fix: let an admin use the connectors they implicitly hold

Activating a per-user connector as admin failed with "you are not
authorized to use this connector — ask an admin to enable it for you".

`db::access_defaults` deliberately writes no grant rows for admins, and
says why: "they already hold every plugin and connector implicitly, so a
row for them would be noise". That implicit hold was only ever
implemented for plugins (`plugin_access::effective_access`). The two MCP
grant tables had nothing but the raw junction read, so an admin ended up
with no row *and* no short-circuit — denied their own connectors, and
denied more the more the seeding was trusted to skip them.

The reported symptom was the mildest of four:

  - `activate` refused, while `available` listed the entry (an admin
    holds `mcp.manage_catalog`) — visible but unusable;
  - the login-time startup filter dropped an admin's already-activated
    catalog connectors, so they silently stopped running;
  - `accessible_global` snapshotted an empty set, so an admin's sessions
    were offered no shared MCP tools at all — no error, just absence;
  - the connector report told the agent an admin's own global connector
    was "not granted to you".

`users::is_admin` is now the single predicate behind every "admins hold
it implicitly" short-circuit, and `plugin_access` was moved onto it too:
three tables open-coding the same role lookup is what let one of them be
written without it. Each MCP table grows an `effective_access` beside its
`has_access`, and the distinction is the point — `has_access` stays the
roster question ("what did the admin tick"), which the access-editing
surfaces must keep asking, while the gates ask the authorization one.

Nothing widens for anyone else: deny-by-default is untouched for
non-admins, an unknown user is nobody, a disabled global stays excluded
for admins too, and the `not_granted` report branch survives for a
non-admin who was given the catalog-management capability.

crates/skald-core/src/db/mcp_catalog_access.rs

@@ -33,6 +33,10 @@ pub async fn users_for_catalog(pool: &SqlitePool, catalog_name: &str) -> Result<
     Ok(rows.into_iter().map(|(u,)| u).collect())
 }
 
+/// The raw junction read: is there a grant row? This is the **roster** question —
+/// what an admin ticked on somebody's page — and it is what the access-editing
+/// surfaces must show. It is *not* the authorization question; use
+/// [`effective_access`] for that.
 pub async fn has_access(pool: &SqlitePool, catalog_name: &str, user_id: &str) -> Result<bool> {
     let row = sqlx::query_as::<_, (i64,)>(
         "SELECT 1 FROM mcp_catalog_access WHERE catalog_name = ? AND user_id = ?",
@@ -44,6 +48,27 @@ pub async fn has_access(pool: &SqlitePool, catalog_name: &str, user_id: &str) ->
     Ok(row.is_some())
 }
 
+/// The authorization decision: may this user activate/run this connector?
+///
+/// The admin role holds every connector implicitly, exactly as it holds every
+/// plugin ([`super::plugin_access::effective_access`]) and every capability
+/// ([`super::role_capabilities::has`]). That implicit hold is not a convenience —
+/// [`super::access_defaults`] *depends* on it: it skips admins when seeding grants
+/// ("they already hold every plugin and connector implicitly, so a row for them
+/// would be noise"), so without a short-circuit here an admin ends up with no row
+/// and no implicit access, and is denied their own connectors. That was the bug:
+/// `available` listed a per-user connector to the admin (who holds
+/// `mcp.manage_catalog`) while `activate` refused it — visible but unusable.
+///
+/// An unknown user id resolves to `false`; errors propagate, so callers fail
+/// closed.
+pub async fn effective_access(pool: &SqlitePool, catalog_name: &str, user_id: &str) -> Result<bool> {
+    if super::users::is_admin(pool, user_id).await? {
+        return Ok(true);
+    }
+    has_access(pool, catalog_name, user_id).await
+}
+
 // ── Writes ───────────────────────────────────────────────────────────────────
 
