ui_page_context

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

No annotations are provided, so the description carries the full burden. It discloses that the result is compact and low-token and lists the scoped context categories, which is useful. However, it does not explicitly state whether the operation is read-only, whether the context may be stale, or whether any side effects occur. For a context-reading tool this is adequate but not exhaustive.

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 sentences with no filler. The first sentence states the core function and output scope; the second gives usage guidance and the relationship to ui_snapshot. Everything included earns its place.

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?

The tool is simple, has an output schema, and one optional parameter. The description supplies the key routing decision against ui_snapshot and explains the compact nature of the result. The only real gap is the uninterpreted max_results parameter, which is minor but prevents a perfect score.

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 only parameter, max_results, has 0% schema description coverage and is not mentioned in the description. The name hints at a result cap, but the description adds no meaning beyond the raw parameter name and default value, so it fails to compensate for the low coverage.

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, '返回' (return), and precisely enumerates the resource scope: current page, active iframe, and focused overlay. It also distinguishes itself from ui_snapshot by calling this a compact/low-token context, so an agent can tell them apart without opening schemas.

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?

It explicitly states when to use this tool: every time the AI prepares its next interaction, as a low-token entry point. It also says to continue to ui_snapshot only when a detailed control tree is needed, providing clear when-to-use and when-not-to-use guidance with a named alternative.

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