SSH connections, kept by the people who own them

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>
This commit is contained in:
Jaroslav Beneš
2026-08-01 22:34:58 +02:00
parent c3d6660881
commit fe7227af62
21 changed files with 2452 additions and 7 deletions
+6
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@@ -471,3 +471,9 @@ a.tabs__tab { text-decoration: none; }
background: var(--code-bg);
border: 1px solid var(--code-border);
}
/* --- The permission modes, explained on the agents page ------------------- */
.mode-list { margin: 0; display: flex; flex-direction: column; gap: var(--sp-2); }
.mode-list__row { display: flex; gap: var(--sp-3); align-items: baseline; }
.mode-list__row dt { flex: 0 0 5rem; color: var(--ink); }
.mode-list__row dd { margin: 0; color: var(--ink-muted); font-size: var(--text-sm); }
+4 -7
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@@ -47,6 +47,10 @@
{{ icon("link", "icon--sm") }}
<span class="nav-item__label">Tools</span>
</a>
<a class="nav-item {{ 'is-active' if section == 'agents' }}" href="/admin/agents">
{{ icon("sparkle", "icon--sm") }}
<span class="nav-item__label">Agents</span>
</a>
<a class="nav-item {{ 'is-active' if section == 'mcp' }}" href="/admin/mcp">
{{ icon("server", "icon--sm") }}
<span class="nav-item__label">MCP servers</span>
@@ -70,13 +74,6 @@
</a>
</div>
<div class="nav-group">
<div class="nav-group__label">Not yet built</div>
<span class="nav-item is-disabled">
{{ icon("server", "icon--sm") }}
<span class="nav-item__label">Agents</span>
</span>
</div>
</nav>
<div class="sidebar__footer">
+184
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@@ -0,0 +1,184 @@
{% extends "admin/_layout.html" %}
{% from "_macros.html" import icon %}
{% set section = "agents" %}
{% block title %}Agents - LLeMbas{% endblock %}
{% block heading %}Agents{% endblock %}
{% block admin_content %}
<p class="admin-lede">
An <strong>Agent</strong> chat can read files, write files and run commands on
a machine reached over SSH. Nothing runs on this server. People add their own
connections under <strong>Connections</strong>; what you decide here is
whether the feature exists and what one reply may spend.
</p>
<div class="alert">
{{ icon("shield", "icon--sm") }}
<span>
There is no sandbox to configure, and that is deliberate: containment is
whatever host somebody points a connection at. A container built for the
job is a very different thing from a key to a live server, and LLeMbas
cannot tell them apart. What a model reads — a web page, a file, the output
of the last command — is untrusted, and in <strong>Auto</strong> mode
nothing stands between that and a command running.
</span>
</div>
{% if problem %}
<div class="alert alert--error">{{ icon("warning", "icon--sm") }} <span>{{ problem }}</span></div>
{% endif %}
{% if saved %}
<div class="alert alert--success">{{ icon("check", "icon--sm") }} <span>Saved.</span></div>
{% endif %}
<form method="post" action="/admin/agents" class="form-grid">
<section class="card">
<h2 class="card__title">Switch</h2>
<div class="field">
<label class="checkbox">
<input type="checkbox" name="enabled" value="true" {{ 'checked' if values.enabled }}>
<span>Allow agent chats</span>
</label>
<p class="field__hint">
Off, nobody can start one and no agent tool is offered, whatever
permissions they hold. {{ profile_count }} connection{{ '' if profile_count == 1 else 's' }}
saved across all accounts.
</p>
</div>
<p class="field__hint">
People also need the <strong>Run commands</strong> permission, a model
flagged <strong>Agent execution</strong>, and a connection of their own.
</p>
</section>
<section class="card">
<h2 class="card__title">The modes</h2>
<p class="field__hint">
Set per chat and switchable at any time. This is what each one means; the
two lists below adjust them.
