Set device

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

Annotations indicate the tool is not read-only (readOnlyHint=false), not destructive (destructiveHint=false), and idempotent (idempotentHint=true). The description adds meaningful context by stating that the override is process-scoped and explaining the special 'auto' value to clear it. This goes beyond the annotations by clarifying the effect and scope of the operation without contradicting any hints.

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 two short sentences, with the main action stated first and the special case immediately after. Every word contributes value; there is no redundant information. This is a model of concise, well-structured documentation.

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 one-parameter setter with no output schema and annotations covering safety, the description is complete. It explains what the tool does, the scope (MCP process), and the special value 'auto'. There are no hidden behaviors or additional required context for a basic use case.

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 schema only defines 'serial' as a string with no description, providing 0% coverage. The description compensates by explaining the purpose of the parameter ('Override the active device serial') and the special value 'auto' that clears the override. While it does not enumerate all possible serial formats, it adds essential semantic meaning for the 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 clearly states the tool's action: 'Override the active device serial for this MCP process.' This specifies the verb (override), the resource (active device serial), and the scope (this MCP process). It also distinguishes itself from sibling tools that inspect or control devices by focusing on setting a process-wide context value.

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: you would use this tool to change the device context for subsequent commands within the MCP process. It provides a specific instruction for clearing the override ('Use "auto" to clear override'), but it does not explicitly state when to use this tool versus alternatives, nor does it mention any exclusions or prerequisites. The usage is inferred rather than clearly guided.

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