close_session

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

With no annotations, the description carries the full burden. It does disclose useful behavioral details about parameter resolution (e.g., 'will use SSH config or current user' and 'default 22'). However, it does not mention side effects of closing a session (e.g., impact on running processes) or how errors are handled if the host is not found. For a destructive operation, more behavioral context would be beneficial.

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 well-structured with a brief intro and an Args list. However, there is redundancy: the host explanation is repeated both in the prose and in the Args entry. This is a minor inefficiency, but the overall length is appropriate and front-loaded.

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?

For a relatively simple tool with 3 parameters and an output schema, the description covers the essential aspects: purpose, parameter semantics, and defaults. It lacks edge-case behavior such as behavior when the host does not match an existing session, but it does not need to explain return values since an output schema exists.

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%, but the description fully compensates by explaining each parameter with concrete meaning and defaults. It clarifies that host can be a hostname/IP or alias, username is optional and falls back to SSH config or current user, and port defaults to SSH config or 22. This adds significant value beyond the bare schema.

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 opens with a clear verb-resource pair: 'Close a specific SSH session.' It specifies the exact scope (specific vs all sessions) and distinguishes itself from close_all_sessions. The mention of 'SSH session' clearly identifies the resource being acted on.

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 context that this tool targets a single SSH session, implying it is for per-session management. However, it does not explicitly mention alternatives or when not to use it, such as 'use close_all_sessions to close multiple sessions at once.'

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