shield_screenshot

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely new context beyond that: it does not navigate or change device state, and screens may expose private information, which is a real operational caveat for an agent deciding whether to capture and surface the image.

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 short sentences, zero filler, with the core action front-loaded and the privacy caveat right behind it. Nothing could be cut without losing meaning.

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 zero-param read tool with full annotation coverage this is close to complete, but there is no output schema, so the description is the only place that could say what a caller actually receives (base64 image, file path, dimensions). That gap is minor but real for a screenshot tool.

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 tool has zero parameters, so the baseline of 4 applies. The description correctly says nothing about arguments, avoiding noise.

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 ("Capture the current TV screen") and adds a scoping qualifier ("without navigation") that tells the agent the screen state is not altered. It is not confused with any sibling, since none of shield_status/shield_connect/shield_logcat/etc. capture a screen, though it never explicitly distinguishes itself from them.

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?

Usage is only implied: "without navigation" hints the tool is for reading the current screen rather than driving the UI, but there is no statement of when to prefer this over shield_status or shield_apps, nor any precondition. An agent can infer intent but gets no routing help.

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