> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/Effect-TS/tsgo/llms.txt
> Use this file to discover all available pages before exploring further.

# Plugin options

> Complete reference for all @effect/language-service plugin options in tsconfig.json.

Configure the Effect Language Service by adding options to the `@effect/language-service` plugin entry in your `tsconfig.json`. All options are optional and fall back to their documented defaults.

## Full configuration example

```jsonc tsconfig.json theme={null}
{
  "compilerOptions": {
    "plugins": [
      {
        "name": "@effect/language-service",
        // Maps rule names to severity levels. Use {} to enable diagnostics with rule defaults. (default: {})
        "diagnosticSeverity": {},
        // When false, suggestion-level Effect diagnostics are omitted from tsc CLI output. (default: true)
        "includeSuggestionsInTsc": true,
        // When true, suggestion diagnostics do not affect the tsc exit code. (default: true)
        "ignoreEffectSuggestionsInTscExitCode": true,
        // When true, warning diagnostics do not affect the tsc exit code. (default: false)
        "ignoreEffectWarningsInTscExitCode": false,
        // When true, error diagnostics do not affect the tsc exit code. (default: false)
        "ignoreEffectErrorsInTscExitCode": false,
        // When true, disabled diagnostics are still processed so directives can re-enable them. (default: false)
        "skipDisabledOptimization": false,
        // Configures key pattern formulas for the deterministicKeys rule.
        "keyPatterns": [
          {
            "target": "service",
            "pattern": "default",
            "skipLeadingPath": ["src/"]
          },
          {
            "target": "custom",
            "pattern": "default",
            "skipLeadingPath": ["src/"]
          }
        ],
        // Enables matching constructors with @effect-identifier annotations. (default: false)
        "extendedKeyDetection": false,
        // Minimum number of contiguous pipeable transformations to trigger missedPipeableOpportunity. (default: 2)
        "pipeableMinArgCount": 2,
        // Mermaid rendering service for layer graph links. (default: "mermaid.live")
        "mermaidProvider": "mermaid.live",
        // When true, suppresses external Mermaid links in hover output. (default: false)
        "noExternal": false,
        // How many levels deep the layer graph extraction follows symbol references. (default: 0)
        "layerGraphFollowDepth": 0,
        // Controls which effectFnOpportunity quickfix variants are offered. (default: ["span"])
        "effectFn": ["span"],
        // When true, suppresses redundant return-type inlay hints on Effect generator functions. (default: false)
        "inlays": false,
        // Package names allowed to have multiple versions without triggering duplicatePackage. (default: [])
        "allowedDuplicatedPackages": [],
        // Package names that should prefer namespace imports. (default: [])
        "namespaceImportPackages": [],
        // Package names that should prefer barrel named imports. (default: [])
        "barrelImportPackages": [],
        // Package-level import aliases keyed by package name. (default: {})
        "importAliases": {},
        // Controls whether named reexports are followed at package top-level. (default: "ignore")
        "topLevelNamedReexports": "ignore"
      }
    ]
  }
}
```

## Diagnostic control

<ParamField path="diagnosticSeverity" type="Record<string, Severity>" default="{}">
  Maps rule names to severity levels, overriding each rule's built-in default. Set to `{}` to enable all diagnostics at their defaults. Valid severity values are `"error"`, `"warning"`, `"suggestion"`, `"message"`, and `"off"`.

  ```jsonc theme={null}
  "diagnosticSeverity": {
    "floatingEffect": "warning",
    "strictEffectProvide": "error",
    "globalFetch": "off"
  }
  ```
</ParamField>

<ParamField path="includeSuggestionsInTsc" type="boolean" default="true">
  When `false`, suggestion-level Effect diagnostics are omitted from `tsc` CLI output. LSP and other editor flows are not affected.
</ParamField>

<ParamField path="ignoreEffectSuggestionsInTscExitCode" type="boolean" default="true">
  When `true`, Effect suggestion and message-category diagnostics do not affect the `tsc` process exit code. The diagnostics are still reported; they just won't cause a non-zero exit.
</ParamField>

<ParamField path="ignoreEffectWarningsInTscExitCode" type="boolean" default="false">
  When `true`, Effect warning-category diagnostics do not affect the `tsc` process exit code.
</ParamField>

<ParamField path="ignoreEffectErrorsInTscExitCode" type="boolean" default="false">
  When `true`, Effect error-category diagnostics do not affect the `tsc` process exit code.
</ParamField>

<ParamField path="skipDisabledOptimization" type="boolean" default="false">
  When `true`, diagnostics that are globally disabled are still processed so that per-line or per-section `@effect-diagnostics` directive comments can re-enable them locally. Enabling this option has a performance cost proportional to the number of disabled rules.
</ParamField>

