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

Annotations already declare readOnly, idempotent, non-open-world and non-destructive, so the safety profile is covered. On top of that the description discloses genuinely non-obvious behavior: the `access` gate vocabulary and what an absent value means, truncation reporting, the empty-window fallback to the next event, and the `townScope.recognized: false` failure mode with `didYouMean`. That is substantive disclosure beyond the annotations, though it never states rate limits or latency.

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?

Purpose is front-loaded in the first clause and the remainder is dense but load-bearing detail about return shape. It is a single long paragraph with several clauses chained by semicolons, which is efficient but makes the access-gate enumeration harder to scan than a short list would be.

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?

There is no output schema, so the description carries the full burden of describing the return value, and it does: total matching count, truncation flag, per-row `sourceUrl` and check date, `access`/`accessNote`, `townScope`, and `didYouMean` on empty results. For a 4-parameter, zero-required read tool with annotations already covering safety, nothing an agent needs in order to call it and interpret the answer is missing.

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 the baseline is 3, but the description earns extra credit by explaining how the `town` argument is interpreted (`townScope` reporting, near-match `didYouMean` when the name resolves to no East End place) and the effective result cap of 12, neither of which is in the schema. It does not elaborate on the `who` enum beyond what the schema description already says.

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 names a specific resource (East End events) inside a specific scope (a date window) and states the verification property of each row (`sourceUrl` plus last-checked date). That is enough to distinguish it from vague siblings like things_to_do or plan_my_day on substance, but it never explicitly contrasts itself with those calendar-adjacent siblings, so the agent must infer the split.

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?

Usage context is implied rather than stated: the window defaults to the next 7 days, returns up to 12 rows, and falls back to the next in-scope event when nothing matches. There is no explicit when-to-use-this-instead-of guidance (e.g. versus things_to_do or whats_open_now), so the agent gets operational framing but no routing rule.

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