open_session

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

With no annotations, the description carries the burden of behavioral disclosure. It adds useful context by noting the session_id format and that the initial snapshot is included for verification. However, it does not disclose potential side effects such as tmux window lifecycle, failure handling, or required permissions.

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?

The description is concise and well-structured. It front-loads the primary action, then supplies necessary details in two short sentences. Every sentence adds value without 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?

The description covers the main purpose, return value, and connection verification, which is adequate for a straightforward tool. However, it omits details about optional parameters and potential caveats like connection failures or session cleanup. The presence of an output schema reduces the need to describe the response structure, but broader context remains incomplete.

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 0%, so the description must compensate for parameter meaning. It explains the 'host' parameter thoroughly (alias or hostname/IP), but provides no explanation for 'port' or 'username', leaving these parameters underspecified.

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 clearly states the tool's action and resource: 'Open a new SSH session in a tmux window.' It also specifies the return value (session_id) and distinguishes itself from sibling tools that list, close, or send commands to sessions.

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 provides clear usage context by explaining that the host can be an SSH config alias or hostname/IP and that the session_id format follows 'user@host-<id>'. It implies when to use the tool (to establish a new session), though it does not explicitly mention alternatives or exclusion cases.

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