set_device

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

No annotations provided, so description carries full burden. It discloses that it emulates a device and conditionally sets User-Agent, but does not mention other potential side effects (e.g., viewport, timezone) or whether changes are reversible. Lacks detail on error behavior or 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?

Description is four lines with a clear first sentence stating purpose, followed by action-oriented instruction. No redundant words, efficient use of vertical space.

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 a single parameter and presence of an output schema, the description covers the core functionality, how to find valid inputs, and a key side effect. Lacks information on error states or what the tool returns, but output schema likely handles that. Overall adequate for the tool's simplicity.

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?

Only one parameter 'profile' with 0% schema coverage. Description adds meaning by explaining it is a preset device and directing to list_devices for valid keys, with examples like 'iphone-15-pro'. This compensates well, though a more explicit enumeration or format would improve it further.

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?

Description clearly states 'Emulate a preset device' and specifies the verb-resource relationship. It distinguishes from siblings like set_user_agent and set_viewport by focusing on device emulation as a whole, and provides concrete examples of profile keys.

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?

Explicitly instructs to call list_devices first to see available profiles, which is strong guidance. Also notes that User-Agent is set when the profile provides one. Could be improved by mentioning when to use this over alternative tools like set_user_agent, but current guidance is clear and useful.

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