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

Annotations already declare this a safe, idempotent, non-open-world read, so the bar is lower. The description goes beyond them by disclosing the critical trait that rendering happens in the visitor's browser and that the tool returns only a link, never a video file, plus the watermarked-MP4 download step. It stops short of auth or rate-limit details.

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?

Three sentences, front-loaded with the core purpose and artifact. Each sentence carries distinct information (what the clip shows, what the visitor gets, what the tool returns), though the dense phrasing is slightly long for the amount of structured data already available.

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?

There is no output schema, so the description must explain the return value, and it does so explicitly ('returns the link only, never a video file'). With 8 parameters at 75% schema coverage, the remaining gap is minor, making this largely complete for an agent to call it correctly.

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 75%, so the schema already documents most parameters including defaults and bbox ordering. The description adds conceptual meaning (borders/event layers, year transitions, title, labels, vertical vs landscape) but no format or constraint details beyond the structured fields, matching the baseline for high schema 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?

States a specific verb (build a link) plus the resource (RewindMap short-video maker with a map clip) and describes exactly what the link produces. It is clearly distinguishable from find_polity, search_events, and world_at_year, which retrieve data rather than generate a shareable artifact.

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 usage by explaining what the generated link does, but never states when to choose this over the sibling tools (e.g. 'use this to produce a shareable clip, use world_at_year for raw data'). No explicit alternatives or exclusions are offered, so the agent must infer the routing.

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