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

Annotations already flag this as a non-readonly, destructive, non-idempotent, open-world write. The description adds context the annotations cannot express: the privilege-escalation guard ('cannot grant a role above the consenting user's own') and the human-approval-link path for ask-policy connections. It stops short of covering non-idempotency consequences (e.g., duplicate email invites) or what the destructive hint actually destroys.

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 tightly written sentences with the core action front-loaded and the two limiting constraints following. No filler, nothing redundant.

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 and rich annotations cover return values and the safety profile, so the description needn't repeat them. The added permission and approval-policy notes make it usable, though it omits edge cases an agent might hit (already-a-member email, invite expiry/resend behavior).

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 50%: 'role' is described, 'email' is not. The description repeats the enum values (member, admin, owner) that the schema already lists, adding little, but it does contribute one genuine semantic constraint: the inviter's own role caps what can be granted. With schema doing half the work and no email format guidance, a 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 ('Email an invitation') and resource ('join the workspace') with a scoping detail (role). This is cleanly distinguishable from siblings like fillo_change_member_role, fillo_remove_member, and fillo_list_members, which operate on existing members rather than inviting new ones.

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 description implies the use case (inviting a new teammate) and states two real constraints: you cannot grant a role above your own, and ask-policy connections require a human approval link. However, it never explicitly says when to use this versus alternatives (e.g., fillo_change_member_role for existing members) or what happens on duplicate invites, so guidance is implied rather than explicit.

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