</p>
<dl class="mode-list">
{% for value, label, hint in modes %}
<div class="mode-list__row">
<dt><strong>{{ label }}</strong></dt>
<dd>{{ hint }}</dd>
</div>
{% endfor %}
</dl>
</section>
<section class="card">
<h2 class="card__title">What never needs asking</h2>
<div class="field">
<label class="field__label" for="allow_default">Always allow</label>
<textarea class="textarea input--mono" id="allow_default" name="allow_default" rows="5"
spellcheck="false">{{ allow_text }}</textarea>
<p class="field__hint">
One per line: a tool name like <code>file_read</code>, or a command with
wildcards like <code>git *</code>. A command containing anything that
joins two commands together — a semicolon, a pipe, backticks — can never
match one of these, so <code>git *</code> does not quietly also mean
<code>git status; curl … | sh</code>.
</p>
</div>
</section>
<section class="card">
<h2 class="card__title">What always needs asking</h2>
<div class="field">
<label class="field__label" for="deny_default">Always ask</label>
<textarea class="textarea input--mono" id="deny_default" name="deny_default" rows="5"
spellcheck="false">{{ deny_text }}</textarea>
<p class="field__hint">
Checked before everything, including <strong>Auto</strong>. Treat it as
a guard against an accident rather than against an adversary:
<code>rm -rf /*</code> here does not stop <code>/bin/rm -rf /</code>, and
nothing pattern-shaped could.
</p>
</div>
</section>
<section class="card">
<h2 class="card__title">What one command may spend</h2>
<div class="field">
<label class="field__label" for="default_timeout">Timeout (seconds)</label>
<input class="input" id="default_timeout" name="default_timeout"
value="{{ values.default_timeout }}" inputmode="numeric">
</div>
<div class="field">
<label class="field__label" for="max_timeout">Longest a command may ask for</label>
<input class="input" id="max_timeout" name="max_timeout"
value="{{ values.max_timeout }}" inputmode="numeric">
</div>
<div class="field">
<label class="field__label" for="max_output_bytes">Most output to keep</label>
<input class="input" id="max_output_bytes" name="max_output_bytes"
value="{{ values.max_output_bytes }}" inputmode="numeric">
<p class="field__hint">
Characters. The rest is cut off and the model is told so.
</p>
</div>
</section>
<section class="card">
<h2 class="card__title">What one reply may spend</h2>
<p class="field__hint">
Three separate bounds, because they fail differently: steps stop a loop,
the clock stops one slow command eating an afternoon, and output stops a
model filling its own context with build logs and having no room to answer.
</p>
<div class="field">
<label class="field__label" for="max_steps">Most rounds of tool calls</label>
<input class="input" id="max_steps" name="max_steps"
value="{{ values.max_steps }}" inputmode="numeric">
</div>
<div class="field">
<label class="field__label" for="max_wall_seconds">Longest a reply may take</label>
<input class="input" id="max_wall_seconds" name="max_wall_seconds"
value="{{ values.max_wall_seconds }}" inputmode="numeric">
<p class="field__hint">Time spent waiting for you to answer does not count.</p>
</div>
<div class="field">
<label class="field__label" for="max_total_output_bytes">Most output across a reply</label>
<input class="input" id="max_total_output_bytes" name="max_total_output_bytes"
value="{{ values.max_total_output_bytes }}" inputmode="numeric">
</div>
</section>
<section class="card">
<h2 class="card__title">Asking you things</h2>
<div class="field">
<label class="field__label" for="approval_timeout">How long a question waits</label>
<input class="input" id="approval_timeout" name="approval_timeout"
value="{{ values.approval_timeout }}" inputmode="numeric">
<p class="field__hint">
Seconds. After this the reply carries on without an answer and says so.
At least a minute, whatever is typed here.
</p>
</div>
<div class="field">
<label class="checkbox">
<input type="checkbox" name="ask_free_text" value="true"
{{ 'checked' if values.ask_free_text }}>
<span>Let people write their own answer</span>
</label>
<p class="field__hint">
When a model asks a question it can offer answers to pick from, and by
default a box to write something else. Turn this off if you would rather
nobody typed free text into a prompt a model composed.
</p>
</div>
</section>
<div class="btn-row">
<button class="btn btn--primary" type="submit">Save changes</button>
</div>
</form>
{% endblock %}
@@ -0,0 +1,72 @@
{% from "_macros.html" import icon %}
{#
What looking at a host found.
Everything here came from the far side and is escaped accordingly. The
fingerprint especially: it is the one string a person is being asked to
compare against something they know, so it is shown plainly and never
reformatted.
