print_textPrints plain text to a Memobird thermal printer via the device API. Use it to output short notes or receipts, noting text is sent as GBK so emoji and rare characters are dropped.
把一段纯文本打印到咕咕机。
文本按 GBK 编码发送，emoji 和部分生僻字会被静默丢弃。
| Name | Required | Description | Default |
|---|---|---|---|
| text | Yes | 要打印的文本内容 |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description has to carry the full weight of behavioral disclosure, and it delivers the most important trait: text is sent in GBK encoding, and emoji and some rare characters are silently dropped. That silent-loss warning is exactly the kind of context an agent cannot get from the schema, though the description says nothing about device availability or failure behavior for non-encodable input.
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 with zero filler: the action is stated first, and the encoding caveat follows immediately. Every sentence 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?
For a simple one-parameter print tool with an existing output schema, the definition covers the key behavioral risk: losing characters under GBK. Return values need not be explained because the output schema handles them, though device-state or delivery details are absent.
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 100%, so the schema already defines the single text parameter; however, the description adds real meaning beyond it by constraining what the text may safely contain. The GBK encoding constraint lets an agent know that some strings will be truncated or dropped when printed.
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 action (print a piece of plain text) and a specific target (the Gugu machine), and the word for plain text ('纯文本') implicitly separates this tool from the image, URL, and mixed-content siblings. It does not explicitly name those siblings, so the differentiation needs to be inferred from the noun phrase, not read directly.
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 gives no explicit statement of when to choose this tool over print_image, print_url, or print_mixed. The intended usage can only be inferred from the phrase '纯文本', so an agent must infer the alternative-selection rule instead of being told it.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.