confirmRemoveMember}
+			onCancel={() => (memberToRemove = null)}
+		>
+			<p>
+				<strong>{memberToRemove.username}</strong> will lose access to this
+				app. Their other app memberships and account are untouched.
+			</p>
+			{#if removeMemberError}
+				<p class="modal-error">{removeMemberError}</p>
+			{/if}
+		</ConfirmModal>
+	{/if}
 {/if}
 
 <style>
@@ -744,4 +1022,60 @@
 		border-radius: 0.5rem;
 		background: #1e0a0a;
 	}
+
+	.create-form select {
+		background: #0b1220;
+		color: #e2e8f0;
+		border: 1px solid #334155;
+		border-radius: 0.375rem;
+		padding: 0.5rem 0.75rem;
+		font: inherit;
+	}
+
+	.create-form .row > label.grow {
+		grid-column: span 2;
+	}
+
+	.table {
+		display: flex;
+		flex-direction: column;
+		gap: 0.25rem;
+	}
+
+	.table .row {
+		display: grid;
+		grid-template-columns: 2fr 1fr 1fr 1fr 3rem;
+		gap: 0.75rem;
+		padding: 0.85rem 1rem;
+		background: #1e293b;
+		border-radius: 0.375rem;
+		align-items: center;
+		margin: 0;
+	}
+
+	.table .head-row {
+		background: transparent;
+		padding: 0.25rem 1rem;
+		color: #64748b;
+		font-size: 0.75rem;
+		text-transform: uppercase;
+		letter-spacing: 0.05em;
+	}
+
+	.table .member-row.inactive {
+		opacity: 0.55;
+	}
+
+	.table .member-row strong {
+		margin-right: 0.4rem;
+	}
+
+	.table .member-row .muted {
+		font-size: 0.8rem;
+	}
+
+	.table .actions-col {
+		display: flex;
+		justify-content: flex-end;
+	}
 </style>

serverless_cloud_blueprint.md

@@ -1,7 +1,7 @@
 # Project Blueprint: Lightweight Event-Based Serverless Cloud
 
 **Status**: Phase 4 — Blueprint Complete  
-**Last Updated**: 2026-04-10  
+**Last Updated**: 2026-05-27  
 **Audience**: Solo developer (DIY self-hosted)
 
 ---
@@ -1156,6 +1156,35 @@ DELETE /api/v1/admin/api-keys/{id}   — caller's own only
 
 Every existing `/api/v1/admin/*` endpoint is re-gated from "any authed admin" to a specific `Capability`. Request/response shapes are unchanged; what changes is the set of callers each endpoint accepts (a `member` now gets 403 on app surfaces they're not part of, where before they would have been 401-or-200 depending only on session validity).
 
+### App Member Management Endpoints
+
+Exposes the `app_members` table as a first-class CRUD surface so app admins can manage who they share an app with from the dashboard, not just from SQL.
+
+```
+GET    /api/v1/admin/apps/{id_or_slug}/members              — list members (ordered by username),
+                                                              joined with admin_users for
+                                                              username / email / instance_role / is_active
+POST   /api/v1/admin/apps/{id_or_slug}/members              — { user_id, role } → 201 enriched DTO
+                                                              409 on duplicate (promotions go through PATCH)
+                                                              422 if target user is_active = false
+                                                              422 if target user instance_role != 'member'
+                                                                  (owners/admins have implicit authority;
+                                                                  an explicit row would be dead weight)
+PATCH  /api/v1/admin/apps/{id_or_slug}/members/{user_id}    — { role } → 200 enriched DTO
+                                                              404 if no existing membership
+DELETE /api/v1/admin/apps/{id_or_slug}/members/{user_id}    — 204 (idempotent — 204 also when missing)
+```
+
+All four are gated on `Capability::AppAdmin(app_id)`. Editors and viewers get 403 on list and never see the dashboard's Members tab.
+
+**`my_role` on the app lookup endpoint.** `GET /api/v1/admin/apps/{id_or_slug}` now returns an additional `my_role: Option<AppRole>`, computed server-side from the principal: `Owner → app_admin`, `Admin → editor`, `Member → app_members.role`. The dashboard uses this single field to decide whether to render the Members tab (visible iff `my_role == app_admin`), keeping API and UI gate logic identical.
+
+**No last-app-admin guard.** Unlike the last-owner protection on `admin_users`, removing the final `app_admin` row from `app_members` is allowed. Every `owner` instance-role user implicitly satisfies `Capability::AppAdmin(_)` via the top-level `role_grants` branch, so no app can become permanently orphaned — an owner can always re-issue grants. The `admin` instance role is only implicit *editor*, so it does **not** provide a fallback path; the owner guarantee alone is what makes the no-guard position safe.
+
+**Dead-row sweep on promotion (deferred).** Promoting a user from `member` → `admin`/`owner` leaves their `app_members` rows in place. They become inert (implicit grants supersede), but are not auto-deleted. A future hook can sweep them; harmless for now.
+
+Additive within `/api/v1/admin/...` — no API major bump per [docs/versioning.md](docs/versioning.md).
+
 ### Out of Scope (Phase 3.5)
 
 Schema room only, not built:
@@ -1164,7 +1193,7 @@ Schema room only, not built:
 - **MFA / TOTP** — `mfa_secret` column reserved on `admin_users`.
 - **Service accounts** — reserved as a future table; for now, every API key belongs to a human `admin_users` row.
 
-Defer to follow-up sessions: dashboard surfaces for invites / member management / key minting (curl is the supported interface this phase), OIDC / SAML / SCIM, the `picloud` CLI binary itself, email/SMTP delivery of invites, audit log shipping.
+Defer to follow-up sessions: dashboard surfaces for invites / key minting (curl is the supported interface this phase — member management has a dashboard tab; see above), OIDC / SAML / SCIM, the `picloud` CLI binary itself, email/SMTP delivery of invites, audit log shipping.
 
 ---