session_get_variable

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states this is a read operation ('Get'), which is helpful, but doesn't mention important behavioral aspects like what happens if the variable doesn't exist, whether this requires specific permissions, or how the value is returned. The description provides minimal behavioral context beyond the basic action.

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 efficiently structured with a clear purpose statement followed by parameter explanations. Every sentence earns its place, and the information is front-loaded with the core functionality stated first. The Args section is well-organized and adds necessary detail 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?

Given that there's an output schema (which handles return values), 0% schema description coverage, and no annotations, the description does an adequate job. It covers the basic purpose and parameters but lacks behavioral details about error conditions, permissions, or what types of values might be returned. For a read operation with output schema, this is minimally complete.

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?

With 0% schema description coverage, the description compensates well by explaining both parameters: it defines 'variable' with an example ('session.name', 'session.path') and clarifies the optional nature of 'session_id' with usage guidance. This adds significant semantic value beyond the bare schema, though it could provide more examples of valid variable names.

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 action ('Get the value') and resource ('an iTerm2 session variable'), making the purpose immediately understandable. It doesn't explicitly differentiate from siblings like 'session_set_variable' beyond the verb difference, but the verb 'Get' versus 'Set' provides inherent distinction.

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 some usage context by explaining when to omit the session_id parameter ('Omit for the active session'), which helps with parameter decisions. However, it doesn't offer guidance on when to use this tool versus alternatives like 'session_list' or 'session_set_variable' for related operations.

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