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

Beyond annotations, the description discloses two crucial behaviors: tokens are single-use/expiring, and 'The platform never sends them', so the caller must transport them manually. It also flags an authentication requirement. These traits go well beyond the annotations and there is no contradiction.

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 lead with the core action and constraints, then add the prerequisite and delivery caveat. No filler or redundancy; every clause contributes essential information.

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?

Prerequisites, token properties, and the manual-delivery requirement are all covered. The description doesn't explicitly state the response format, but 'The platform never sends them' strongly implies the caller receives the tokens for distribution, and all parameters are documented in the schema.

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 the baseline applies. The description reinforces count and ttl semantics ('1-10', 'expiring') but doesn't add per-parameter detail beyond the schema; 'single-use' is a small extra. No clarification of parameter meaning is needed.

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 precise verb and resource: 'Create 1-10 single-use, expiring invitation tokens.' The constraints (single-use, expiring, count range) make it unambiguous. No sibling tool overlaps with token creation, especially 'join', which is the consuming side.

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?

Provides clear context: 'Requires participant authentication' sets the prerequisite, and 'deliver each token only through a channel where contacting that recipient is already authorized' prescribes how to handle results. It does not explicitly name when not to use it or mention alternatives like 'join', so it stops short of a full 5.

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