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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the safety profile is partially covered. The description adds genuinely useful context beyond that: credentials will be exposed in the AI conversation context, and the tool requires an authenticated session established via a second call. It does not clarify what the 'destructive' aspect means (e.g., whether existing providers are replaced).

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-loaded with the core action in the first sentence, followed by the credential-sensitivity warning and then the access prerequisites. Every sentence earns its place; the only mild redundancy is restating the credential warning and auth flow at some length.

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 mutation tool with destructive annotations and no output schema, the description covers the prerequisites and a notable security caveat (credential visibility). It leaves open what the destructive side effect is and what happens to previously configured providers, which is the main remaining gap.

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%, with id, provider, and credentials each documented in the schema, so the schema carries the parameter burden. The description adds no format or syntax detail beyond what is already there. Baseline 3 is appropriate.

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 resource plus a meaningful qualifier: 'Add an additional DNS provider for verification to an already-verified domain.' That scope constraint distinguishes it from the broader set of connect_*/create_dns_credential siblings, though no sibling is named explicitly. Clear enough that an agent knows what the tool does 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?

Gives real preconditions: the domain must already be verified, a Proof account is required, and it spells out the auth flow (authenticate via /mcp or start_login, then re-call). It does not explicitly contrast with alternatives like connect_dns_provider or create_dns_credential, so it stops short of a 5, but the when-to-use context is concrete.

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