Register the self-hosted Sentry MCP server and keep OAuth sign-ins across updates

link-mcp gains a stdio transport: the servers row names a launcher under user/agents/mcp/, run from the checkout so every machine runs the same script, and the token reaches it as MCP_TOKEN. sentry-gbrown is the first, pointing Sentry's MCP server at sentry.gbrown.org with a read-only token from the ignored env file.

A server already registered exactly as its row would register it is now left alone. Re-adding it every run threw away the sign-in of the OAuth servers, bill-tracker and atlassian, on every update.

setup/scripts/link-mcp

@@ -2,7 +2,8 @@
 
 # MCP servers, registered with the agent runtimes on this machine.
 #
-# An MCP server is a URL plus a bearer token, and the token is the whole reason
+# An MCP server is a URL plus a bearer token (or, for a stdio server, a launcher
+# script plus a token), and the token is the whole reason
 # this is a stage rather than a manifest line. Panama is a public repository, so
 # the tokens cannot live in it, and neither runtime keeps its server list in a
 # file that could be symlinked anyway: Codex writes them into config.toml beside
@@ -62,17 +63,14 @@ fi
 registered=0
 skipped=0
 
-while read -r name transport url token_var _rest; do
+while read -r name transport target token_var _rest; do
     case "${name:-}" in ''|'#'*) continue ;; esac
-    if [[ -z "${transport:-}" || -z "${url:-}" ]]; then
+    if [[ -z "${transport:-}" || -z "${target:-}" ]]; then
         warn "Ignoring malformed row for '$name'."
         continue
     fi
 
-    # The token normally travels as an Authorization header. A server that only
-    # reads it from the query string (Penpot's userToken) marks the spot with
-    # {TOKEN} in its URL instead, and gets no header.
-    header=()
+    token=""
     if [[ -n "${token_var:-}" ]]; then
         token="${!token_var:-}"
         if [[ -z "$token" ]]; then
@@ -80,20 +78,66 @@ while read -r name transport url token_var _rest; do
             skipped=$((skipped + 1))
             continue
         fi
+    fi
+
+    # An http server's token normally travels as an Authorization header. One
+    # that only reads it from the query string (Penpot's userToken) marks the
+    # spot with {TOKEN} in its URL instead, and gets no header. A stdio server's
+    # target is a launcher under user/agents/mcp/, run from this checkout so
+    # every machine runs the same script, and its token arrives as MCP_TOKEN.
+    url="$target"
+    args=()
+    if [[ "$transport" == stdio ]]; then
+        launcher="$MCP_DIR/$target"
+        if [[ ! -x "$launcher" ]]; then
+            warn "Skipping $name: $launcher is not an executable launcher."
+            skipped=$((skipped + 1))
+            continue
+        fi
+        [[ -n "$token" ]] && args=(-e "MCP_TOKEN=$token")
+    elif [[ -n "$token" ]]; then
         if [[ "$url" == *'{TOKEN}'* ]]; then
             url="${url//\{TOKEN\}/$token}"
         else
-            header=(-H "Authorization: $token")
+            args=(-H "Authorization: $token")
         fi
     fi
 
-    # Re-registering is how this stays idempotent across upgrades, and how a
-    # rotated token reaches the runtime. Removing first avoids the CLI refusing
-    # a name it already knows. Neither call may print the token, so both are
-    # quiet unless they fail.
+    # A server already registered exactly as this row would register it is left
+    # alone. Removing and re-adding it would throw away the OAuth session of a
+    # server that signs in on its own (bill-tracker, atlassian), so every
+    # upgrade would sign them out again.
+    if [[ "$transport" == stdio ]]; then
+        want="$(jq -cn --arg c "$launcher" --arg t "$token" \
+            '{command: $c, env: (if $t == "" then null else {MCP_TOKEN: $t} end)}')"
+        have="$(jq -c --arg n "$name" \
+            '.mcpServers[$n] // {} | {command, env: (if (.env // {}) == {} then null else .env end)}' \
+            "$HOME/.claude.json" 2>/dev/null || true)"
+    else
+        auth=""
+        [[ "${args[0]:-}" == -H ]] && auth="${args[1]#Authorization: }"
+        want="$(jq -cn --arg u "$url" --arg a "$auth" \
+            '{url: $u, auth: (if $a == "" then null else $a end)}')"
+        have="$(jq -c --arg n "$name" \
+            '.mcpServers[$n] // {} | {url, auth: (.headers.Authorization // null)}' \
+            "$HOME/.claude.json" 2>/dev/null || true)"
+    fi
+    if [[ -n "$have" && "$have" == "$want" ]]; then
+        log "Already registered $name."
+        registered=$((registered + 1))
+        continue
+    fi
+
+    # Re-registering is how a new server or a rotated token reaches the
+    # runtime. Removing first avoids the CLI refusing a name it already knows.
+    # Neither call may print the token, so both are quiet unless they fail.
     claude mcp remove "$name" -s user >/dev/null 2>&1 || true
-    if claude mcp add --transport "$transport" "$name" "$url" "${header[@]}" \
-        -s user >/dev/null 2>&1; then
+    if [[ "$transport" == stdio ]]; then
+        add=(claude mcp add "$name" -s user "${args[@]}" -- "$launcher")
+    else
+        add=(claude mcp add --transport "$transport" "$name" "$url" "${args[@]}" -s user)
+    fi
+    if "${add[@]}" >/dev/null 2>&1; then
         log "Registered $name."
         registered=$((registered + 1))
     else