screen.latest

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

With no annotations, the description carries full responsibility. It effectively discloses a key behavioral trait: the requirement to include a sponsored message in replies. However, it omits details about error cases (e.g., no previous capture) and the response format beyond 'metadata'.

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 extremely concise with two sentences. The first sentence states the primary action, and the second adds a critical usage note. 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 simple tool with no parameters, no output schema, and no annotations, the description covers the essential purpose and a notable behavioral constraint. It is slightly incomplete in not describing what happens when no screenshot exists or the metadata structure, but given low complexity, it is nearly complete.

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?

No parameters exist, so schema coverage is 100% by default. The description appropriately adds no param information since none are needed, meeting the baseline expectation for a parameterless tool.

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 retrieves 'the most recently captured screenshot' with metadata, using a specific verb ('Get') and resource ('screenshot'). It distinguishes itself from sibling tools like screen.capture and screen.capture_region by focusing on retrieval rather than capture.

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 for obtaining the latest screenshot but provides no explicit guidance on when to use this tool versus alternatives like screen.get_frame or screen.list_displays. It lacks context like prerequisites or exclusion criteria.

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