screenshot_chat

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

The description thoroughly discloses rendering behavior: it starts from a given message_id, renders downward, prepends earlier messages if they fit, and cuts off later messages if they overflow. This transparency is high, especially with no annotations provided. There is no contradiction with 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 concise and well-structured. It opens with a clear one-line summary, followed by a detailed paragraph on rendering behavior, and a clean parameter list. Every sentence adds value, and the total length is appropriate for the tool's complexity.

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?

The description covers the tool's purpose, behavior, parameters, and output format sufficiently. Although there is no output schema, the description explicitly states it returns a base64-encoded PNG. It is comprehensive for a tool without annotations; however, it could mention any required authentication or permissions, which is a minor gap.

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?

With 0% schema description coverage, the description fully compensates by clearly explaining each parameter: 'target' as Group ID or friend QQ ID, 'message_id' as the starting message ID, and 'target_type' with default 'group' or 'private'. This adds significant meaning beyond the schema's title and type.

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 tool's purpose: 'Take a QQ-style screenshot of chat messages starting from a specific message.' It specifies the style (dark-mode, iPhone style) and the output format (base64 PNG). This distinctively sets it apart from any sibling tools, as no other tool offers screenshot functionality.

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 explains the rendering behavior and input parameters but does not provide explicit guidance on when to use this tool versus alternatives. However, since no sibling tool serves a similar function (screenshot), the lack of explicit 'when not to use' is less critical. The description gives sufficient context for an agent to infer appropriate usage.

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