pty-mcp

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the action ('Open') but doesn't explain what happens after opening (e.g., session persistence, resource consumption, or interaction methods). It lacks details on permissions, error handling, or whether this creates a persistent connection, leaving significant gaps for a tool that likely involves system resources.

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 a single, direct sentence with zero wasted words. It front-loads the core action and resource, making it immediately clear. Every word earns its place, and there's no redundancy or unnecessary elaboration, achieving optimal conciseness.

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 the complexity of opening a serial session (involving system resources and potential side effects), the description is inadequate. No annotations exist to cover behavioral traits, and there's no output schema to explain return values. The description doesn't address what the tool returns (e.g., a session ID), error conditions, or how to interact with the session post-creation, leaving critical gaps for effective use.

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 100%, with clear documentation for both parameters (baud_rate and device), including defaults and examples. The description adds no additional parameter information beyond what the schema provides, such as valid baud rate ranges or device path conventions. This meets the baseline for high schema coverage but doesn't enhance understanding.

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 ('Open') and resource ('a serial port session'), making the purpose immediately understandable. It distinguishes from siblings like 'create_local_session' and 'create_ssh_session' by specifying 'serial port', though it doesn't explicitly contrast with them. The purpose is specific but could be more differentiated.

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 no guidance on when to use this tool versus alternatives like 'create_local_session' or 'create_ssh_session'. It doesn't mention prerequisites, such as needing an available serial device, or when this tool is appropriate compared to other session creation methods. Usage is implied but not articulated.

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