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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), and the description adds behavior those annotations cannot express: the setup_required error means no app is connected and the agent must surface the link rather than report zero reviews, and syncing means the first sync is still running. The "do not report zero reviews" guardrail directly prevents a serious misinterpretation of results.

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?

Front-loaded with what the tool returns, followed by usage, a compact example, and error-state handling in two short clauses. No filler sentences; each one conveys distinct information.

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 shape need not be explained. Given four optional parameters with defaults, the description covers the derivation of sentiment, a usage scenario, an example, and the two non-obvious error states — everything an agent needs to call and interpret 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 100%, so parameters are already documented with formats and defaults; the description adds the semantic that sentiment buckets are derived from star ratings (4-5/3/1-2) and shows a working payload with interval and since. That goes beyond the schema's "Bucket size." without duplicating it.

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+resource: review counts split into positive/neutral/negative buckets plus average rating, bucketed per day/week/month. It also clarifies that sentiment is derived from the star rating, which removes ambiguity about how the classification is produced. It does not explicitly distinguish itself from the sibling review_stats, which is the main thing keeping it from a 5.

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 to spot when ratings changed, e.g. after a release" gives a concrete usage context, and the embedded example call shows a realistic invocation. It stops short of naming an alternative (e.g. review_stats) or stating when not to use it, so the routing guidance is clear but not complete.

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