List a directory on one of your servers over SFTP. Returns each entry's name, whether it's a directory, size and modified time. Runs keyless over Termalin's tunnel, like ssh_exec.
| Name | Required | Description | Default |
|---|---|---|---|
| host | Yes | Server id from hosts_list | |
| path | No | Directory to list (default the login home, ".") | |
| username | No | Login user (defaults to the tunnel's user, else root) |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the safety profile (readOnly, idempotent, non-destructive, openWorld). The description adds genuinely new behavioral context: it is keyless over the Termalin tunnel and shares the ssh_exec auth model, plus it enumerates the returned fields. What it omits is pagination or behavior on missing paths.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three tight sentences, front-loaded with the action and resource, then return shape, then execution model. No filler or redundancy.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema present, the description compensates by enumerating the returned entry fields (name, is-directory, size, modified time) and explaining the credential model. An agent has everything needed to invoke it correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so host, path, and username semantics (including defaults) are already fully documented in the schema. The description adds no parameter-level detail beyond that, making the baseline 3 correct.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb (List), resource (a directory), and transport (over SFTP on one of your servers), which cleanly separates it from sftp_read/sftp_write file operations. It does not explicitly name a sibling to route against, so it falls short of the top score.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Usage is implied by the verb and by the trailing comparison to ssh_exec, but there is no explicit when-to-use statement, no exclusion of sftp_read for single files, and no guidance on choosing between hosts_list and this tool. Adequate but inferential.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
