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

readOnlyHint=true already declares the safe-read profile, and the description adds useful context beyond that: it returns metadata only, never secret values, which matters for a credentials endpoint. The authentication/session requirement is also disclosed. It stops short of describing pagination or result shape, but the added disclosure is substantive.

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 purpose and result boundary in the first sentence, then the access requirement. The ACCESS paragraph is slightly long for a zero-argument list tool, but every sentence carries operational value (auth path and the session dependency).

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?

There is no output schema, but the description covers the return nature (credential metadata, not secrets) and the full auth/session prerequisite, which is the main thing an agent could get wrong on this tool. Nothing needed to invoke it correctly is absent.

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?

The tool takes zero parameters, so the baseline is 4 per the rubric and there is no schema semantics for the description to expand on. Nothing is required or missing here.

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 ('List all stored DNS provider credentials') with scope ('for the authenticated account') and explicitly bounds the result ('not secret values'). This cleanly separates it from create_dns_credential, delete_dns_credential, and get_dns_providers without needing 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?

The ACCESS block gives clear preconditions (needs a Proof account, authenticate first, or use start_login) and states that a session opens this tool. However, it never states when to prefer this over the similarly named get_dns_providers sibling, so alternative selection is left to inference.

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