canvas_preview

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

With no annotations, the description must carry the burden. The word 'preview' strongly implies a read-only operation, and the phrase 'same as canvas_export' adds behavioral context if that tool is known. However, it doesn't explicitly state that it makes no changes, nor describe the output or any side effects, leaving some ambiguity.

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, compact sentence that immediately states the core purpose and usage context. It is front-loaded and contains no filler, making it highly efficient.

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 tool with no parameters, no output schema, and a simple preview function, the description is largely complete. It explains the purpose and when to use it (intermediate checks). The only minor gap is that it doesn't describe the output format, but given the simplicity, this is not critical.

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?

The tool has zero parameters, so the baseline is 4. The description correctly omits any parameter details since none exist. No additional semantic explanation is needed.

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 function: '预览当前画布状态' (preview the current canvas state), using a specific verb 'preview' and a clear resource. However, it references being 'same as canvas_export,' which introduces slight ambiguity about tool distinction, though it still conveys the core purpose.

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 explicitly says it is used for intermediate checks ('用于中间检查'), which gives clear context on when to use this tool. It doesn't explicitly list exclusions or alternatives, but it does reference canvas_export as the same tool, implying usage context. This is clear but not exhaustive.

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