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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is fully covered. The description adds value by enumerating the returned fields unambiguously (platform info, title, description, author, engagement stats, tags, creation date), but doesn't mention failure modes for unsupported platforms/private content or rate limits.

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 sentences, zero waste: scoping clause, return-value clause, sibling-routing clause. Front-loaded with the core action and platform list.

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?

For a single-parameter read tool with full annotation coverage, no output schema, and no nested objects, the description covers purpose, scope, return contract, and alternative routing. Nothing an agent needs to invoke it correctly 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 description coverage is 100% and only one parameter exists, so the schema already documents the URL. The description confirms platform support but adds no syntax or format guidance beyond what the schema property description provides. Baseline 3 is appropriate.

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 (Fetch) and resource (metadata from a media URL), enumerates supported platforms, and names the sibling it is not (supadata_transcript) with a crisp distinction between details vs. spoken content. An agent can route between them without opening either 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?

Explicitly says when to use this tool ('details about a video or post') versus the alternative ('use supadata_transcript for what is said in it'). The only missing piece is explicit single-URL scoping, which is implied by 'a media URL'.

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