vterm_spawn

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

With no annotations, the description carries the full burden and does disclose the key behavioral fact: this creates a real, user-visible window on their screen — an observable side effect an agent must not trigger casually. It also implies a lifecycle requiring vterm_close. It does not cover failure modes (e.g., headless/no interactive session) or whether the window steals focus, keeping it below a 5.

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?

Two tight sentences: the first defines the action and its visible-window nature, the second gives the return value and the follow-up tools. No filler, and the most decision-relevant fact (a visible window appears) is 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 one-optional-parameter spawn tool with no output schema, the description supplies the birth-to-death lifecycle (spawn → send/read → close) and explicitly states the pid return, which substitutes for the missing output schema. Minor gap: no note on environment prerequisites or whether multiple windows are permitted.

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% and the single optional cwd parameter is fully documented in the schema, so baseline 3 applies. The description adds no information about cwd semantics (e.g., whether it must exist or how paths are resolved) beyond what the schema already says.

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?

States a specific verb (open/spawn) and resource (a PowerShell console window) plus the distinguishing trait that it is 'genuinely visible' to the user, which separates it from any hypothetical headless execution. It also declares the return value (pid) and maps it to the sibling tools that consume it.

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 clearly establishes the workflow: spawn first, then use the returned pid with vterm_send / vterm_read / vterm_close, naming all three siblings. It stops short of explicit when-not guidance (e.g., when to reuse an existing session rather than spawn a new window), so it is clear context without exclusions.

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