canvas_status

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorldHint=false, so the safety profile is fully covered by structured data. The description's contribution is the workflow cue to call it once upfront before mutating operations; it adds no further behavioral detail (no cost, latency, or failure-mode context), so a baseline 3 is appropriate.

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?

A single dense sentence that front-loads the capability list and ends with the actionable timing instruction. Every clause carries information; there is no filler or repetition of the tool name.

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 an output schema present, return fields need not be explained, and the description still previews them; annotations cover safety. The only minor gap is what to do with the port value on a follow-up call, which is deferred to the parameter description rather than the tool description.

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%, and the port parameter's own description already explains its disambiguation role ('同时开着多个画布时...' referencing 可选画布 from a prior return). The tool description merely lists 端口 as something reported and adds no syntax or selection semantics beyond the schema, so the baseline 3 stands.

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+resource (查看画布状态) and enumerates exactly what is inspected: running state, which program variant (无限画布/内部版), port, version compatibility, project count. No sibling tool does anything similar, so the agent can distinguish it immediately from the project/node-creation siblings.

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 explicit timing guidance: '开始操作前先调一次' (call once before starting operations), which tells the agent precisely when this belongs in a workflow. It does not state when NOT to use it or name an alternative, but for a single status tool there is no real alternative to route against.

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