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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds useful content-level detail — the headline aggregate categories — but nothing about freshness of the data, aggregation window defaults, or any rate/caching limits. 'Takes no input' is also misleading in a tool whose schema exposes an optional shaping parameter.

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 sentences, front-loaded with the resource and its aggregates before the usage cue. The trailing 'Takes no input' is short but slightly redundant with a zero-required-parameter schema and slightly inaccurate, so it costs a point.

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?

An output schema exists, so return values need not be explained, and the description covers purpose, contents and a usage cue for a single-optional-parameter read tool. The only real gap is routing guidance among the numerous sibling market-sales tools, which matters given how many near-neighbors exist.

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 100% and the description correctly notes that no required input is needed, so the baseline applies. However, 'Takes no input' arguably discourages the agent from using the optional `fields` projection parameter, which is the opposite of what the schema documents.

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?

Names a specific resource (the domain sales pulse) and enumerates its contents (windows, price bands, sold-before count), which is a real verb+resource statement rather than a restatement of the title. It implicitly separates itself from siblings like series, lengths, endings and movers by calling itself 'headline aggregates', but it never names an alternative, so differentiation is inferred rather than stated.

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?

"Use it when someone asks how the domain sales market is doing overall" gives a clear triggering condition and scope. There are no exclusions or pointers to the more granular siblings (ud_get_market_sales_lengths, ud_list_market_sales_series, ud_list_market_sales_movers), which an agent would want when the question is narrower than 'overall'.

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