Execute a single command on a Linux host via SSH with an ephemeral credential. Prefer this tool over ssh_session_open when you only need to run one command or independent commands. Returns stdout, stderr and exit_code. exit_code != 0 means remote command failure, NOT a tool error; treat it like a process that exits with an error. BEFORE calling: use ssh_list_servers to learn the host capabilities. sudo=true ONLY if allow_sudo=true; if allow_sudo=false, DO NOT retry with sudo and inform the user. pty=true ONLY if allow_pty=true and the command needs a TTY (with pty, stdout and stderr are merged). ttl_seconds is optional; omit to use the maximum allowed by the host policy.

Read a file from a Linux host via SSH with an ephemeral credential. Returns the content as text, or base64 (base64=true in the result) when the file is not valid UTF-8. REQUIRES allow_file_transfer=true on the host (see ssh_list_servers); if false DO NOT retry, the signer will reject it. The read runs as the host's configured SSH user (no sudo); the file must be readable by that user. A file larger than max_bytes (default: the broker's file_transfer_max_bytes, 512 KiB) is an ERROR, not a truncation. The content's sha256 is recorded in the audit log.

List the hosts accessible to the caller with their capabilities (hosts outside the user's RBAC groups are not listed). ALWAYS call before ssh_execute or ssh_session_open. Fields per host: allow_sudo=true → the host accepts NOPASSWD sudo elevation (sudo=true may be used); allow_sudo=false → DO NOT attempt sudo, the signer will reject it. allow_pty=true → the host accepts PTY (pty=true or mode=pty may be used); allow_pty=false → DO NOT attempt PTY. allow_file_transfer=true → ssh_put_file and ssh_get_file may be used; allow_file_transfer=false → DO NOT attempt file transfers, the signer will reject them. jump → name of the bastion through which the host is reached (informational).

Write a file on a Linux host via SSH with an ephemeral credential. Creates or OVERWRITES the destination file with the given content. Use content_base64=true for binary data (the content field is decoded before writing). REQUIRES allow_file_transfer=true on the host (see ssh_list_servers); if false DO NOT retry, the signer will reject it. The write runs as the host's configured SSH user (no sudo); the destination must be writable by that user. On hosts with a command policy the transfer command (cat > path) must also be allowed by the policy. Content is limited by the broker's file_transfer_max_bytes (default 512 KiB). The content's sha256 is recorded in the audit log.

Close a persistent SSH session and release the connection. Always call when done working with a session; an unclosed session keeps its SSH connection until it is reaped by the idle or maximum-lifetime timeout (not by the certificate TTL).

Execute a command in a session opened with ssh_session_open. Returns stdout, stderr and exit_code. exit_code != 0 means remote command failure, NOT a tool error. The command is preflighted against the current signer policy before execution; target and bastion access, end-user groups, sudo, sudo_user, PTY, and the host's physical route are revalidated, and audit-mode policy warnings are returned in warnings. If a policy is enabled after a shell/pty session was opened, later commands in that session are rejected. Session state (current directory, environment variables) persists across calls when mode=shell or mode=pty.

Open a persistent SSH session that reuses the connection across commands. Use when you need multiple commands with shared state (e.g. cd to a directory and then operate in it) or interactive programs. For isolated commands prefer ssh_execute (simpler, stronger isolation guarantee). Available modes: exec (default, independent commands), shell (stateful sh: cd and variables persist), pty (shell with TTY for interactive programs). sudo=true ONLY if allow_sudo=true (see ssh_list_servers); if allow_sudo=false DO NOT retry. mode=pty ONLY if allow_pty=true. Every ssh_session_exec is preflighted against the current signer policy, so policy reloads revalidate target and bastion access, end-user groups, sudo, sudo_user, PTY, and the host's physical route for already-open sessions. On command-policy hosts, mode=exec is allowed; mode=shell and mode=pty are rejected. Returns session_id for use with ssh_session_exec. IMPORTANT: always close the session with ssh_session_close when done; an open session holds an SSH connection and is otherwise closed only after an idle or maximum-lifetime timeout (it is NOT bound to the certificate TTL).