Start visible Windows Telnet

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

Annotations already flag readOnlyHint=false and openWorldHint=true, so the agent knows this is an actuating, externally-facing operation. The description adds genuinely useful behavioral context beyond the annotations: it opens a real, user-visible conhost.exe window and uses the built-in telnet.exe, which has visible UI side effects. It does not mention whether the call blocks or returns a session handle, but the visible-window and outbound-connection details are meaningful.

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?

Two efficient sentences with no filler. The first sentence front-loads the essential visible-window behavior, and the second adds the only conditional behavior worth calling out. It earns full credit for structure even though other dimensions have gaps.

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?

Given 8 parameters, no output schema, and an open-world annotation, the description is not complete enough for confident invocation. It explains host handling but leaves credentials-related fields (username/autoLogin), port defaults, terminalType, escapeCharacter, and logFile mostly unexplained, several of which also lack schema descriptions. The agent is also left guessing about return behavior and session lifecycle.

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 description coverage is only 25%, with six of eight parameters undecorated. The description mostly restates the host behavior already present in the schema and does not explain port defaults, the meaning of autoLogin, terminalType choices, escapeCharacter semantics, or title/logFile behavior. With low schema coverage, the description needed to compensate but largely does not.

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?

The description states a specific verb ('Opens') and resource ('conhost.exe window running the built-in Windows telnet.exe'), making the tool's action unmistakable. It also reveals the host-dependent outbound connection behavior, which clearly separates it from the sibling control/interaction tools.

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?

The description gives conditional usage context: provide a host to connect, omit it to get the Telnet prompt. However, it never explicitly explains when to choose this tool over telnet_send, telnet_focus, telnet_close, or the other siblings, nor does it mention prerequisites like the Windows Telnet client being enabled.

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