Emulate device preset

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

The description discloses rich behavioral details beyond annotations: all signals are set together to avoid contradictions, ipad_air deliberately reports desktop-class Safari with touch and no client hints, emulation survives navigation, and passing `device` to new_page/navigate_page is required for first-request signals. This complements the idempotentHint and non-destructive annotations without contradiction.

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 well-structured and front-loaded: a one-sentence purpose, then usage justification, preset details, and scope/undo notes. Each sentence earns its place; no filler or redundancy.

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 tool with 5 params, an output schema, and good annotations, the description covers the key contextual aspects: what the preset includes, when to use an alternative, page-scope behavior, and how to undo. The remaining parameter semantics are fully handled by the schema, so nothing critical is missing.

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 coverage is 100% with detailed parameter descriptions, so the baseline is 3. The description adds value by explaining what 'internally consistent' means (why presets matter) and elaborating on the ipad_air preset's specific behavior, which aids parameter selection beyond the raw schema.

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 verb and resource: 'Emulate a phone or tablet with one internally consistent set of signals.' It clearly distinguishes itself from the sibling 'emulate' tool by emphasizing preset-based consistency and positioning itself as the preferred approach for mobile work.

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 states when to use this tool ('Preferred over assembling `emulate` parameters by hand for mobile work') and gives concrete alternatives: use `new_page` or `navigate_page` for first-request signals, and `reset_emulation` to undo. This offers clear decision guidance versus siblings.

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