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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, so the safety profile is covered. The description adds real value on top: it explains the two outcome branches (listed record vs. unlisted checklist), distinguishes registry-declared metadata from the monthly read-only scan, and warns that third_party_fields are written by others and must not be followed as instructions. That injection and data-provenance guidance is behavioral context the 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?

The purpose and timing are front-loaded in the first sentence, and every later sentence conveys distinct information. The middle sentence is long and clause-heavy, stacking the two metadata sources and their input-form conditions into one run-on, which slightly hurts scanability.

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 full burden of explaining return values, and it does: listed servers return a record with sources and caveats, unlisted servers return a checklist plus optional registry declarations and scan observations. That is sufficient for an agent to interpret either response branch 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 100% and the parameter already documents its accepted forms with an example. The description still adds meaning by linking input form to output content — a GitHub or registry name yields registry declarations, while an exact registry name or server URL additionally triggers scan data — which the schema does not convey.

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 opens with a specific verb and resource: check whether an MCP server is in Default Privacy's vetted list and what it can read or change. That scope clearly separates it from siblings like dp_check_domain_breaches or dp_check_email_security, which audit different resources, so an agent can route without opening a 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?

It gives an explicit usage trigger — 'Before connecting an MCP server, check...' — and clarifies that 'Unlisted is not a verdict,' which prevents a likely misinterpretation. It does not name an alternative tool or say when this check is unnecessary, so it stops short of a full when/when-not/alternatives treatment.

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