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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the description's added value is in disclosure of result behavior: at most 10 items, ranked 'best first', and each carrying time, venue and link. It does not discuss empty-result behavior or how 'best' is computed, which keeps it from a 5.

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: the first front-loads scope, result cap and ordering plus returned fields; the second is a compact usage example. No sentence is redundant or restates the title.

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 two-parameter, zero-required read tool with rich annotations and a fully documented schema, the description supplies everything an agent needs: time window, result count, ordering, and returned fields. No output schema exists, and the field list in the description compensates for that.

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%, including per-value enum explanations and the YYYY-MM-DD pattern, so the schema already carries parameter meaning. The description only reinforces this with the sample call date='2026-11-07', category='music', adding marginal semantics beyond the structured fields.

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 resource (events in Amsterdam) with the exact scope: one day, today through six days ahead, drawn from the What's On calendar. It also distinguishes itself from same-city siblings like markets_today and conferences by naming the calendar and the returned fields (time, venue, link).

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 usable window ('today to six days ahead') and the optional category filter give clear conditions for calling it, and the example shows the intended date format. It stops short of explicitly routing the agent away from overlapping siblings such as conferences or markets_today, so no true exclusion guidance is present.

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