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

Annotations already state readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds meaningful cost behavior and the re-purchase caveat, but the pricing is self-contradictory: 'at least 10 Nexscope credits' versus '1 credit per request', which leaves the agent unable to predict spend.

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 text reads as pasted marketing copy with duplication: the purpose is restated twice, 'Facebook Events Events API View Pricing' is boilerplate, and pricing is stated in two incompatible ways. The useful first sentence is front-loaded, but much of the remainder does not earn its place.

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?

For a read-only, three-parameter tool with complete schema coverage and no output schema, the core purpose, data source, and cost caveat are present. It falls short on pagination semantics for cursor, on how results are ordered or scoped by the time filter, and on any differentiation from the other Facebook events tools.

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%, so url, time (with an enum), and cursor are fully documented in the schema. The description adds only an example source page for the url shape and says nothing about how cursor pagination works or what 'all time' default means in practice, so the baseline of 3 applies.

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 opening sentence 'Get the events of a city' is a clear verb+resource and the example link grounds it in the Facebook Events explore page. However, it never distinguishes itself from nearby siblings such as social_facebook_events_search, social_facebook_profile_events, or social_facebook_event_details, so an agent cannot tell from the description alone which of these to pick.

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?

There is no explicit when-to-use or when-not-to-use guidance and no named alternatives. The only usable hints are implicit: the required param is a city's Facebook Events page URL, and the note that 'repeated requests may purchase data again' warns against redundant calls, but the agent must infer the selection criteria and prerequisites.

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