 /// Grants a user access to a catalog entry. Idempotent on the PK.
@@ -122,6 +147,11 @@ mod tests {
             sqlx::query("INSERT INTO users (id, username, role_id, encrypted) VALUES (?, ?, 'admin', 0)")
                 .bind(id).bind(name).execute(&pool).await.unwrap();
         }
+        // A non-admin, for the effective-access tests: only `admin` is seeded.
+        sqlx::query("INSERT INTO roles (id, label, permission_group) VALUES ('member', 'Member', 'default')")
+            .execute(&pool).await.unwrap();
+        sqlx::query("INSERT INTO users (id, username, role_id, encrypted) VALUES ('m1', 'mallory', 'member', 0)")
+            .execute(&pool).await.unwrap();
         for cat in ["gmail", "pokemon"] {
             sqlx::query("INSERT INTO mcp_catalog (name, scope, source) VALUES (?, 'per_user', 'remote')")
                 .bind(cat).execute(&pool).await.unwrap();
@@ -171,4 +201,37 @@ mod tests {
 
         let _ = std::fs::remove_dir_all(&dir);
     }
+
+    #[tokio::test]
+    async fn an_admin_is_authorized_without_a_grant_row() {
+        // The regression this exists for: `access_defaults` deliberately writes no
+        // grant rows for admins, on the stated grounds that they hold every
+        // connector implicitly. Nothing implemented that here, so an admin was
+        // listed a connector (they hold `mcp.manage_catalog`) and then refused when
+        // they tried to activate it.
+        let (pool, dir) = registry_pool("admin-implicit").await;
+
+        assert!(!has_access(&pool, "gmail", "u1").await.unwrap(), "no row, by design");
+        assert!(effective_access(&pool, "gmail", "u1").await.unwrap(), "but an admin holds it");
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[tokio::test]
+    async fn a_member_still_needs_the_grant() {
+        // The other half: the short-circuit must not have widened anything for
+        // anyone else. Deny-by-default is unchanged for a non-admin.
+        let (pool, dir) = registry_pool("member-denied").await;
+
+        assert!(!effective_access(&pool, "gmail", "m1").await.unwrap());
+        grant(&pool, "gmail", "m1").await.unwrap();
+        assert!(effective_access(&pool, "gmail", "m1").await.unwrap());
+        // And a connector they were not granted stays denied.
+        assert!(!effective_access(&pool, "pokemon", "m1").await.unwrap());
+
+        // An unknown user is nobody, not an admin.
+        assert!(!effective_access(&pool, "gmail", "ghost").await.unwrap());
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
 }

crates/skald-core/src/db/mcp_global_access.rs

@@ -10,8 +10,8 @@ use sqlx::SqlitePool;
 
 // ── Reads ────────────────────────────────────────────────────────────────────
 
-/// The names of the **enabled** global servers a user may use. Feeds the
-/// `accessible_global` snapshot captured when the user's context is built.
+/// The names of the **enabled** global servers granted to a user by a row. The
+/// roster read — for the runtime set, use [`effective_server_names_for_user`].
 pub async fn server_names_for_user(pool: &SqlitePool, user_id: &str) -> Result<Vec<String>> {
     let rows = sqlx::query_as::<_, (String,)>(
         "SELECT s.name
@@ -26,6 +26,30 @@ pub async fn server_names_for_user(pool: &SqlitePool, user_id: &str) -> Result<V
     Ok(rows.into_iter().map(|(n,)| n).collect())
 }
 
