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

With no annotations, the description carries the full burden. It explicitly states the tool produces a summary and does not return complete data, which is a key behavioral trait. It also specifies the content of the summary (count/duration/type distribution). However, it does not mention auth, rate limits, or response format, but for a simple read tool this is acceptable.

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, using a single sentence with parenthetical clarifications. It front-loads the purpose and adds the key 'no full data' exclusion. The English 'rrweb summary' is somewhat redundant but does not detract.

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 the tool has only one parameter and no output schema, the description provides the essential information: what it returns (event count/duration/type distribution) and what it excludes (complete data). It does not describe the report_id parameter, but that is covered under parameter semantics. The description is sufficiently complete for an agent to know when to invoke it and what to expect.

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%, and the description does not mention the single required parameter report_id. The description adds no meaning about what report_id is, its format, or how it affects the result. The parameter name is self-explanatory, but the description fails to compensate for the lack of schema documentation.

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 provides a summary of DOM trajectories (rrweb data), specifically listing what the summary includes (event count, duration, type distribution). It also explicitly says it does not return complete data, which distinguishes it from the sibling tool get_rrweb_events.

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 this tool is for obtaining aggregated summary metrics rather than full rrweb event data, giving clear context for when to use it. However, it does not explicitly name alternative tools or state when-not-to-use conditions, so it falls short of a 5.

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