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

Goes well beyond the readOnly/openWorld annotations by disclosing cost and side-effect behavior: no new request and no charge are made, so the agent knows this is a cached read. It also specifies the empty-state behavior and points to `note` for metric definitions, which is exactly the operational context annotations cannot express.

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-loads the key fact (stored answer, no charge) in the opening clause before listing contents, and closes with the fallback and definition pointer. The metric enumeration is dense but each item is a real capability; a small trim of the long middle list would tighten it.

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 burden and does so by naming each returned metric plus the presence of a `note` field for definitions. It leaves the response shape (nesting, units, pagination of the weekly series) unspecified, which is a minor gap for a read-only overview.

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%: both `clientId` and `domain` are documented in the schema, including the domain default (client's Rank Tracker site, else its website). The description adds nothing further about parameter semantics, 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?

States a specific resource (a client's link profile) and enumerates the exact contents: referring domains, backlinks, broken backlinks, Rank, spam score, attribute/domain-ending mix, and weekly series. It also pins the source (the workspace's STORED DataForSEO answer), which separates it from the live-lookup sibling run_link_lookup.

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 fallback path: with no stored answer it reports that fact, and run_link_lookup is named as the way to buy a fresh answer. That is a clear when-to-use/when-not signal. It does not, however, distinguish itself from adjacent readers like get_referring_domains, get_link_anchors, or get_linked_pages, which an agent could plausibly confuse with this overview.

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