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

Annotations already declare readOnlyHint=true and destructiveHint=false, yet the description adds real value: it discloses the return contract ('OK or error message, e.g. no SEP matching DS') and the external prerequisite ('requires delv installed; if not, returns clear message'). This environment dependency is exactly the kind of context the annotations cannot carry.

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 short clauses, front-loaded with the action and mechanism, then return shape, then prerequisite. Every sentence earns its place with zero filler.

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?

Output schema exists so return values needn't be spelled out, but the description still summarizes them and flags the delv dependency, which is the main failure mode. Complete enough for an agent to call correctly; only missing explicit sibling routing.

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 both parameters are documented there, so the description adds no parameter-level detail beyond what the schema provides. 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 verb and technical scope: 'Validate DS → DNSKEY chain for a domain (via delv)'. This is clearly distinct from generic lookups like dns_lookup or azure_dns_lookup, though it does not name a sibling to contrast against explicitly.

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?

Implicitly tells the agent to use this for DNSSEC chain validation, but gives no explicit when-to-use vs. dns_lookup/dnssec alternatives, and no guidance on when validation is unnecessary (e.g. unsigned zones).

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