signalint

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check_files

Read-onlyIdempotent

Instructions

Runs Oxlint and TypeScript (and optionally Biome) lint and type diagnostics on a specific list of files, using per-engine content-hash caching to skip unchanged files. Read-only; no files are written or modified. Use this for incremental checks after editing specific files; use check_project for a full project scan. The files parameter expects relative file paths (not glob patterns) within the project directory — absolute paths or paths outside the root return an error response. Caching is file-content-hash-based: a file is re-checked only when its content or the engine's config file (e.g., .oxlintrc, tsconfig.json) has changed since the last call, not based on git status. TypeScript is a whole-program engine: it re-runs whenever any TypeScript file in the request has changed content.

Input Schema

Name	Required	Description	Default
`files`	Yes

Output Schema

Name	Required	Description	Default
`code`	No
`engine`	No
`status`	Yes
`checkId`	No
`engines`	No
`message`	No
`clusters`	No
`nextStep`	No
`retryable`	No
`truncated`	No
`filteredOut`	No
`loopWarning`	No
`projectRoot`	No
`totalIssues`	No
`schemaVersion`	No
`remainingIssues`	No
`filteredOutCount`	No
`omittedIssueCount`	No
`fileRuleChurnWarning`	No
`filteredOutIssueCount`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed15 schema fields changedv1.0.1Oct 13, 2026

addedOutput schema / additionalProperties
```
Added value: +false
```

changedOutput schema / properties / clusters / items / required

Previous value: -[
-  "clusterId",
-  "rootCauseSummary",
-  "ruleIds",
-  "issueCount",
-  "fileCount",
-  "priority",
-  "suggestedAction",
-  "sampleIssueIds"
-]New value: +[
+  "clusterId",
+  "rootCauseSummary",
+  "ruleIds",
+  "issueCount",
+  "fileCount",
+  "priority"
+]

changedOutput schema / properties / engine / enum

Previous value: -[
-  "oxlint",
-  "tsc",
-  "biome",
-  "eslint"
-]New value: +[
+  "oxlint",
+  "tsc",
+  "biome",
+  "eslint",
+  "external-lsp",
+  "vscode",
+  "all"
+]

addedOutput schema / properties / engines / properties / external-lsp

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "message": {
+      "type": "string"
+    },
+    "status": {
+      "enum": [
+        "ok",
+        "error",
+        "disabled"
+      ],
+      "type": "string"
+    }
+  },
+  "required": [
+    "status"
+  ],
+  "type": "object"
+}

addedOutput schema / properties / engines / properties / vscode

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "message": {
+      "type": "string"
+    },
+    "status": {
+      "enum": [
+        "ok",
+        "error",
+        "disabled"
+      ],
+      "type": "string"
+    }
+  },
+  "required": [
+    "status"
+  ],
+  "type": "object"
+}

removedOutput schema / properties / engines / required

Removed value: -[
-  "oxlint",
-  "tsc",
-  "biome",
-  "eslint"
-]

addedOutput schema / properties / filteredOut
```
Added value: +{
+  "type": "integer"
+}
```
addedOutput schema / properties / filteredOutCount
```
Added value: +{
+  "type": "integer"
+}
```
addedOutput schema / properties / filteredOutIssueCount
```
Added value: +{
+  "type": "integer"
+}
```
addedOutput schema / properties / nextStep
```
Added value: +{
+  "type": "string"
+}
```
addedOutput schema / properties / omittedIssueCount
```
Added value: +{
+  "type": "integer"
+}
```

addedOutput schema / properties / remainingIssues

Added value: +{
+  "items": {
+    "additionalProperties": false,
+    "properties": {
+      "col": {
+        "type": "integer"
+      },
+      "file": {
+        "type": "string"
+      },
+      "fixable": {
+        "type": "boolean"
+      },
+      "issueId": {
+        "type": "string"
+      },
+      "line": {
+        "type": "integer"
+      },
+      "priority": {
+        "type": "integer"
+      },
+      "rule": {
+        "type": "string"
+      },
+      "severity": {
+        "enum": [
+          "error",
+          "warning"
+        ],
+        "type": "string"
+      }
+    },
+    "required": [
+      "issueId",
+      "file",
+      "line",
+      "col",
+      "rule",
+      "severity",
+      "fixable"
+    ],
+    "type": "object"
+  },
+  "type": "array"
+}

addedOutput schema / properties / retryable
```
Added value: +{
+  "type": "boolean"
+}
```

changedOutput schema / properties / schemaVersion / enum

Previous value: -[
-  "1.3"
-]New value: +[
+  "1.3",
+  "1.4"
+]

changedOutput schema / properties / status / enum

Previous value: -[
-  "clean",
-  "issues_found",
-  "error"
-]New value: +[
+  "clean",
+  "issues_found",
+  "error",
+  "stale"
+]

Changed7 schema fields changedv1.0.0Oct 6, 2026

addedOutput schema / properties / checkId
```
Added value: +{
+  "type": "string"
+}
```

changedOutput schema / properties / engine / enum

Previous value: -[
-  "oxlint",
-  "tsc",
-  "biome"
-]New value: +[
+  "oxlint",
+  "tsc",
+  "biome",
+  "eslint"
+]

addedOutput schema / properties / engines / properties / eslint

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "message": {
+      "type": "string"
+    },
+    "status": {
+      "enum": [
+        "ok",
+        "error",
+        "disabled"
+      ],
+      "type": "string"
+    }
+  },
+  "required": [
+    "status"
+  ],
+  "type": "object"
+}

changedOutput schema / properties / engines / required

Previous value: -[
-  "oxlint",
-  "tsc",
-  "biome"
-]New value: +[
+  "oxlint",
+  "tsc",
+  "biome",
+  "eslint"
+]

addedOutput schema / properties / projectRoot
```
Added value: +{
+  "type": "string"
+}
```

changedOutput schema / properties / schemaVersion / enum

Previous value: -[
-  "1.2"
-]New value: +[
+  "1.3"
+]

changedOutput schema / properties / status / enum

Previous value: -[
-  "clean",
-  "issues_found",
-  "timeout",
-  "error"
-]New value: +[
+  "clean",
+  "issues_found",
+  "error"
+]

