clarity-over-cleverness

name	clarity-over-cleverness
description	Apply clarity-over-cleverness rewrites — prefer code a junior engineer can read at a glance over compact-but-clever code. Use during `/build`'s simplify step and during `/code-simplify` (alias "simplify the code"). Never weakens behavior; suite must remain green.
when_to_use	["Phase 4 (Build) — simplify step inside `/build <task-id>`.","On-demand — user runs `/code-simplify` or says \"simplify the code\", \"make this clearer\", \"make this readable\", or \"remove the cleverness\".","During code review — flag clever code as `minor` with a suggested rewrite."]
authoritative_references	[".github/skills/spring-code-review-rubric/SKILL.md (section 8)"]

Clarity over cleverness

Rule of thumb

If a competent engineer who has never seen this code needs more than five seconds to understand a line, that line is a candidate for rewrite.

The bar is not "fewer characters". The bar is fewer surprises.

Targets (apply, in order)

1. Untangle nested ternaries

Bad:

return a ? (b ? x : y) : (c ? z : w);

Better:

if (a) {
    return b ? x : y;
}
return c ? z : w;

Best (when shapes line up):

return switch (state) {
    case ACTIVE -> x;
    case PAUSED -> y;
    case CLOSED -> z;
    case PENDING -> w;
};

2. Streams only when they read better than a loop

Bad (clever stream that's actually obscure):

return items.stream()
    .collect(Collectors.toMap(
        Item::id,
        Function.identity(),
        (a, b) -> a.timestamp().isAfter(b.timestamp()) ? a : b));

Better (explicit loop, named purpose):

Map<Id, Item> latestById = new HashMap<>();
for (Item it : items) {
    Item existing = latestById.get(it.id());
    if (existing == null || it.timestamp().isAfter(existing.timestamp())) {
        latestById.put(it.id(), it);
    }
}
return latestById;

(If the team consistently uses streams, follow the team. The point is consistency + readability, not banning streams.)

3. Inline once-used helpers

If a private method has exactly one caller AND the helper name doesn't add information, inline it. Reverse if a long method has a recognizable middle "phase" — extract that phase with a domain-meaningful name.

4. Kill option flags with one used value

Bad:

public Result calculate(Input in, boolean strict, boolean retry, Mode mode) { ... }
// every caller passes (in, true, false, Mode.DEFAULT)

Better: drop the unused dimensions; add them back when a real second caller exists.

5. Replace clever names with domain names

Bad: processX, handleData, doWork. Better: redeemGiftCard, priceWithDiscount, rejectIfExpired.

Pull names from the 01-spec.md glossary.

6. Remove premature abstraction

• Interface with one implementation, one caller, no test seam → inline the implementation.
• Generic type parameter never used by more than one type → concrete type.
• Builder for an object with two fields → constructor.

7. Prefer early return to nested if

Bad:

if (x != null) {
    if (x.valid()) {
        return x.value();
    }
}
return defaultValue;

Better:

if (x == null) return defaultValue;
if (!x.valid()) return defaultValue;
return x.value();

8. Remove unused code

The minimum code to pass the test is the right amount of code. A method with no real caller is dead weight — delete it.

Anti-pattern: "Don't add a method without a real consumer."

Tautological tests (a test that only asserts that a method returns a fixed value) do not count as a real consumer. The correct fix is to surface the design gap and test at a real API boundary.

Bad (tautological test justifying a useless wrapper):

class FeatureService {
    boolean isEnabled() { return true; }
}

@Test void isEnabled_returnsTrue() {
    assertThat(service.isEnabled()).isTrue();
}

Why bad: the test asserts nothing about real behavior. The method exists only because the test was written without a genuine consumer. The test will pass forever — it verifies nothing that would break if the feature were removed.

Better — test at the real consumer (a controller, JPA entity lifecycle, scheduled job, etc.):

// Controller calls isEnabled() to gate the endpoint
@Test void getDiscount_returns403WhenFeatureDisabled() {
    featureService.disable("discount");
    mockMvc.perform(get("/discounts")).andExpect(status().isForbidden());
}

Exemption: Framework-driven entry points (controllers, JPA @PrePersist / @PostLoad, scheduled jobs, Spring @EventListener) are legitimate consumers even when called indirectly by the framework.

9. Extract repeated literals to local constants

Any string or numeric literal that appears twice or more in the same file should be extracted to a private static final constant.

Bad:

given().post("/api/gift-cards").then().statusCode(201);
// ... later ...
given().post("/api/gift-cards").then().statusCode(409);

Better:

private static final String ENDPOINT_PATH = "/api/gift-cards";

given().post(ENDPOINT_PATH).then().statusCode(201);
// ... later ...
given().post(ENDPOINT_PATH).then().statusCode(409);

Rules:

• Threshold is 2, not 3. Extract on the second occurrence.
• Name constants with a domain-meaningful identifier (e.g., ENDPOINT_PATH, MAX_RETRIES, DEFAULT_TIMEOUT_MS).
• Place at the top of the class using private static final.
• Applies equally to test code and production code.
• Applies to numeric magic numbers too (e.g., private static final int MAX_PAGE_SIZE = 100).

What this skill never does

• Change behavior. The full suite must stay green after each rewrite.
• Reduce coverage. If a rewrite removes a branch, also remove the test asserting that branch — and verify the AC is still covered by another test.
• Touch files outside Files in scope.
• Rename public API across module boundaries (that's a refactor task, not a simplify pass).

Process inside /build's simplify step

1. Re-read the diff for the task.
2. For each function changed in green/refactor, ask: would a junior reading this for the first time understand it in five seconds?
3. If no, apply the rewrites above, one at a time, running tests between each.
4. Append a simplify block to 05-implementation-log.md for each substantive change with before/after snippets.

When the user says "simplify the code"

Treat as /code-simplify invocation:

1. Run on the currently open file OR the last-touched files in the active feature.
2. Apply the same process.
3. Suite must stay green.
4. Show the user a diff summary; do not auto-commit.