#}
{% if error %}
<div class="alert alert--error">{{ icon("warning", "icon--sm") }} <span>{{ error }}</span></div>
{% endif %}
{% if offer %}
<div class="card" style="margin-top: var(--sp-4)">
<h3 class="card__title">
{{ "This host's key has changed" if offer.changed else "Is this the machine you meant?" }}
</h3>
<p class="field__hint">
{% if offer.changed %}
Accept only if you know why it changed — a rebuilt container will do this,
and so will something pretending to be your machine.
{% else %}
Compare this with what the host reports for itself. On the machine, that
is <code>ssh-keygen -lf /etc/ssh/ssh_host_ed25519_key.pub</code>.
{% endif %}
</p>
<pre class="tool-result__text">{{ offer.fingerprint }}</pre>
<div class="btn-row">
<button class="btn btn--primary" type="button"
hx-post="/api/agents/{{ profile.id }}/accept"
hx-target="#check-result"
hx-confirm="Accept this fingerprint and pin it? Every future connection will be checked against it."
data-confirm-label="Accept"
data-confirm-danger="{{ 'true' if offer.changed else 'false' }}">
{{ icon("check", "icon--sm") }} Accept and pin
</button>
{% if profile.verified %}
<button class="btn" type="button"
hx-post="/api/agents/{{ profile.id }}/forget"
hx-target="#check-result">
Forget the old key
</button>
{% endif %}
</div>
</div>
{% endif %}
{% if accepted %}
<div class="alert alert--success">
{{ icon("check", "icon--sm") }}
<span>Pinned <code>{{ accepted }}</code>. Check again to log in.</span>
</div>
{% endif %}
{% if forgotten %}
<div class="alert">
{{ icon("warning", "icon--sm") }}
<span>Key forgotten. Check again to see the new one.</span>
</div>
{% endif %}
{% if found %}
<div class="alert alert--success">
{{ icon("check", "icon--sm") }}
<span>Connected{% if found.system %} to {{ found.system }}{% endif %}.</span>
</div>
<p class="field__hint">What it said:</p>
<pre class="tool-result__text">{{ found.output }}</pre>
{% endif %}
@@ -0,0 +1,35 @@
{% extends "base.html" %}
{% from "_macros.html" import icon %}
{#
Connections, kept by the person who owns them.
Shares the chat sidebar with the library for the same reason: this is part of
using LLeMbas, not administering it. You come here to add a machine and go
straight back to a conversation.
#}
{% block head %}
<link rel="stylesheet" href="{{ url_for('static', path='css/chat.css') }}">
<link rel="stylesheet" href="{{ url_for('static', path='css/admin.css') }}">
{% endblock %}
{% block body_attrs %} data-authenticated="true"{% endblock %}
{% block body %}
<div class="shell">
{% include "partials/sidebar.html" %}
<main class="main">
<header class="topbar">
<h1 class="topbar__title">{% block heading %}Connections{% endblock %}</h1>
<div class="topbar__actions">{% block actions %}{% endblock %}</div>
</header>
<div class="admin-scroll">
<div class="admin-page">
{% block agents_content %}{% endblock %}
</div>
</div>
</main>
</div>
{% endblock %}
+183
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@@ -0,0 +1,183 @@
{% extends "agents/_layout.html" %}
{% from "_macros.html" import icon %}
{% block title %}{{ "New connection" if is_new else profile.name }} - LLeMbas{% endblock %}
{% block heading %}{{ "New connection" if is_new else profile.name }}{% endblock %}
{% block agents_content %}
<nav class="crumbs">
<a class="crumbs__back" href="/agents">
{{ icon("chevron-right", "icon--sm crumbs__icon") }} All connections
</a>
</nav>
{% if error %}
<div class="alert alert--error">{{ icon("warning", "icon--sm") }} <span>{{ error }}</span></div>
{% endif %}
{% if problem %}
<div class="alert alert--error">{{ icon("warning", "icon--sm") }} <span>{{ problem }}</span></div>
{% endif %}
{% if saved %}
<div class="alert alert--success">{{ icon("check", "icon--sm") }} <span>{{ saved }}</span></div>
{% endif %}
{% if not is_new %}
<section class="card">
<h2 class="card__title">Check it</h2>
<p class="field__hint">
{% if profile.verified %}
Confirms the host is still the one you accepted, then logs in and runs
something harmless to see that it works.
