Retrieve a specific key from a table in a PowerDesigner model by providing model, table, and key references. Returns key details for schema inspection or validation.
Get one key by ref (from list_keys).
| Name | Required | Description | Default |
|---|---|---|---|
| key_ref | Yes | ||
| model_id | Yes | ||
| table_ref | 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 provided, the description carries the full burden of behavioral disclosure, but it only says 'Get one key by ref'. It does not state whether this operation is read-only, what is returned, or how errors behave. The phrase 'from list_keys' is the only added behavioral context.
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, front-loaded sentence with no filler. Every word contributes meaning, and the key source hint 'from list_keys' is included without bloat. This is appropriately sized for the tool's simplicity.
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?
Given three required parameters, no output schema, and no annotations, this description covers only the source of key_ref and leaves the role of model_id and table_ref implied. It does not describe the return value, prerequisites, or relationship to sibling tools, so an agent would need external inference to invoke this confidently.
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 0%, so the description must compensate for all three parameters. It adds meaning only for key_ref via 'by ref (from list_keys)'; model_id and table_ref receive no explanatory meaning beyond their names. This is insufficient for an agent to confidently know the exact scope and format of each parameter.
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 verb ('Get') and resource ('one key'), with the precise selection mechanism 'by ref'. The parenthetical '(from list_keys)' adds useful context about where the ref comes from, though it does not fully contrast against sibling get_* siblings beyond that.
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 'from list_keys' implies the intended workflow: first call list_keys, then use get_key with a key_ref from that result. However, there is no explicit guidance on when to choose this tool over alternatives like get_index or get_reference, leaving usage mostly inferred.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.