Store key-value string pairs as document-level metadata in Rhino, persisting them in the .3dm file. This provides a way to save custom data alongside the model.
Store a document-level key/value string (persists in the .3dm file).
Args:
key: Key name.
value: Value string.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | ||
| value | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. It does disclose that the value persists in the .3dm file and that the operation stores data, which is useful. However, it does not mention what happens when the key already exists (overwrite vs. error), whether a save is required, or any side effects beyond persistence.
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 compact and front-loaded: a one-sentence purpose statement followed by two one-line argument explanations. There is no filler, and every sentence contributes useful information.
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 two-string-parameter setter with an output schema, the description provides the essential purpose, persistence detail, and parameter roles. The only notable gap is overwrite behavior for an existing key, which is a minor omission for this kind of key/value operation.
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 Args section adds minimal semantic labels: 'key: Key name' and 'value: Value string'. These clarify the role of each parameter but largely restate the schema's string types and titles. With 0% schema description coverage, this is the only semantic guidance, and it is just barely sufficient for such simple parameters.
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 opens with a specific action and scope: 'Store a document-level key/value string'. It clearly identifies the resource (document-level key/value store) and even notes persistence in the .3dm file. This is unambiguous and distinguishable from object-level or user-text tools.
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 phrase 'document-level' implies when this tool is appropriate, distinguishing it implicitly from user-text or object-level tools. However, it never explicitly names alternatives like rhino_set_user_text or rhino_get_document_text, so the agent must infer the when-not-to-use guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.