Clarify singleton accessor rule only applies to zero-arg field accessors

Author: trask

.github/agents/knowledge/javaagent-singletons-patterns.md

@@ -17,7 +17,9 @@ Javaagent modules keep shared `Instrumenter` instances and related collaborators
   `"io.opentelemetry.<module-name>"`.
 - For exported collaborators, keep the field `private`, use a lower camel case field name, and
   give the accessor method the exact same name as the field. Do not prefix these accessors with
-  `get`.
+  `get`. This rule applies only to zero-arg methods that directly return a stored singleton
+  field; methods that take arguments or compute a value are not singleton accessors and keep
+  their normal names (including `get*` when appropriate).
   - `instrumenter` -> `instrumenter()`
   - `helper` -> `helper()`
   - `setter` -> `setter()`
@@ -34,6 +36,9 @@ Javaagent modules keep shared `Instrumenter` instances and related collaborators
 - Keep verb-named helper methods as verbs when they perform work instead of returning a stored
   field. These methods are not singleton accessors and should not be static imported under this
   rule.
+- Methods on a `*Singletons` class that take arguments (for example `addressAndPort(client)` or
+  `getAddressAndPort(client)`) are not singleton accessors. Do not apply the field-style
+  accessor naming rule to them, and do not flag their `get*` prefix on that basis.
 
 ## Preferred Pattern
 
@@ -103,7 +108,8 @@ class MyInstrumentation implements TypeInstrumentation {
   final` field would be clearer and matches the naming guidance, including semantic keys/handles
   and immutable value constants.
 - Accessor methods named `getInstrumenter()`, `getHelper()`, `getSetter()`, and similar when they
-  simply return a backing field.
+  simply return a backing field. Do not flag `get*`-prefixed methods that take arguments or
+  compute a value rather than returning a stored singleton field.
 - Call sites that qualify singleton accessor or uppercase constant-like field usage with the holder
   class instead of static importing the accessor or field.
 - Static imports of non-accessor helper methods on a `*Singletons` class when the method performs