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

Annotations already declare a non-readonly, non-destructive, non-idempotent, closed-world write, so the burden is lighter. The description adds real behavior: the file is persisted to storage and a url is returned, plus the mutual-exclusivity input requirement. Auth, limits, and failure modes remain unstated.

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?

Three front-loaded sentences: purpose, input modes + resulting behavior/output, then downstream integration with the exclusivity rule. Every sentence earns its place with no preamble.

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?

No output schema exists, so the description correctly compensates by stating that a url is returned and where to use it. It omits any error/invalid-input behavior, which is the only gap for a 4-parameter write tool.

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 baseline is 3, but the description adds the cross-parameter constraint 'exactly one of url or file_base64', which is genuine value beyond per-field docs. filename semantics are left to the schema.

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?

Specific verb (upload/загрузка) plus a narrowly scoped resource (image for the 'media choice' answer-option widget), which implicitly separates it from the sibling upload_quiz_media and upload_workspace_logo. An agent can tell what this produces without opening the 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?

States the context clearly (answer-option images for the media-choice widget) and closes the loop by telling the agent to feed the returned url into choiceImageEntities[].link in update_quiz_widgets. No explicit 'when not to use' or named alternative to upload_quiz_media, so it stops short of 5.

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