SvelteLS.MCP

Instructions

Implementation Reference

• src/tools/code-actions.ts:38-83 (handler)

  The handler logic for 'get_code_actions' which fetches and formats code actions.

  async ({ filePath, startLine, endLine, kind }): Promise<ToolResult> => {
    try {
      const { actions, error } = await fetchCodeActions(
        lsp,
        filePath,
        startLine,
        endLine,
        kind
      );
      if (error) return textResult(error);
      if (!actions || actions.length === 0) {
        return textResult(
          `No code actions available at line ${startLine}` +
            (kind ? ` (kind: ${kind})` : "") +
            "."
        );
      }
  
      const lines: string[] = [
        `Found ${actions.length} code action(s) at line ${startLine}` +
          (endLine != null && endLine !== startLine
            ? `-${endLine}`
            : "") +
          ":",
        "",
      ];
  
      for (let i = 0; i < actions.length; i++) {
        const action = actions[i];
        const title = action.title ?? "?";
        const actionKind = action.kind ?? "";
        const isPreferred = action.isPreferred === true;
        const disabled = action.disabled?.reason;
  
        let entry = `  ${i + 1}. ${title}`;
        if (actionKind) entry += ` [${actionKind}]`;
        if (isPreferred) entry += " (preferred)";
        if (disabled) entry += ` (disabled: ${disabled})`;
        lines.push(entry);
      }
  
      return textResult(lines.join("\n"));
    } catch (ex) {
      return textResult(formatError(ex));
    }
  }

• src/tools/code-actions.ts:17-37 (registration)

  Registration of the 'get_code_actions' tool with its schema definition.

  server.registerTool(
    "get_code_actions",
    {
      title: "Get Code Actions",
      description:
        "List available code actions (quick fixes, refactorings) for a line or range in a file.",
      inputSchema: z.object({
        filePath: z.string().describe("Absolute path to the file"),
        startLine: z.number().describe("Start line (1-based)"),
        endLine: z
          .number()
          .optional()
          .describe("End line (1-based). Defaults to startLine"),
        kind: z
          .string()
          .optional()
          .describe(
            "Filter by kind: quickfix, refactor, refactor.extract, refactor.inline, refactor.rewrite, source, source.organizeImports, source.fixAll"
          ),
      }),
    },

• src/tools/code-actions.ts:190-224 (helper)

  Helper function that performs the actual LSP request to fetch code actions.

  async function fetchCodeActions(
    lsp: LspClient,
    filePath: string,
    startLine: number,
    endLine?: number,
    kind?: string
  ): Promise<{ actions?: any[]; error?: string }> {
    const prep = await prepareDocumentRequest(lsp, filePath);
    if ("error" in prep) return { error: prep.error };
  
    // Fetch diagnostics from cache for context
    const cachedDiags = lsp.getCachedDiagnostics(prep.uri);
    const sl = startLine - 1;
    const el = (endLine ?? startLine) - 1;
  
    const diagnosticsForRange = cachedDiags.filter((d: any) => {
      const diagStart = d.range?.start?.line ?? -1;
      const diagEnd = d.range?.end?.line ?? -1;
      return diagEnd >= sl && diagStart <= el;
    });
  
    const context: any = { diagnostics: diagnosticsForRange };
    if (kind) context.only = [kind];
  
    const result = await lsp.request("textDocument/codeAction", {
      textDocument: { uri: prep.uri },
      range: {
        start: { line: sl, character: 0 },
        end: { line: el + 1, character: 0 },
      },
      context,
    });
  
    return { actions: Array.isArray(result) ? result : [] };
  }