CodeScene Code Health Rules Skill

CodeScene Code Health Rules

CodeScene evaluates 25+ code health factors and aggregates them into a 1–10 score. You control that behaviour via two mechanisms:

.codescene/code-health-rules.json — repo-scoped (or global) overrides for rule weights and low-level thresholds.
@codescene source directives — per-function suppression as inline comments.

Workflow

When the user asks to generate or modify code-health-rules.json:

Clarify scope — which files/paths need different rules? (test vs src, a specific language, a legacy subdirectory?)
Clarify intent per rule — disable entirely (0.0), down-weight (0.1–0.9), or tighten/loosen a raw threshold?
Start from CodeScene's template if available — a documented JSON template is downloadable via the Hotspots section of the project configuration; remove any rules that should stay at defaults.
Emit only the overrides — omit rules the user wants to keep at their defaults; this is how CodeScene itself recommends it, and it reduces config drift.
Place the file at .codescene/code-health-rules.json in the repo root and commit it alongside application code.

JSON Schema

{
  "usage": "optional human note — ignored by CodeScene",
  "rule_sets": [
    {
      // Required. Glob relative to repo root. Examples:
      //   "**"           → all files
      //   "test/**"      → top-level test directory
      //   "**/*.js"      → all JavaScript files
      //   "src/legacy/**" → specific subtree
      "matching_content_path": "<glob>",

      // Optional — a prose note for humans, ignored by CodeScene.
      "matching_content_path_doc": "Why this rule set exists",

      // Zero or more rule weight overrides.
      // Omit rules you want at their defaults.
      "rules": [
        {
          "name": "<exact rule name>",  // See references/rules-catalogue.md
          "weight": 0.5                 // 0.0 = disabled, 0.1–0.9 = partial, 1.0 = default
        }
      ],

      // Zero or more low-level threshold overrides.
      // Only needed for granular control inside compound rules.
      "thresholds": [
        {
          "name": "<threshold key>",    // See references/thresholds.md
          "value": 10
        }
      ]
    }
  ]
}

Multiple rule_sets are allowed in one file — each matching a different glob.

Precedence

local .codescene/code-health-rules.json
  ↳ global rules repo (configured in Project > Hotspots)
      ↳ CodeScene built-in defaults

A local repo file always wins. Global rules come from one designated repository, set via the "Repository with global code health rules" field in the Hotspots tab of the project configuration. When updating global rules, trigger a full analysis before delta analyses pick up the changes.

Weight Semantics

| weight | Effect | | -------- | ---------------------------------------------------------------- | | 1.0 | Default impact (no need to specify) | | 0.5 | Rule still fires; contributes at 50% of default severity | | 0.1 | Near-invisible; useful for "track but don't fail PR gates" | | 0.0 | Rule disabled: excluded from score, virtual review, and PR gates |

Consequences of disabling a rule (all three apply at weight: 0.0):

The rule leaves the code health calculation entirely, so the reported score can look better than the previously reported baseline.
The rule is not presented in the virtual code review.
The rule is not supervised by delta analysis or PR quality gates.

For transparency, CodeScene shows a searchable summary of all overridden rules under the Scope section of each analysis, and overridden thresholds appear in the virtual code review of every impacted file.

Do not disable the critical rules — see references/rules-catalogue.md for which rules are advisory vs critical. Disabling a critical rule means you lose early warning on the findings most correlated with defect density.

Common Patterns

Test code leniency

{
  "rule_sets": [
    {
      "matching_content_path": "test/**",
      "rules": [
        { "name": "Large Method",               "weight": 0.0 },
        { "name": "Large Assertion Blocks",     "weight": 0.0 },
        { "name": "Duplicated Assertion Blocks","weight": 0.0 },
        { "name": "Brain Method",               "weight": 0.5 }
      ],
      "thresholds": [
        { "name": "function_cyclomatic_complexity_warning", "value": 15 }
      ]
    }
  ]
}

Language-specific overrides

{
  "rule_sets": [
    {
      "matching_content_path": "**/*.js",
      "matching_content_path_doc": "JS files — allow some Primitive Obsession given dynamic typing",
      "rules": [
        { "name": "Primitive Obsession", "weight": 0.3 }
      ]
    }
  ]
}

Multi-scope config (src + test + legacy)

{
  "rule_sets": [
    {
      "matching_content_path": "**",
      "rules": [
        { "name": "Developer Congestion", "weight": 0.5 }
      ]
    },
    {
      "matching_content_path": "test/**",
      "rules": [
        { "name": "Large Assertion Blocks",      "weight": 0.0 },
        { "name": "Duplicated Assertion Blocks", "weight": 0.0 }
      ]
    },
    {
      "matching_content_path": "src/legacy/**",
      "matching_content_path_doc": "Legacy module — tracked but not gated",
      "rules": [
        { "name": "Brain Class",  "weight": 0.3 },
        { "name": "Low Cohesion", "weight": 0.3 }
      ]
    }
  ]
}

In-Source `@codescene` Directives

For per-function suppression where a JSON config would be too broad:

// @codescene(disable:"Complex Method")
void parse_protocol_frame(Frame* f) { … }

// @codescene(disable:"Complex Method", disable:"Bumpy Road Ahead")
void execute(ProgramOptions* options) { … }

// @codescene(disable-all) Scheduled refactor — 2025-Q3
void legacy_dispatch(Event* e) { … }

Rules for directives:

A directive always applies to the function/method immediately following it.
Works for all function-level smells, and only those — cannot suppress module/file-level issues (Lines of Code, Low Cohesion, Brain Class, etc.).
The smell name must exactly match what the virtual code review shows. Unknown or misspelled names are silently ignored — no error, no suppression. Note that "Bumpy Road" appears as "Bumpy Road Ahead" in directive context.
Directives may sit inside a larger multi-line comment (e.g. a Java /** … */ doc block); they need not be a standalone comment line.
The virtual code review includes a non-blocking warning about any directives in use, together with their impact, and CodeScene flags new directives in its PR review summary. Nothing flies under the radar.

Best practices (per CodeScene's own guidance):

Be restrictive — the clear majority of code health findings are real problems that should be refactored, not suppressed.
Inspect new directives in review — the PR review summary calls them out to make this easy.
Document the rationale on the directive line, with a date, so future maintainers can reassess whether it still applies: // @codescene(disable-all) Rewrite next week (2020-01-30)

Reference Files

references/rules-catalogue.md — All named rules with category, criticality, and recommended handling
references/thresholds.md — Known threshold keys with descriptions and typical override values

Agent Skills: CodeScene Code Health Rules

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Skill Files