qemu_screenshot

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds genuinely useful behavior: it works headless via the VGA framebuffer, and it raises a clear error rather than an opaque decoding failure if the VM exits mid-capture. It does not say where the resulting image goes (returned inline vs. written to disk), which is the main remaining behavioral gap.

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 short sentences, front-loaded with the core action and output format, followed by usage cases and error behavior in descending priority. The parenthetical about error messaging is slightly verbose but still earns its place.

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?

With no output schema, the description could say more about the return value (image content vs. file path), but "Capture the VM's display as a PNG image" implies an image is returned. For a single-parameter read-only tool, the coverage of purpose, use cases, and failure mode is close to 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?

Schema coverage is 0%, so the description must carry the burden for the single "name" parameter — but it never mentions it. An agent can infer it identifies the target VM from the sibling qemu_* tools, but this is left to inference rather than stated.

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 states a specific verb and resource ("Capture the VM's display as a PNG image") and names the mechanism (QMP screendump), which distinguishes it from the adjacent qemu_serial / qemu_wait_screen tools. An agent can identify the tool's function without opening the schema.

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?

It gives concrete when-to-use cases: boot screens, kernel panics, GUIs, and a text console that doesn't write to serial. The serial-based alternative is implied but not named explicitly, and no when-not-to-use case is given, so it falls short of a 5.

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