+/// The enabled global servers a user may actually use. Feeds the
+/// `accessible_global` snapshot captured when the user's context is built, and so
+/// decides which shared MCP tools their agent is offered at all.
+///
+/// An admin gets every enabled server, because they are never given grant rows
+/// (see [`effective_access`]). Without this an admin's session snapshotted an
+/// empty set and simply had no shared connectors — the same root cause as being
+/// refused activation, one layer down and much quieter, since nothing errors: the
+/// tools are just absent.
+pub async fn effective_server_names_for_user(
+    pool: &SqlitePool,
+    user_id: &str,
+) -> Result<Vec<String>> {
+    if !super::users::is_admin(pool, user_id).await? {
+        return server_names_for_user(pool, user_id).await;
+    }
+    let rows = sqlx::query_as::<_, (String,)>(
+        "SELECT name FROM mcp_global_servers WHERE enabled = 1 ORDER BY name",
+    )
+    .fetch_all(pool)
+    .await?;
+    Ok(rows.into_iter().map(|(n,)| n).collect())
+}
+
 /// The ids of the users granted access to a given global server.
 pub async fn users_for_server(pool: &SqlitePool, server_id: i64) -> Result<Vec<String>> {
     let rows = sqlx::query_as::<_, (String,)>(
@@ -37,6 +61,9 @@ pub async fn users_for_server(pool: &SqlitePool, server_id: i64) -> Result<Vec<S
     Ok(rows.into_iter().map(|(u,)| u).collect())
 }
 
+/// The raw junction read: is there a grant row? This is the **roster** question —
+/// what an admin ticked on somebody's page — and it is what the access-editing
+/// surfaces must show. For "may this user use it", use [`effective_access`].
 pub async fn has_access(pool: &SqlitePool, server_id: i64, user_id: &str) -> Result<bool> {
     let row = sqlx::query_as::<_, (i64,)>(
         "SELECT 1 FROM mcp_global_access WHERE server_id = ? AND user_id = ?",
@@ -48,6 +75,19 @@ pub async fn has_access(pool: &SqlitePool, server_id: i64, user_id: &str) -> Res
     Ok(row.is_some())
 }
 
+/// The authorization decision: may this user use this shared connector?
+///
+/// Admins hold every connector implicitly — see
+/// [`super::mcp_catalog_access::effective_access`] for why that short-circuit is
+/// load-bearing rather than cosmetic (`access_defaults` skips seeding them rows
+/// precisely because it is supposed to exist).
+pub async fn effective_access(pool: &SqlitePool, server_id: i64, user_id: &str) -> Result<bool> {
+    if super::users::is_admin(pool, user_id).await? {
+        return Ok(true);
+    }
+    has_access(pool, server_id, user_id).await
+}
+
 // ── Writes ───────────────────────────────────────────────────────────────────
 
 /// Grants a user access to a global server. Idempotent on the PK.
@@ -108,3 +148,76 @@ pub async fn set_for_user(pool: &SqlitePool, user_id: &str, server_ids: &[i64])
     tx.commit().await?;
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::PathBuf;
+
+    /// A registry-schema database with one admin, one member, and two global
+    /// servers — one of them disabled, since "enabled" is part of the answer.
+    async fn registry_pool(tag: &str) -> (SqlitePool, PathBuf, i64) {
+        use std::sync::atomic::{AtomicU64, Ordering};
+        static SEQ: AtomicU64 = AtomicU64::new(0);
+        let n = SEQ.fetch_add(1, Ordering::Relaxed);
+        let dir = std::env::temp_dir()
+            .join(format!("skald-globalaccess-{}-{tag}-{n}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&dir);
+        std::fs::create_dir_all(&dir).unwrap();
+        let pool = crate::db::init_system_pool(&dir.join("system.db").to_string_lossy())
+            .await
+            .unwrap();
+
+        sqlx::query("INSERT INTO users (id, username, role_id, encrypted) VALUES ('adm', 'adm', 'admin', 0)")
+            .execute(&pool).await.unwrap();
+        sqlx::query("INSERT INTO roles (id, label, permission_group) VALUES ('member', 'Member', 'default')")
+            .execute(&pool).await.unwrap();
+        sqlx::query("INSERT INTO users (id, username, role_id, encrypted) VALUES ('mem', 'mem', 'member', 0)")
+            .execute(&pool).await.unwrap();
+
+        let sid = sqlx::query("INSERT INTO mcp_global_servers (name, enabled) VALUES ('websearch', 1)")
+            .execute(&pool).await.unwrap().last_insert_rowid();
+        sqlx::query("INSERT INTO mcp_global_servers (name, enabled) VALUES ('offline', 0)")
+            .execute(&pool).await.unwrap();
+
+        (pool, dir, sid)
+    }
+
+    #[tokio::test]
+    async fn an_admin_holds_every_enabled_global_without_a_row() {
+        let (pool, dir, sid) = registry_pool("admin-implicit").await;
+
+        assert!(!has_access(&pool, sid, "adm").await.unwrap(), "no row, by design");
+        assert!(effective_access(&pool, sid, "adm").await.unwrap());
+        // The snapshot that decides which shared MCP tools the session is offered.
+        // A disabled server is still excluded — implicit access is not a bypass of
+        // the admin having switched something off.
+        assert_eq!(
+            effective_server_names_for_user(&pool, "adm").await.unwrap(),
+            vec!["websearch"],
+        );
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[tokio::test]
+    async fn a_member_still_needs_the_grant() {
+        let (pool, dir, sid) = registry_pool("member-denied").await;
+
+        assert!(!effective_access(&pool, sid, "mem").await.unwrap());
+        assert!(effective_server_names_for_user(&pool, "mem").await.unwrap().is_empty());
+
+        grant(&pool, sid, "mem").await.unwrap();
+        assert!(effective_access(&pool, sid, "mem").await.unwrap());
+        assert_eq!(
+            effective_server_names_for_user(&pool, "mem").await.unwrap(),
+            vec!["websearch"],
+        );
+
+        // An unknown user is nobody, not an admin.
+        assert!(!effective_access(&pool, sid, "ghost").await.unwrap());
+        assert!(effective_server_names_for_user(&pool, "ghost").await.unwrap().is_empty());
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+}

