screen_dump

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

No annotations exist, so the description carries the full behavioral burden. It does a good job disclosing the shape of the returned data, but it never mentions that output is truncated (the `limit` parameter defaults to 60 with a max of 200), which is critical behavior for a screen with many nodes, nor does it mention refresh/freshness semantics.

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?

Two tight sentences: the first front-loads what is returned, the second front-loads the operational rule. No filler, no repetition of the tool name.

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?

With no output schema, the description does the necessary work of enumerating the returned fields, which is exactly what an agent needs to parse a dump. The only meaningful gap is the unmentioned truncation/default limit behavior, which affects whether the agent sees the whole screen.

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 50%: `device` is documented in the schema, but `limit` has no description anywhere. The description never mentions `limit`, its default of 60, or that raising it returns more nodes, so it does not compensate for the coverage gap on the one parameter that governs completeness of the result.

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?

States a specific verb and resource ('Read the current screen') and enumerates exactly what is returned: text, content description, resource id, tap coordinates, clickable/scrollable flags. This cleanly separates it from the sibling 'screenshot' (image) and 'device_info' (device metadata).

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?

'Use this before tapping anything so you act on real element positions instead of guessing' gives a clear trigger condition and rationale. It stops short of explicitly contrasting with 'screenshot' or saying when a screenshot is preferable over a structured dump, so the alternative routing is only implied.

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