Skip to main content
Glama
Sign In
SSH MCP Server

SSH MCP Server

by YawLabs
OverviewSchemaSourceRelated ServersDiscussionsAdmin
TypeScript
Local

ssh_multi_exec

Run one shell command across multiple remote hosts in parallel and get per-host results, replacing repeated single-host SSH calls.

Instructions

Execute a command on multiple remote hosts in parallel. Runs at most SSH_MCP_MAX_POOL_SIZE hosts at once (default 100) and works through a longer list as slots free up. timeout is per host: it bounds each host's command, not the whole call. Each parallel slot works through its share of the list one host at a time, so with the pool to itself a call can take up to about ceil(hosts / SSH_MCP_MAX_POOL_SIZE) x (timeout + connect time). The connection pool is shared with every other tool; when it is full this call waits for slots instead of failing, and gives up only when none of its own hosts holds a slot and a full timeout has passed with none of them starting or finishing. The hosts waiting at that point (up to one per parallel slot) and every host still queued then report Connection pool is full; the queued ones are never attempted. Rerun those hosts once the other calls finish, or raise SSH_MCP_MAX_POOL_SIZE. Returns results per host. Use this instead of calling ssh_exec multiple times — it's faster and shows results side by side. Use env to set environment variables for this call without modifying the command string. Subject to SSH_MCP_COMMAND_WHITELIST / SSH_MCP_COMMAND_BLACKLIST if configured (policy is checked once, against the env-prefixed command, before fan-out).

Input Schema

NameRequiredDescriptionDefault
envNoEnvironment variables to set for this command. Injected as a `KEY='value' ...` prefix; works on any sshd regardless of AcceptEnv config. VALUES are POSIX-single-quoted, so any byte is safe in a value. KEYS cannot be quoted (a shell assignment prefix requires a bare name), so each key must match /^[A-Za-z_][A-Za-z0-9_]*$/ (the POSIX name grammar) — a key outside that grammar is rejected and the call fails before anything is sent to a host. Command policy is checked against the PREFIXED command, so a `^`-anchored whitelist pattern stops matching once this is set.
portNoSSH port (default: 22)
hostsYesList of SSH hostnames or IPs
commandYesShell command to execute on all hosts
timeoutNoPer-host command timeout in milliseconds (default: 30000): bounds each host's command, not the whole call. Also the call's no-progress budget on a full pool (see the tool description).
passwordNoSSH password. STRONGLY prefer key-based auth (privateKeyPath or ssh-agent). Passwords pass through MCP protocol frames as plaintext and may be logged by the transport or host process.
usernameNoSSH username (default: current user)
privateKeyPathNoPath to SSH private key

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changedv0.18.1
    • addedInput schema / properties / hosts / minItems
      Added value: +1
  2. Changed2 schema fields changedv0.17.0
    • addedInput schema / properties / env
      Added value: +{
+  "additionalProperties": {
+    "type": "string"
+  },
+  "description": "Environment variables to set for this command. Injected as a `KEY='value' ...` prefix; works on any sshd regardless of AcceptEnv config. VALUES are POSIX-single-quoted, so any byte is safe in a value. KEYS cannot be quoted (a shell assignment prefix requires a bare name), so each key must match /^[A-Za-z_][A-Za-z0-9_]*$/ (the POSIX name grammar) — a key outside that grammar is rejected and the call fails before anything is sent to a host. Command policy is checked against the PREFIXED command, so a `^`-anchored whitelist pattern stops matching once this is set.",
+  "propertyNames": {
+    "type": "string"
+  },
+  "type": "object"
+}
    • changedInput schema / properties / timeout / description
      Previous value: -"Command timeout in milliseconds (default: 30000)"New value: +"Per-host command timeout in milliseconds (default: 30000): bounds each host's command, not the whole call. Also the call's no-progress budget on a full pool (see the tool description)."
  3. Addedv0.9.1

TDQS

A4.5/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With zero annotations, the description carries the full burden and does so thoroughly: it discloses the shared connection pool, queueing rather than failing, the exact no-progress give-up condition, which hosts get reported as 'Connection pool is full', and that whitelist/blacklist policy is evaluated once against the env-prefixed command before fan-out. These are non-obvious behaviors an agent could not infer from the schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The operation and its primary use case are front-loaded, and the dense middle is warranted by genuinely complex pool semantics. It is longer than ideal — the pool-exhaustion paragraph is a single hard-to-parse sentence — but almost every clause carries operational information rather than filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Concurrency, timeout, policy, and failure behavior are all covered for an 8-parameter tool with no annotations. The one gap is the return value: 'Returns results per host' does not say whether each entry carries exit status, stdout/stderr separation, or how failed hosts are represented, and there is no output schema to fall back on.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description reinforces the important `timeout` scoping (per host, not whole call) and the env-prefix interaction with `^`-anchored whitelists, but those details are already present in the schema, so it adds little beyond structured data.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb, resource, and concurrency mode ('Execute a command on multiple remote hosts in parallel') and explicitly distinguishes itself from the sibling ssh_exec by naming the alternative pattern to avoid. An agent can select this over ssh_exec without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives an explicit routing rule ('Use this instead of calling ssh_exec multiple times — it's faster and shows results side by side'), plus remedial guidance for the failure path (rerun the reported hosts or raise SSH_MCP_MAX_POOL_SIZE) and a note on when to prefer `env` over command-string manipulation.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

Other Tools