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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description still adds real value by disclosing the error contract: failures arrive as a single-element list with api_error/task_error, dfs_timeout or dfs_unreachable, and must be checked before evaluating results.

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 compact lines with no filler: purpose first, then the error-handling caveat, then the only non-obvious parameter. Every sentence carries information the agent would otherwise have to guess.

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?

An output schema exists, so return values need not be described, and the read-only nature is covered by annotations. However, for a competitor-discovery tool the missing pieces are consequential: what 'limit' bounds (number of domains returned), any cost/rate caveats of the open-world lookup, and how this differs from dfs_competitors_domain.

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 0% across three parameters, so the description must compensate. It does explain 'workspace' (customer workspace slug, optional when only one workspace exists), but 'limit' (default 20) and the expected 'domain' format (bare domain vs. URL, subdomain handling) receive no explanation.

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?

The description states the resource and the criterion precisely: domains with a similar backlink profile, i.e. SEO competitors. An agent can tell it apart from list/summary tools like dfs_backlinks_list or dfs_backlink_summary, but it never contrasts itself with the closely related dfs_competitors_domain or dfs_domain_intersection.

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?

Usage is only implied by the phrase "SEO-Competitors". There is no explicit guidance on when to prefer this over dfs_competitors_domain, dfs_domain_intersection or dfs_backlinks_list, and no stated prerequisites for the domain input.

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