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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false), and the description adds genuinely useful scope context the annotations cannot: the token is opaque, it identifies a human account, and it explicitly grants no private Space or DM access. It stops short of disclosing idempotency (does a second call mint a second token?) or revocability, which matters for a credential-like object.

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?

Two short sentences, zero filler. The positive behavior is stated first and the security caveat second, so the most important qualification is not buried.

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-value details are covered elsewhere, and with no inputs the description carries little remaining burden. The gaps are the credential lifecycle questions (idempotency, revocation, whether the token can be shared repeatedly) and the pointer to resolve_contact_link, which keep it from a 5.

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 (additionalProperties: false), so there is nothing for the description to disambiguate. Baseline 4 applies; the absence of arguments is itself consistent with the 'create a link for yourself' semantics.

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?

Specific verb+resource: creates an opaque contact token that identifies the caller's human account and the verified actor. That is concrete enough to distinguish it from most siblings. It does not name the paired sibling (private_space_resolve_contact_link), so the create/resolve pairing must be inferred from names alone.

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: the token exists to be handed out so a counterparty can resolve back to the human account. There is no explicit statement of when to call this versus resolve_contact_link, nor any prerequisite (e.g. actor must be verified/registered) beyond the phrase 'this verified actor'.

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