Changed2 schema fields changedv0.4.0Aug 21, 2026

addedOutput schema / properties / fileRuleChurnWarning

Added value: +{
+  "oneOf": [
+    {
+      "additionalProperties": false,
+      "properties": {
+        "checkCount": {
+          "type": "integer"
+        },
+        "file": {
+          "type": "string"
+        },
+        "hint": {
+          "type": "string"
+        },
+        "rule": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "file",
+        "rule",
+        "checkCount",
+        "hint"
+      ],
+      "type": "object"
+    },
+    {
+      "type": "null"
+    }
+  ]
+}

changedOutput schema / properties / schemaVersion / enum

Previous value: -[
-  "1.1"
-]New value: +[
+  "1.2"
+]

Changed1 schema field changedv0.3.7Aug 19, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "clusters": {
+      "items": {
+        "additionalProperties": false,
+        "properties": {
+          "clusterId": {
+            "type": "string"
+          },
+          "fileCount": {
+            "type": "integer"
+          },
+          "issueCount": {
+            "type": "integer"
+          },
+          "priority": {
+            "type": "integer"
+          },
+          "rootCauseSummary": {
+            "type": "string"
+          },
+          "ruleIds": {
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          },
+          "sampleIssueIds": {
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          },
+          "suggestedAction": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "clusterId",
+          "rootCauseSummary",
+          "ruleIds",
+          "issueCount",
+          "fileCount",
+          "priority",
+          "suggestedAction",
+          "sampleIssueIds"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "code": {
+      "type": "string"
+    },
+    "engine": {
+      "enum": [
+        "oxlint",
+        "tsc",
+        "biome"
+      ],
+      "type": "string"
+    },
+    "engines": {
+      "additionalProperties": false,
+      "properties": {
+        "biome": {
+          "additionalProperties": false,
+          "properties": {
+            "message": {
+              "type": "string"
+            },
+            "status": {
+              "enum": [
+                "ok",
+                "error",
+                "disabled"
+              ],
+              "type": "string"
+            }
+          },
+          "required": [
+            "status"
+          ],
+          "type": "object"
+        },
+        "oxlint": {
+          "additionalProperties": false,
+          "properties": {
+            "message": {
+              "type": "string"
+            },
+            "status": {
+              "enum": [
+                "ok",
+                "error",
+                "disabled"
+              ],
+              "type": "string"
+            }
+          },
+          "required": [
+            "status"
+          ],
+          "type": "object"
+        },
+        "tsc": {
+          "additionalProperties": false,
+          "properties": {
+            "message": {
+              "type": "string"
+            },
+            "status": {
+              "enum": [
+                "ok",
+                "error",
+                "disabled"
+              ],
+              "type": "string"
+            }
+          },
+          "required": [
+            "status"
+          ],
+          "type": "object"
+        }
+      },
+      "required": [
+        "oxlint",
+        "tsc",
+        "biome"
+      ],
+      "type": "object"
+    },
+    "loopWarning": {
+      "oneOf": [
+        {
+          "additionalProperties": false,
+          "properties": {
+            "hint": {
+              "type": "string"
+            },
+            "occurrences": {
+              "type": "integer"
+            },
+            "signature": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "signature",
+            "occurrences",
+            "hint"
+          ],
+          "type": "object"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "message": {
+      "type": "string"
+    },
+    "schemaVersion": {
+      "enum": [
+        "1.1"
+      ],
+      "type": "string"
+    },
+    "status": {
+      "enum": [
+        "clean",
+        "issues_found",
+        "timeout",
+        "error"
+      ],
+      "type": "string"
+    },
+    "totalIssues": {
+      "type": "integer"
+    },
+    "truncated": {
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "status"
+  ],
+  "type": "object"
+}

First observedv0.3.3Aug 8, 2026

TDQS

A4.9/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond annotations (readOnlyHint, idempotentHint) by explaining the content-hash caching mechanism, when files are re-checked vs skipped, that config file changes trigger re-checks, that TypeScript is a whole-program engine requiring re-runs, and that absolute/out-of-root paths produce errors.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with core purpose and sibling differentiation, then caching details. Every sentence carries useful information, though the caching explanation is detailed enough to border on verbose for the general case.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the single complex, cache-aware parameter and rich engine behavior, the description covers usage, alternative routing, path constraints, caching semantics, and engine differences. An output schema exists, so return format need not be explained.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% and there is no description of the parameter within the schema. The description fully compensates: it explains the files parameter expects relative paths (not globs), rejects absolute/out-of-root paths with an error, and implicitly scopes the list to project files.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (runs lint and type diagnostics) on a specific resource (a list of files), names the engines (Oxlint, TypeScript, Biome), and explicitly distinguishes from the sibling check_project for full scans.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states when to use this tool ('incremental checks after editing specific files') versus the alternative ('use check_project for a full project scan'). The guidance is direct and actionable.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

check_files

Instructions

Input Schema

Output Schema

Schema Changelog

TDQS

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