pty-mcp

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the action ('Send') but doesn't clarify effects (e.g., whether it's destructive, how it interacts with sessions, or any rate limits). For a tool that likely modifies session state, this lack of detail is a significant gap, though it doesn't contradict any annotations.

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, efficient sentence with zero waste. It front-loads the core purpose and includes helpful examples without unnecessary elaboration. Every word earns its place, making it easy for an agent to parse quickly.

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 (a session control tool with 2 parameters), no annotations, and no output schema, the description is incomplete. It lacks details on behavioral traits, parameter usage, and expected outcomes, which are critical for safe and effective invocation. The conciseness comes at the cost of necessary context.

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 undocumented parameters. It mentions 'key' with examples but doesn't explain the 'session_id' parameter or provide format details (e.g., valid key values, session ID sourcing). This adds minimal value beyond the schema's property names, failing to fully address the coverage gap.

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 ('Send') and target ('a control key'), with specific examples provided (ctrl+c, ctrl+d, etc.). It distinguishes itself from sibling tools like 'send_input' by focusing on control keys rather than general input. However, it doesn't explicitly mention the session context, which is implied by the parameter but could be more specific.

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?

No explicit guidance is provided on when to use this tool versus alternatives like 'send_input' or other session-related tools. The description implies usage for control keys but doesn't specify scenarios (e.g., interrupting processes, navigating interfaces) or prerequisites (e.g., requiring an active session). This leaves the agent to infer context from parameters alone.

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