crates/skald-core/src/db/plugin_access.rs

@@ -49,15 +49,10 @@ pub async fn has_access(pool: &SqlitePool, plugin_id: &str, user_id: &str) -> Re
 /// otherwise the user must be granted in `plugin_access`. An unknown user id
 /// resolves to `false`. Errors propagate — the caller fails closed.
 pub async fn effective_access(pool: &SqlitePool, plugin_id: &str, user_id: &str) -> Result<bool> {
-    let role = sqlx::query_as::<_, (String,)>("SELECT role_id FROM users WHERE id = ?")
-        .bind(user_id)
-        .fetch_optional(pool)
-        .await?;
-    match role {
-        Some((r,)) if r == crate::db::roles::ADMIN_ROLE_ID => Ok(true),
-        Some(_) => has_access(pool, plugin_id, user_id).await,
-        None    => Ok(false),
+    if crate::db::users::is_admin(pool, user_id).await? {
+        return Ok(true);
     }
+    has_access(pool, plugin_id, user_id).await
 }
 
 // ── Writes ───────────────────────────────────────────────────────────────────

crates/skald-core/src/db/users.rs

@@ -272,6 +272,24 @@ pub async fn count(pool: &SqlitePool) -> Result<i64> {
     Ok(n)
 }
 
+/// Whether this user holds the admin role — the one predicate behind every
+/// "admins hold it implicitly" short-circuit (`plugin_access`,
+/// `mcp_catalog_access`, `mcp_global_access`).
+///
+/// It lives here, as one function, because the alternative is what actually
+/// happened: each grant table open-coded the role lookup, one of them was written
+/// without it, and admins were denied their own connectors while
+/// [`super::access_defaults`] skipped seeding them rows on the grounds that the
+/// short-circuit existed. An unknown user is not an admin; errors propagate so
+/// callers fail closed.
+pub async fn is_admin(pool: &SqlitePool, user_id: &str) -> Result<bool> {
+    let role = sqlx::query_as::<_, (String,)>("SELECT role_id FROM users WHERE id = ?")
+        .bind(user_id)
+        .fetch_optional(pool)
+        .await?;
+    Ok(matches!(role, Some((r,)) if r == super::roles::ADMIN_ROLE_ID))
+}
+
 // ── Writes ────────────────────────────────────────────────────────────────────
 
 /// `id` is supplied by the caller and must be opaque (never the username), so a