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

Annotations already cover non-destructive, open-world, write behavior, but the description adds substantial context beyond them: invite-email + one-time-code verification with no account, no email sent in domain mode, immediate effect, and allow-list scope relative to project restriction. One nuance keeps it from a 5: the claim that re-adding an existing entry is harmless and sends no second email reads as idempotency, which sits awkwardly with idempotentHint=false, though the safety-relevant hints (write, open-world, non-destructive) all agree.

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 purpose and primary mode are front-loaded, and each subsequent sentence carries real content (domain mode, consumer-domain exclusion, immediate effect, idempotent re-add, allow-list scope). It is dense - six sentences - but earns most of its length given the tool's two-mode complexity.

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?

With an output schema present, the description needn't explain return values, and annotations cover the safety profile. Everything an agent needs to choose the right mode, avoid consumer domains, and know the side effects (email, immediate effect, no account needed) is present.

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%, so both parameters are already documented, including the @company.com domain form for email. The narrative adds the rationale (consumer-domain refusal, added-to-allow-list effect) but no syntax or formatting detail beyond the schema, so the baseline 3 applies.

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 states a specific verb (share) and resource (a restricted spawnpoint project) and immediately distinguishes the two modes: one person by email vs. everyone at a domain. An agent can tell exactly what this does and how it differs from related tools such as set_visibility or unshare_project without opening a 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?

It gives explicit when-to-use for each mode (single email vs. @company.com), an explicit when-not (consumer domains like @gmail.com are refused), and an alternative action ("make the project public instead"). It also states the precondition that the allow list only matters while the project is restricted.

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