Jaroslav Beneš
4ced049ff8
An agent chat will act on a machine you choose, so this is the screen where you choose it. User-owned like a note, not admin-owned like a connection: these are somebody's own machines and somebody's own keys, and "anyone in this group may log in to my server" is a different feature with a different blast radius. services/sharing.py is deliberately not involved either -- sharing grants reading, and a host somebody else can read is a host they can log in to. Trust on first use, made explicit rather than assumed. Adding a host does not connect to it. Check looks at its key and shows you the fingerprint; nothing is sent until you accept, because get_server_host_key completes the key exchange and stops -- no username, no credential. Accepting pins it, and a host that later presents a different key is refused with the reason rather than quietly trusted. Moving a profile to another host or port forgets the pin, since a key belongs to the machine it came from. Four asyncssh defaults are actively wrong here and all four are passed explicitly: every LLeMbas user shares one unix account, so `known_hosts` would be a shared trust store, `client_keys` would authenticate one person with another's key, `config` would let a ProxyCommand redirect the connection, and `agent_path` would silently use $SSH_AUTH_SOCK. There is a test for exactly that, and it needs no server. Files go over SFTP rather than through a shell. The SSH exec protocol carries one command *string* that the far side parses, with no argv form at all, so a model-supplied path in a command line is unavoidably a quoting problem. Over SFTP a path is a path. Chat gains its kind, connection, project directory and mode; the first three are fixed once a chat has a message, because a transcript whose earlier turns ran somewhere else is not one conversation. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
120 lines
3.7 KiB
Python
120 lines
3.7 KiB
Python
"""What an agent chat needs from the machine it acts on.
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One interface, currently one implementation. It exists as an interface anyway
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because the *snapshot* is the load-bearing part: a generation outlives the
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request that started it, so everything a runner needs -- the host, the decrypted
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credential, the mode, the project directory -- has to be read while the session
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is open and carried, not looked up later. That is the same reason `Endpoint` is
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a frozen copy of a `Connection` and `ToolContext` holds an owner id rather than
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a `User`.
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"""
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from __future__ import annotations
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import re
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from dataclasses import dataclass, field
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from typing import Any, Protocol
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# What a command may weigh before it is cut off. Per call; the reply also has a
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# total, in policy.Limits.
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DEFAULT_MAX_BYTES = 64 * 1024
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DEFAULT_TIMEOUT = 60.0
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# Terminal escape sequences, stripped from anything a command produced. They are
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# inert in escaped HTML, but this text also re-enters the model's context, where
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# they are a known way of hiding instructions, and it may end up in a log a
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# person later cats, where they hijack the terminal.
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_ANSI = re.compile(r"\x1b\[[0-9;?]*[ -/]*[@-~]|\x1b\][^\x07\x1b]*(?:\x07|\x1b\\)|\x1b[@-Z\\-_]")
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@dataclass(frozen=True)
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class ExecRequest:
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"""One command to run."""
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command: str
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cwd: str = ""
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timeout: float = DEFAULT_TIMEOUT
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max_bytes: int = DEFAULT_MAX_BYTES
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@dataclass(frozen=True)
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class ExecResult:
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"""What running it produced.
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`output` is stdout and stderr interleaved, because a shell transcript is
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what the model needs to read and separating them loses the ordering that
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makes an error make sense.
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"""
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exit_status: int
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output: str
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truncated: bool = False
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timed_out: bool = False
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duration_ms: int = 0
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@property
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def ok(self) -> bool:
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return self.exit_status == 0 and not self.timed_out
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class ExecError(Exception):
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"""Nothing could be run at all: the host refused, or the credential did.
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Distinct from a command that ran and failed -- that is an `ExecResult` with
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a non-zero status, which the model should read and react to. This is the
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reply not being able to act, which is a message for a person.
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"""
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def __init__(self, message: str) -> None:
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super().__init__(message)
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self.message = message
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@dataclass(frozen=True)
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class Target:
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"""A machine an agent chat acts on, read while the session was open.
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Holds the decrypted credential and nothing else does. `generation` clears it
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when the reply ends, because a finished `Generation` lingers for five
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minutes so late followers get the final frames, and a private key should not
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linger with it.
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"""
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kind: str
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label: str
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project_dir: str = ""
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spec: dict[str, Any] = field(default_factory=dict)
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class Executor(Protocol):
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"""How a target is acted on. See `ssh.py`; there is no local variant."""
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async def run(self, request: ExecRequest) -> ExecResult: ...
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async def read_file(self, path: str, *, max_bytes: int) -> str: ...
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async def write_file(self, path: str, text: str) -> int: ...
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async def list_dir(self, path: str) -> list[str]: ...
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def clean_output(data: bytes | str, *, limit: int) -> tuple[str, bool]:
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"""Decode, strip escape sequences, and cap. Returns (text, truncated)."""
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text = data.decode("utf-8", "replace") if isinstance(data, bytes) else data
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text = _ANSI.sub("", text)
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if len(text) <= limit:
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return text, False
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return text[:limit].rstrip() + "\n… (truncated)", True
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__all__ = [
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"DEFAULT_MAX_BYTES",
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"DEFAULT_TIMEOUT",
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"ExecError",
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"ExecRequest",
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"ExecResult",
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"Executor",
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"Target",
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"clean_output",
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]
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