Wait until the screen changes

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

With no annotations, the description carries the full burden. It usefully discloses the blocking/synchronous nature, the timeout escape hatch, and that a screenshot is returned, but omits failure modes (error vs. current screen on timeout), any session/KVM connection prerequisite, and whether the returned image is pre- or post-change.

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 with the core behavior front-loaded and the usage guidance second; no filler.

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 two-optional-parameter, no-annotation, no-output-schema tool, the description covers the essential contract: it blocks, it can time out, and it returns a screenshot. Only edge-case behavior on timeout and connection prerequisites are left implicit.

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%, so the schema already documents both parameters and their defaults, giving a baseline of 3. The description mentions 'timeout' in passing but adds no meaning for min_changed_fraction or tuning guidance for either parameter.

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 and resource ('Blocks until the host screen changes noticeably') plus the outcome ('then returns a screenshot'), which cleanly differentiates it from the sibling 'screenshot' tool that presumably returns immediately.

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?

Gives concrete usage context: 'Use after actions that take time (boot, install steps, page loads).' Clear positive guidance, but no explicit exclusions or named alternative (e.g., 'use screenshot instead if the screen is already stable').

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