Retrieve datasource instances for a device using device ID and device-datasource ID. Enables monitoring specific metrics like CPU cores or disk volumes.
Get instances of a datasource on a device (resource)
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Max results | |
| device_id | Yes | Device ID | |
| device_datasource_id | Yes | Device-DataSource ID (from get_device_datasources) |
Changes observed during successful MCP inspections.
v4.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds minimal context beyond that; it doesn't mention pagination (despite a limit parameter) or clarify that it returns a list of instances. Since annotations cover safety, the description's contribution is limited but not contradictory.
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 extremely concise—a single sentence that clearly states the tool's purpose without unnecessary details. It is front-loaded with the verb and resource, making it easy to scan. No wasted words.
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 read-only listing tool with full schema coverage and no complex output schema, the description covers the core purpose adequately. It lacks explicit mention of pagination, but that is minor. The annotations already declare the safety profile. The tool has a 'limit' parameter, so mentioning pagination would be a nice addition, but it's not critical.
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%, so the schema already documents all parameters. The description references 'device_datasource_id' by name in the schema but adds no extra semantic meaning beyond what's stated. With full coverage, a baseline of 3 is appropriate; the description doesn't enhance understanding of 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 states a specific verb ('Get'), resource ('instances of a datasource on a device'), and names the resource type ('resource'). It is clear and distinguishes the tool from siblings like get_device_data (which fetches data) or get_device_datasources (which lists datasources). It is concise but does not explicitly differentiate from similar 'get' tools, hence not a 5.
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 implies usage for retrieving instances but does not provide explicit guidance on when to use this tool versus alternatives like get_device_data or get_datasource. The context is clear from the name and description, but there is no 'when not to use' or mention of alternative tools. It is adequate but not explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.