## Key detection

<ParamField path="keyPatterns" type="KeyPattern[]">
  Configures the key pattern formulas used by the `deterministicKeys` diagnostic. Each entry is an object with the following fields:

  | Field             | Type                      | Description                                                                           |
  | ----------------- | ------------------------- | ------------------------------------------------------------------------------------- |
  | `target`          | `"service"` \| `"custom"` | Whether the pattern applies to service identifiers or custom identifiers.             |
  | `pattern`         | `string`                  | The formula for deriving the key string. Use `"default"` for the built-in derivation. |
  | `skipLeadingPath` | `string[]`                | Path prefixes to strip when computing the key (e.g. `["src/"]`).                      |

  Default:

  ```jsonc theme={null}
  "keyPatterns": [
    { "target": "service", "pattern": "default", "skipLeadingPath": ["src/"] },
    { "target": "custom",  "pattern": "default", "skipLeadingPath": ["src/"] }
  ]
  ```
</ParamField>

<ParamField path="extendedKeyDetection" type="boolean" default="false">
  When `true`, the `deterministicKeys` rule also matches constructors annotated with `@effect-identifier` JSDoc tags, in addition to the standard structural detection.
</ParamField>

## Pipeable style

<ParamField path="pipeableMinArgCount" type="number" default="2">
  Minimum number of contiguous pipeable transformation calls required to trigger the `missedPipeableOpportunity` diagnostic. Increase this value to reduce noise in codebases that prefer explicit style.
</ParamField>

## Layer graph and hover

<ParamField path="mermaidProvider" type="string" default="mermaid.live">
  Mermaid rendering service used to generate Layer graph diagram links in hover output. Accepted values:

  * `"mermaid.live"` — links open on [mermaid.live](https://mermaid.live)
  * `"mermaid.com"` — links open on [mermaid.com](https://www.mermaid.com)
  * Any custom URL — the diagram payload is appended to the provided base URL
</ParamField>

<ParamField path="noExternal" type="boolean" default="false">
  When `true`, external links (such as Mermaid diagram URLs) are suppressed from hover output. Useful in air-gapped environments or when external URL generation is undesirable.
</ParamField>

<ParamField path="layerGraphFollowDepth" type="number" default="0">
  How many levels deep the Layer graph extraction follows symbol references when building the hover diagram. `0` means only the immediate layer composition is shown. Higher values produce more complete graphs at the cost of analysis time.
</ParamField>

## Effect.fn quick fix variants

<ParamField path="effectFn" type="string[]" default="[&#x22;span&#x22;]">
  Controls which `effectFnOpportunity` quick fix variants are offered when the diagnostic suggests wrapping a function with `Effect.fn`. Each entry is a variant name. The only built-in variant is `"span"`.

  ```jsonc theme={null}
  "effectFn": ["span"]
  ```
</ParamField>

## Editor experience

<ParamField path="inlays" type="boolean" default="false">
  When `true`, suppresses redundant return-type inlay hints on `Effect.gen`, `Effect.fn`, and `Effect.fnUntraced` generator functions where the return type is already clear from context.
</ParamField>

## Duplicate package detection

<ParamField path="allowedDuplicatedPackages" type="string[]" default="[]">
  Package names that are permitted to appear in multiple versions without triggering the `duplicatePackage` diagnostic. Useful when a controlled multi-version scenario is intentional (e.g. migrating between major versions).

  ```jsonc theme={null}
  "allowedDuplicatedPackages": ["@effect/platform"]
  ```
</ParamField>

## Auto-import style

The four options below control how the language service suggests and organises imports. Package name matching is case-insensitive for all four options.

<ParamField path="namespaceImportPackages" type="string[]" default="[]">
  Package names that should be imported as namespace imports (`import * as X from '...'`) rather than named imports. Package matching is case-insensitive.

  ```jsonc theme={null}
  "namespaceImportPackages": ["effect", "@effect/platform"]
  ```
</ParamField>

<ParamField path="barrelImportPackages" type="string[]" default="[]">
  Package names that should use barrel named imports (`import { X } from 'package'`) rather than deep-path imports. Package matching is case-insensitive.

  ```jsonc theme={null}
  "barrelImportPackages": ["lodash"]
  ```
</ParamField>

<ParamField path="importAliases" type="Record<string, string>" default="{}">
  Maps package names to preferred local import aliases. Keys are case-insensitive package name matches; values are the alias to use in generated imports.

  ```jsonc theme={null}
  "importAliases": {
    "effect": "Effect",
    "@effect/platform": "Platform"
  }
  ```
</ParamField>

<ParamField path="topLevelNamedReexports" type="ignore | follow" default="ignore">
  Controls whether named re-exports at a package's top-level entry point are followed when resolving import candidates. Accepted values are case-insensitive; invalid values fall back to `"ignore"`.

  * `"ignore"` — re-exports are not followed; only direct exports are considered.
  * `"follow"` — re-exports are traversed to find the original export source.
</ParamField>