temporal-spring-ai: plan — discover MCP clients by type

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

Author: donald-pinckney

temporal-spring-ai/PLAN.md

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+# Plan: MCP bean lookup by type, not hard-coded name
+
+## Scope
+
+`McpPlugin.getMcpClients()` currently does:
+
+```java
+if (applicationContext.containsBean("mcpSyncClients")) {
+    Object bean = applicationContext.getBean("mcpSyncClients");
+    if (bean instanceof List<?> clientList && !clientList.isEmpty()) {
+        mcpClients = (List<McpSyncClient>) clientList;
+    }
+}
+```
+
+This is brittle:
+- Hard-coded bean name — any Spring AI rename (e.g. `mcpAsyncClients` vs
+  `mcpSyncClients`, or a future `mcpClientRegistry`) breaks the integration
+  silently.
+- Users who define additional `McpSyncClient` beans outside the Spring AI
+  auto-configuration aren't picked up.
+- The unchecked cast is a runtime landmine if anyone ever puts a
+  differently-typed `List` bean at that name.
+
+## Fix
+
+Replace with type-based lookup:
+
+```java
+Map<String, McpSyncClient> beans =
+    applicationContext.getBeansOfType(McpSyncClient.class);
+```
+
+Collect `beans.values()` into a `List<McpSyncClient>`. This picks up:
+- Whatever Spring AI's MCP auto-configuration registers today.
+- Any user-defined `McpSyncClient @Bean` declarations.
+- Any future rename by Spring AI, as long as the type stays the same.
+
+## Files to change
+
+- `src/main/java/io/temporal/springai/plugin/McpPlugin.java`
+  - Replace the `containsBean("mcpSyncClients")` block in `getMcpClients()`
+    with `applicationContext.getBeansOfType(McpSyncClient.class)`.
+  - Remove the `@SuppressWarnings("unchecked")` and the unchecked cast.
+  - Log the bean names discovered, not just the count, to aid debugging.
+  - Keep `McpClientActivityImpl`'s duplicate-name check — if two clients
+    advertise the same `clientInfo().name()`, that still needs to error.
+
+## Test plan
+
+- Unit test with a mocked `ApplicationContext.getBeansOfType` returning two
+  distinct `McpSyncClient` beans — verify both reach
+  `McpClientActivityImpl`.
+- Unit test where the context has zero `McpSyncClient` beans — verify the
+  plugin stays in the "no clients yet" state and
+  `SmartInitializingSingleton.afterSingletonsInstantiated` handles it
+  cleanly.
+
+## PR
+
+**Title:** `temporal-spring-ai: discover MCP clients by type, not by bean name`
+
+**Body:**
+
+```
+## What was changed
+`McpPlugin.getMcpClients()` now calls
+`ApplicationContext.getBeansOfType(McpSyncClient.class)` instead of
+looking up the hard-coded bean name `"mcpSyncClients"`. The unchecked
+cast is removed; discovered bean names are logged for easier debugging.
+
+## Why?
+The old bean-name lookup broke silently whenever Spring AI changed the
+name its MCP auto-configuration used, and it ignored user-defined
+`McpSyncClient` beans entirely. Type-based discovery is more robust,
+works with arbitrary user configuration, and removes an unchecked cast.
+```