linear_createComment

Add comments to Linear issues to provide updates, share information, or ask questions, using Markdown formatting for clarity.

Instructions

Add a comment to an issue in Linear

Input Schema

TableJSON Schema

Name	Required	Description	Default
`issueId`	Yes	ID or identifier of the issue to comment on (e.g., ABC-123)
`body`	Yes	Text of the comment (Markdown supported)

Implementation Reference

src/tools/handlers/issue-handlers.ts:102-115 (handler)

The handler function that implements the core logic for the linear_createComment tool. It validates the input arguments using the isCreateCommentArgs type guard and calls the LinearService to create the comment.

export function handleCreateComment(linearService: LinearService) {
  return async (args: unknown) => {
    try {
      if (!isCreateCommentArgs(args)) {
        throw new Error("Invalid arguments for createComment");
      }
      
      return await linearService.createComment(args);
    } catch (error) {
      logError("Error creating comment", error);
      throw error;
    }
  };
}

src/tools/definitions/issue-tools.ts:366-391 (schema)

Defines the tool schema for linear_createComment, specifying input (issueId, body) and output structure.

export const createCommentToolDefinition: MCPToolDefinition = {
  name: "linear_createComment",
  description: "Add a comment to an issue in Linear",
  input_schema: {
    type: "object",
    properties: {
      issueId: {
        type: "string",
        description: "ID or identifier of the issue to comment on (e.g., ABC-123)",
      },
      body: {
        type: "string",
        description: "Text of the comment (Markdown supported)",
      },
    },
    required: ["issueId", "body"],
  },
  output_schema: {
    type: "object",
    properties: {
      id: { type: "string" },
      body: { type: "string" },
      url: { type: "string" }
    }
  }
};

src/tools/handlers/index.ts:83-83 (registration)
Registers the linear_createComment tool in the handlers map by associating it with the handleCreateComment function curried with linearService.
```
linear_createComment: handleCreateComment(linearService),
```

src/tools/type-guards.ts:180-194 (schema)

Type guard function used by the handler to validate input arguments for the linear_createComment tool.

 * Type guard for linear_createComment tool arguments
 */
export function isCreateCommentArgs(args: unknown): args is {
  issueId: string;
  body: string;
} {
  return (
    typeof args === "object" &&
    args !== null &&
    "issueId" in args &&
    typeof (args as { issueId: string }).issueId === "string" &&
    "body" in args &&
    typeof (args as { body: string }).body === "string"
  );
}

Linear MCP Server