screen_search

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

With no annotations, the description carries the full burden. It discloses the tool is read-only ('Does not touch device') and explains query behavior. However, it does not describe return value, error cases, or behavior when no snapshot exists, limiting transparency.

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 very concise (two short sentences) and front-loaded with the core purpose. It efficiently conveys key information without fluff, though a bit more structure (e.g., bullet points) could improve readability.

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 2 parameters and no output schema, the description covers the purpose and primary parameter reasonably well. However, it lacks any mention of output format, error handling, or dependency on a prior snapshot, leaving gaps for the agent.

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%, so baseline is 3. The description adds minor value by explaining the default substring behavior and providing a regex example. However, it does not clarify ambiguous terms like 'auto' from the schema description.

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 action ('Filter last snapshot') and the resource ('last snapshot'). It distinguishes from sibling tools like screen_snapshot and screen_shot by specifying that it searches within an existing snapshot and does not touch the device.

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 provides parameter usage hints (substring default, regex syntax) but does not specify when to use this tool over alternatives, prerequisites (e.g., need a snapshot first), or scenarios where it is not appropriate.

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