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

Beyond the readOnlyHint/idempotent annotations, it discloses real behavioral details: organizer text is truncated to 3000 chars, venue/organizer names appear only if confirmed, and past events carry past:true while remaining an archival page. These edge-case behaviors are exactly the kind of context annotations cannot convey.

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?

One dense but well-front-loaded sentence that puts the resource and id sourcing first, then enumerates returned fields, then the past-event archive note. Information-rich with little waste, though the field enumeration is packed tightly.

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?

With no output schema, the description carries the return-shape burden and does so by listing the card's key fields and the past-event flag. Annotations cover safety; only minor gaps like exact field naming/format remain.

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% (baseline 3), and the description adds meaning the schema lacks: the id may be supplied either bare or as the full design-events.fun/event/<id> address. That clarifes accepted input forms beyond 'id события, как в url карточки'.

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 (retrieve the full event card by id) and enumerates what it returns: description, timezone, city, format, directions, links, venue/organizer. The id-based single-fetch scope clearly distinguishes it from the search_events/list_directions/plan_my_week siblings without opening a schema.

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?

It implies when to use it — you have an id or a card URL ('по id ... или по самому адресу'), so you fetch that one event. But it names no alternative (e.g. 'use search_events to find the id first') and gives no when-not-to-use condition, leaving the routing mostly to inference.

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