{% else %}
Looks at this host's key and shows you its fingerprint. Nothing is sent to
it — not your username, not your credential — until you accept.
{% endif %}
</p>
<div class="btn-row">
<button class="btn" type="button"
hx-post="/api/agents/{{ profile.id }}/check"
hx-target="#check-result">
{{ icon("refresh", "icon--sm") }} Check
</button>
</div>
<div id="check-result">
{% if profile.verified %}
<p class="field__hint">
Accepted fingerprint: <code>{{ profile.host_fingerprint }}</code>
</p>
{% endif %}
</div>
</section>
{% endif %}
<form method="post" class="form-grid"
action="{{ '/api/agents' if is_new else '/api/agents/' ~ profile.id }}">
<section class="card">
<h2 class="card__title">The machine</h2>
<div class="field">
<label class="field__label" for="name">Name</label>
<input class="input" id="name" name="name" value="{{ profile.name }}" required
maxlength="120" placeholder="Project container">
<p class="field__hint">What you will pick from when starting an agent chat.</p>
</div>
<div class="field">
<label class="field__label" for="host">Host</label>
<input class="input input--mono" id="host" name="host" value="{{ profile.host }}" required
maxlength="255" placeholder="127.0.0.1">
</div>
<div class="field">
<label class="field__label" for="port">Port</label>
<input class="input" id="port" name="port" value="{{ profile.port }}" inputmode="numeric">
</div>
<div class="field">
<label class="field__label" for="username">Log in as</label>
<input class="input input--mono" id="username" name="username" required
value="{{ profile.username }}" maxlength="120" placeholder="root">
</div>
<div class="field">
<label class="field__label" for="default_dir">Project directory</label>
<input class="input input--mono" id="default_dir" name="default_dir"
value="{{ profile.default_dir }}" maxlength="500" placeholder="/project">
<p class="field__hint">
Where a chat starts by default. Each chat records its own when it is
created, so changing this later does not move a conversation already
under way.
</p>
</div>
<div class="field">
<label class="field__label" for="connect_timeout">Connect timeout (seconds)</label>
<input class="input" id="connect_timeout" name="connect_timeout"
value="{{ profile.connect_timeout }}" inputmode="numeric">
</div>
</section>
<section class="card">
<h2 class="card__title">How it logs in</h2>
<div class="field">
<div class="checkbox-row">
<label class="checkbox">
<input type="radio" name="auth" value="key"
{{ 'checked' if profile.auth != 'password' }}>
<span>A private key</span>
</label>
<label class="checkbox">
<input type="radio" name="auth" value="password"
{{ 'checked' if profile.auth == 'password' }}>
<span>A password</span>
</label>
</div>
</div>
<div class="field">
<label class="field__label" for="private_key">Private key</label>
<textarea class="textarea input--mono" id="private_key" name="private_key" rows="5"
spellcheck="false"
placeholder="-----BEGIN OPENSSH PRIVATE KEY-----"
>{{ unchanged if has_key else '' }}</textarea>
<p class="field__hint">
{% if has_key %}
A key is saved. Leave the dots alone to keep it, or clear the box to
remove it.
{% else %}
Pasted whole, encrypted at rest, and never shown again.
{% endif %}
</p>
</div>
<div class="field">
<label class="field__label" for="key_passphrase">Key passphrase</label>
<input class="input input--mono" id="key_passphrase" name="key_passphrase"
type="password" autocomplete="off" placeholder="If the key has one">
</div>
<div class="field">
<label class="field__label" for="password">Password</label>
<input class="input input--mono" id="password" name="password" type="password"
autocomplete="off" placeholder="No password set"
value="{{ unchanged if profile.password_encrypted else '' }}">
<p class="field__hint">
{% if profile.password_encrypted %}
Currently <code>{{ masked_password }}</code>. Leave the dots alone to
keep it, or clear the field to remove it.
{% else %}
Only used when this connection logs in with a password.
