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

Annotations already declare readOnlyHint=true, and the description adds genuine value: it explains the semantics of the output (per-pixel temporal statistics, bright areas = activity) and states it returns an image block plus attribution. It doesn't touch auth or rate limits, but for a read-only summarization tool this is above the bar.

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 tight sentences with the core transformation front-loaded and the elaboration following. Efficient, with little wasted text, though the output note could be merged more cleanly.

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?

With four parameters at 0% coverage and no output schema, an agent needs more than this: the meaning, allowed values, and defaults of asset/db/max_size are unknown. The description does cover the return shape, but the parameter gaps make it incomplete for correct invocation.

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% across four parameters, so the description must compensate. It only clarifies the required 'urls' parameter (STAC URLs of passes) and leaves db, asset, and max_size completely unexplained, leaving most of the schema opaque.

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 and transformation: 'summarize a whole time series into one activity image,' elaborated as per-pixel temporal statistics where bright areas mark activity. This is distinguishable from siblings like quicklook and stack_stats, though it doesn't explicitly contrast with them.

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?

Says to pass STAC URLs of a site's passes, which implies when the tool applies, but there is no explicit when-to-use vs when-not, and no named alternative such as quicklook or change_composite for overlapping needs.

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