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

Annotations cover the safety profile (readOnlyHint=false, idempotentHint=false, openWorldHint=true), and the description adds meaningful context beyond them: accepted formats, the 50 MB ceiling, the https/public-source constraint, and the uuid return contract. It does not mention auth requirements or failure modes for oversized/unsupported files, so it falls short of 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?

Front-loaded with the core action, then formats, size limit, return value, and usage routing in tight sequence. The trailing French translation is somewhat redundant for an English-reading agent, but it is short and clearly delimited.

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 contract (media uuid) itself, plus format and size constraints and the downstream tools that consume the uuid. An agent has everything needed to call it and use the result correctly.

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 75% and the schema itself documents url, type (with enum values) and filename. The description only reinforces that the URL must be public https and that the result feeds `media_uuids`; it adds little parameter-level detail beyond the schema, so the baseline 3 applies.

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?

Names a specific verb+resource ('Download a media file from a public https URL and add it to the workspace library'), enumerates supported formats, states a 50 MB cap, and states the return value. It is clearly distinguishable from siblings like generate_ai_text or list_posts.

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?

Explicitly says when to use it ('when the user supplies a link to an image or a video') and when not to ('it does not search the web for one'), and routes the agent forward by naming create_draft_post and create_stories and the `media_uuids` field to pass the result into.

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