{% endif %}
</p>
</div>
</section>
<section class="card">
<h2 class="card__title">Availability</h2>
<div class="field">
<label class="checkbox">
<input type="checkbox" name="enabled" value="true" {{ 'checked' if profile.enabled }}>
<span>Enabled — can be picked when starting an agent chat</span>
</label>
</div>
</section>
<div class="btn-row">
<button class="btn btn--primary" type="submit">
{{ "Add connection" if is_new else "Save changes" }}
</button>
<a class="btn btn--ghost" href="/agents">Back to all connections</a>
{% if not is_new %}
<button class="btn btn--danger" type="submit" formnovalidate
formaction="/api/agents/{{ profile.id }}/delete"
data-confirm-button="Delete the connection “{{ profile.name }}”? Chats that used it keep their transcripts.">
Delete
</button>
{% endif %}
</div>
</form>
{% endblock %}
@@ -0,0 +1,94 @@
{% extends "agents/_layout.html" %}
{% from "_macros.html" import icon %}
{% block title %}Connections - LLeMbas{% endblock %}
{% block heading %}Connections{% endblock %}
{% block actions %}
<a class="btn btn--primary btn--sm" href="/agents/new">
{{ icon("plus", "icon--sm") }} Add a connection
</a>
{% endblock %}
{% block agents_content %}
<p class="admin-lede">
Machines an <strong>Agent</strong> chat can work on. A model with one of these
can read files, write files and run commands <em>there</em> — never here.
Which of those it may do without asking you first is the chat's mode.
</p>
<div class="alert">
{{ icon("shield", "icon--sm") }}
<span>
Whatever this connection can reach, a model in an agent chat can reach. A
container built for the job, with one project mounted into it, is a very
different thing from a key to a machine you care about — and LLeMbas cannot
tell them apart.
</span>
</div>
{% if problem %}
<div class="alert alert--error">
{{ icon("warning", "icon--sm") }} <span>{{ problem }}</span>
</div>
{% elif not enabled %}
<div class="alert alert--error">
{{ icon("warning", "icon--sm") }}
<span>
Agent chats are switched off for this instance. You can still add
connections here, but nothing will use them until an administrator turns
them on.
</span>
</div>
{% endif %}
{% if saved %}
<div class="alert alert--success">{{ icon("check", "icon--sm") }} <span>{{ saved }}</span></div>
{% endif %}
{% if not profiles %}
<div class="empty">
{{ icon("server", "empty__mark") }}
<h2 class="empty__title">No connections yet</h2>
<p class="empty__text">
Add the host, the user to log in as, and a key or password. Then press
<strong>Check</strong> — you will be shown its fingerprint to confirm before
anything is sent to it.
</p>
<a class="btn btn--primary" href="/agents/new">
{{ icon("plus", "icon--sm") }} Add a connection
</a>
</div>
{% else %}
<div class="model-rows">
{% for profile in profiles %}
<div class="model-row {{ 'is-off' if not profile.enabled }}">
<div class="model-row__main">
<div class="model-row__title">
<a class="model-row__name" href="/agents/{{ profile.id }}">{{ profile.name }}</a>
{% if profile.verified %}
<span class="badge badge--leaf">key confirmed</span>
{% else %}
<span class="badge badge--danger">not checked</span>
{% endif %}
{% if not profile.enabled %}<span class="badge">disabled</span>{% endif %}
{% if profile.auth == "password" %}<span class="badge">password</span>{% endif %}
</div>
<code class="model-row__id">
{{ profile.address }}{% if profile.default_dir %} · {{ profile.default_dir }}{% endif %}
</code>
{% if profile.last_error %}
<p class="text-xs danger">{{ profile.last_error }}</p>
{% elif profile.server_info.system %}
<p class="text-xs faint">{{ profile.server_info.system }}</p>
{% endif %}
</div>
<div class="model-row__actions">
<a class="btn btn--sm" href="/agents/{{ profile.id }}">Open</a>
</div>
</div>
{% endfor %}
</div>
{% endif %}
{% endblock %}
@@ -77,6 +77,13 @@
</a>
{% endif %}
{% if can.get("agent.ssh") %}
<a class="nav-item" href="/agents">
{{ icon("server", "icon--sm") }}
<span class="nav-item__label">Connections</span>
</a>
{% endif %}
<a class="nav-item" href="/settings">
{{ icon("user", "icon--sm") }}
<span class="nav-item__label">{{ user.name }}</span>