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check_files

Read-onlyIdempotent

Run Oxlint and TypeScript diagnostics on specific files, using content-hash caching to skip unchanged files. Use for incremental checks after editing, avoiding full project scans.

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

TableJSON Schema

Name	Required	Description	Default
`files`	Yes

Output Schema

TableJSON Schema

Name	Required	Description	Default
`code`	No
`engine`	No
`status`	Yes
`engines`	No
`message`	No
`clusters`	No
`truncated`	No
`loopWarning`	No
`totalIssues`	No
`schemaVersion`	No
`fileRuleChurnWarning`	No

Schema Changelog

Changes observed during successful MCP inspections.

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

A4.8/5.0

Behavior5/5

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

The description adds substantial behavioral detail beyond the annotations: content-hash-based caching, dependency on config files like .oxlintrc and tsconfig.json, and the whole-program re-run behavior of TypeScript. It also confirms no files are modified, which complements the readOnlyHint without contradicting it.

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?

The description is longer than average, but every clause earns its place: it covers purpose, usage context, path constraints, caching behavior, and engine-specific nuances. The use guidance is appropriately placed near the beginning, and the caching details are grouped logically. It is thorough but not bloated.

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 presence of a clear output schema and robust annotations, the description covers everything an agent needs to decide whether and how to call this tool: purpose, engine behavior, input constraints, error conditions, caching semantics, and sibling distinction. No critical operational context is missing.

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

Parameters4/5

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

The schema only says 'files' is an array of non-empty strings, so the description carries the burden of explaining path semantics. It does this well by specifying relative paths, excluding glob patterns, and warning about absolute/outside-root paths. This is strong but not exhaustive; it could also clarify whether directories are accepted, though the word 'files' likely implies not.

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?

The description opens with a specific action — running Oxlint, TypeScript, and optionally Biome diagnostics on a specific file list — and clearly distinguishes itself from check_project by framing this tool as the incremental variant. An agent can immediately understand what the tool does and how it differs from its nearest sibling.

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?

It explicitly instructs when to use this tool ('after editing specific files') and when to use the alternative ('use check_project for a full project scan'). It also gives concrete constraints on expected inputs, such as relative paths and no glob patterns, so an agent has actionable selection and invocation guidance.

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

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