download_media

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

With no annotations, the description carries the full burden. It discloses that the operation is read-only ('read-only (download_*)') and writes locally ('на диск (локально)'), which is valuable. But it omits potential side effects like file overwriting, permission requirements, or error behavior, making it only partially transparent.

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 description is concise, with three sentences that each add value: the main action, a usage pattern, and scope/read-only notes. The code snippet is useful but adds minor overhead; overall it is well-structured and front-loaded.

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?

The output schema is present, so return values are covered elsewhere. The description provides a usage pattern and a clear scope, but does not address edge cases like messages without media or file-naming behavior. Still, for a straightforward download tool, it is fairly complete.

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 0%, so the description must compensate. The code snippet provides context for message_id and dest but does not explicitly explain the 'chat' parameter. It gives the relationship between parameters but lacks detailed semantics for types or constraints, so the compensation is partial.

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 description clearly states the tool downloads a specific message's attachment to disk locally, using the verb 'Скачать' (download) and the resource 'вложение из конкретного сообщения' (attachment from a specific message). It explicitly distinguishes itself from bulk operations with 'Точечно, не «все фото»' (Specifically, not all photos), and the code snippet reinforces the exact action.

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 description provides clear usage context with the workflow 'get_messages(entity, ids=message_id) → message.download_media(dest)' and an explicit exclusion 'не «все фото»' (not all photos). However, it does not name an alternative tool for bulk downloads, so it falls short of a 5.

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