clear_canvas

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

No annotations are provided, so the description carries the burden. It clearly states the core effect — clearing the tablet canvas — but does not disclose whether the action is irreversible, whether unsaved content is lost, or whether saved sessions/snapshots are affected. That residual ambiguity keeps this below a 4.

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 short, front-loaded with the action, and includes concrete trigger examples. The unexplained '【递纸】' prefix adds a small amount of noise, but the operational content is still minimal and scannable.

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 zero-parameter, no-output-schema tool, the description covers the essential 'what' and 'when'. It is missing side-effect context such as irreversibility or whether saved snapshots are preserved, but these are not strictly required to invoke the tool correctly.

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 and the input schema is empty, so there are no parameter semantics to add. The baseline for 0-parameter tools is 4, and the description does not need to compensate for any schema gaps.

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 gives a specific verb and object: 'Clear the tablet canvas', which is unambiguous and immediately distinguishable from the sibling tools (get_handwriting, save_snapshot, export_session, etc.). The included trigger phrases reinforce the exact intent.

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 states when to call the tool: when the user says '清空画布', 'clear', or '重新开始'. It does not name alternatives or exclusions, but for a zero-parameter clear action the trigger-based guidance is clear and sufficient.

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