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

Annotations already declare the safety profile (idempotent, destructive, open-world), and the description adds real value on top: what is returned (fresh preview JSON), the failure mode ('fetch failed' for private/blocked URLs), and the public-URLs-only scope. It does not, however, disclose that the refresh overwrites the existing stored card metadata, which is the destructive behavior the annotation flags.

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?

Four front-loaded sentences, each earning its place: purpose, trigger, return/failure behavior, and scope limit. The final note about per-provider OAuth is useful scope info though slightly roadmap-flavored.

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-param tool with no output schema, the description covers what it does, when to use it, what it returns (including the failure case), and its V1 limitation in one place. The only real omission is the overwrite/destructive effect on the existing card.

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?

With one parameter at 0% schema coverage, the description carries the burden, and it only partially compensates by implying documentId must reference a LINK-type document. It adds no format, ID-source, or validation detail beyond that implicit constraint.

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 (re-fetch) and resource (Open Graph metadata: title, description, image, site_name) scoped to a workspace LINK document. An agent can distinguish this from attach_link or get_document_metadata 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?

Explicitly gives the trigger: 'Used when the link card looks stale or the source page changed after the original attach.' Clear when-to-use context, though it does not name the sibling alternative (e.g. re-attaching via attach_link) or state when not to use it.

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