duration

Author: trask

.github/agents/knowledge/general-rules.md

@@ -15,7 +15,7 @@ When a "Knowledge File" is listed, load it from `knowledge/` before reviewing th
 | --- | --- | --- | --- |
 | General | Logic, correctness, reliability, safety, copy/paste mistakes, incorrect comments | Always | — |
 | Style | Style guide | Always | — |
-| Style | Uppercase field names should reflect semantic constants, not simply `static final` | Always | — |
+| Style | Uppercase field names should reflect semantic constants or immutable value constants such as `Duration` timeouts/intervals, not simply `static final` | Always | — |
 | Naming | Getter naming (`get` / `is`) | Always | — |
 | Naming | Module/package naming | New or renamed modules/packages | `module-naming.md` |
 | Javaagent | Advice patterns | `@Advice` classes | `javaagent-advice-patterns.md` |

docs/contributing/style-guide.md

@@ -95,11 +95,13 @@ Method parameters and local variables should never be declared `final`.
 ### Uppercase field names
 
 Use uppercase (`SCREAMING_SNAKE_CASE`) for constant-like fields whose value is treated as a stable
-identifier or immutable descriptor.
+identifier, immutable descriptor, or immutable value constant.
 
 Examples that may remain uppercase include:
 
 - literal strings, numbers, and booleans that behave like module constants
+- immutable value objects that are treated as fixed constants after initialization, such as
+  `Duration` timeouts, intervals, or deadlines
 - semantic keys and handles such as `AttributeKey`, `ContextKey`, `VirtualField`,
   `MethodHandle`, and `Pattern`
 - canonical singleton or sentinel fields named `INSTANCE`, `EMPTY`, or `NOOP`
@@ -110,6 +112,12 @@ Use lower camel case for runtime-created collaborator objects even when they are
 for example loggers, instrumenters, helpers, sanitizers, mappers, caches, and similar service
 objects.
 
+When deciding between uppercase and lower camel case, distinguish immutable value constants from
+collaborators. A `private static final Duration FLUSH_TIMEOUT = ...;` field may remain uppercase
+when it is used as a fixed timeout constant, even if its value is computed from configuration at
+startup. In contrast, runtime-created service objects such as instrumenters, tracers, loggers, or
+helpers should use lower camel case.
+
 ### `@Nullable` annotation usage
 
 **Note: This section is aspirational and may not reflect the current codebase.**