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

With no annotations, the description carries the full burden, and it does disclose real outward-facing behavior: an email is sent from the caller, it offers to link the recipient, and it expires in 7 days. It also states credential and wallet_id requirements. Still missing: whether resending is allowed, rate limits, and what the call returns.

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 core action and the expiry constraint are front-loaded in the first two sentences. The language enumeration is long but earns its place because the schema provides no enum. The closing credential sentence is slightly tacked on but useful.

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, and the description still omits what happens on success or failure, so the agent cannot know the response shape. Against that, the description covers the side effect, expiry, language handling, and auth prerequisites for a five-parameter tool, so coverage is broadly adequate.

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%, so baseline is 3. The description adds real meaning beyond the schema by enumerating the supported language codes and defining absent/unsupported behavior as English, and by identifying wallet_id as required. The message and device_name parameters are unexplained in the description, though the schema itself notes them.

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 gives a concrete verb and resource: email someone an invitation to join Provian, from you, with a link-back offer and a 7-day expiry. It explicitly points to sibling invite_human for beneficiary invitations. It does not distinguish plain invite from invite_device, which is left to schema hints, so sibling differentiation is only partial.

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 states the condition that selects a sibling: 'When you are asking a person to become your beneficiary, call invite_human.' That routes the agent away from this tool for the beneficiary case. It gives no guidance on invite_device versus this tool, nor any when-not-to-use conditions such as re-inviting an existing member.

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