browser_when_changed

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

No annotations are provided, so the description carries full burden. It mentions the data source (recorded timeline + storage keyframes) and notes storage granularity. However, it doesn't disclose edge cases like behavior when no change is found, rate limits, or whether the operation is read-only.

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 three sentences, front-loaded with the core concept, and each sentence adds essential detail: target types, anchor options, and data source. No redundant text.

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?

Given 5 parameters, no output schema, and no annotations, the description covers purpose and typical usage but lacks details on return format, error handling, and behavior when no change is found. It is adequate but not comprehensive.

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 the schema already documents all parameters. The description adds concrete examples (e.g., type=storage with key='token') and clarifies the 'before' parameter options, but does not add significant new semantics beyond the schema.

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 'BACKWARD DATA-BREAKPOINT' and clearly states the tool finds when something last changed before a moment. It distinguishes from siblings like browser_timetravel or browser_query_timeline by focusing on last-change queries.

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 explains when to use (to find last change before a moment) and gives examples of targets and the 'before' anchor. However, it does not explicitly exclude alternatives or guide selection among siblings like browser_query_timeline.

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