Observe Action Result

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

Annotations already mark destructiveHint=true, so the destructive nature is known. The description adds a sensitivity warning about sensitive raw page data in the diff. It does not contradict annotations, but beyond that, it does not disclose additional behavioral traits such as side effects on page state or rate limits.

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 four sentences with clear front-loading of purpose and usage. Every sentence adds value: when to use, preconditions, next steps, and sensitivity. No unnecessary information.

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 description covers purpose, usage, and output context (diff with DOM, state, network, screenshot). However, given the high parameter count (7 with nested objects) and lack of parameter explanations, it is not fully complete. Output schema existence reduces the need to describe return values, but parameter semantics remain a gap.

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 description coverage is 0% for the 7 parameters (many nested). The description does not explain any parameter individually, such as the 'action' variant details or the snapshot options. This leaves the agent to infer from the schema alone, which is insufficient given the complexity.

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 starts with 'Use when one click, type, press, check, select, hover, scroll, reload, navigate, or authorized eval has an unclear outcome and a compact before/after diff is needed.' This clearly states the tool's purpose (observing action results) and distinguishes it from siblings that perform actions or take snapshots without the diff context.

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 specifies when to use (unclear outcome, need compact diff), preconditions (active page, acknowledgeRawCapture, acknowledgeDangerousEval for eval), and next steps (use returned diff to decide if longer monitoring is needed). It does not explicitly list when not to use or name alternative tools, but the context is clear.

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