Tmux MCP Server

Instructions

Implementation Reference

• src/index.ts:554-569 (handler)

  The handler function for tmux_kill_pane tool. It constructs the target from session, window, and pane, then executes the tmux kill-pane command via runTmux utility.

  async ({ session, window, pane }) => {
    try {
      const target = formatTarget(session, window, pane);
      await runTmux(`kill-pane -t "${target}"`);
  
      return {
        content: [{ type: "text", text: `Pane ${pane} killed successfully.` }],
        structuredContent: { success: true, session, window, pane },
      };
    } catch (error) {
      return {
        content: [{ type: "text", text: error instanceof Error ? error.message : String(error) }],
        isError: true,
      };
    }
  }

• src/index.ts:540-547 (schema)

  Input schema validation for the tmux_kill_pane tool using Zod, defining parameters session, window (optional), and pane.

  inputSchema: z
    .object({
      session: z.string().min(1).describe("Name of the session"),
      window: z.union([z.string(), z.number()]).optional().describe("Window index or name"),
      pane: z.number().int().min(0).describe("Pane index"),
    })
    .strict(),
  annotations: {

• src/index.ts:528-570 (registration)

  Full registration of the tmux_kill_pane tool with McpServer, including title, description, schema, annotations, and handler function.

  server.registerTool(
    "tmux_kill_pane",
    {
      title: "Kill tmux Pane",
      description: `Kill (close) a pane in a tmux window.
  
  Args:
    - session (string, required): Name of the session
    - window (string or number, optional): Window index or name
    - pane (number, required): Pane index
  
  WARNING: This will terminate the process running in the pane.`,
      inputSchema: z
        .object({
          session: z.string().min(1).describe("Name of the session"),
          window: z.union([z.string(), z.number()]).optional().describe("Window index or name"),
          pane: z.number().int().min(0).describe("Pane index"),
        })
        .strict(),
      annotations: {
        readOnlyHint: false,
        destructiveHint: true,
        idempotentHint: true,
        openWorldHint: false,
      },
    },
    async ({ session, window, pane }) => {
      try {
        const target = formatTarget(session, window, pane);
        await runTmux(`kill-pane -t "${target}"`);
  
        return {
          content: [{ type: "text", text: `Pane ${pane} killed successfully.` }],
          structuredContent: { success: true, session, window, pane },
        };
      } catch (error) {
        return {
          content: [{ type: "text", text: error instanceof Error ? error.message : String(error) }],
          isError: true,
        };
      }
    }
  );

• src/index.ts:70-82 (helper)

  Helper function used by tmux_kill_pane to format the tmux target string (session:window.pane).

  function formatTarget(session?: string, window?: number | string, pane?: number): string {
    let target = "";
    if (session) {
      target = session;
      if (window !== undefined) {
        target += `:${window}`;
        if (pane !== undefined) {
          target += `.${pane}`;
        }
      }
    }
    return target;
  }

• src/index.ts:45-68 (helper)

  Utility function to execute tmux commands asynchronously, handling common tmux errors gracefully.

  async function runTmux(args: string): Promise<string> {
    try {
      const { stdout } = await execAsync(`tmux ${args}`);
      return stdout.trim();
    } catch (error: unknown) {
      if (error instanceof Error && "stderr" in error) {
        const stderr = (error as { stderr: string }).stderr;
        if (stderr.includes("no server running")) {
          throw new Error("tmux server is not running. Start a session first with tmux_create_session.");
        }
        if (stderr.includes("session not found")) {
          throw new Error("Session not found. Use tmux_list_sessions to see available sessions.");
        }
        if (stderr.includes("window not found")) {
          throw new Error("Window not found. Use tmux_list_windows to see available windows.");
        }
        if (stderr.includes("can't find pane")) {
          throw new Error("Pane not found. Use tmux_list_panes to see available panes.");
        }
        throw new Error(`tmux error: ${stderr}`);
      }
      throw error;
    }
  }