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

With no annotations, the description carries the behavioral disclosure burden and does substantial work: it reveals the non-waiting semantics, the expect_reply default, room restrictions, and the encryption envelope requirement. It doesn't cover auth, rate limits, or failure/return behavior, but the included constraints go well beyond the schema.

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?

Every sentence earns its place. The description is short, front-loaded with the core behavior, and immediately gives the sibling alternative, defaults, prohibitions, and the encryption exception without padding.

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?

The tool has seven parameters and a nested parts object, yet the description does not explain how parts are used, what token represents, or what happens after a fire-and-forget send. The e2ee path and key constraints are covered, but an agent still has to infer too much about payload construction and return 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 description coverage is only 43%, and the description only partly compensates: it explains when to use envelope and mentions expect_reply's default, both of which appear in or are close to the schema. Parameters like text, parts, token, and in_reply_to receive no meaningful added semantic context in the description.

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 opening 'Send without waiting' gives a specific verb and mode that distinguishes it from send_and_wait, and the next sentence names the sibling explicitly. It could state 'message to a user' more directly, but the name plus the sibling contrast make the purpose clear.

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 explicitly routes live chat to send_and_wait, which is the key alternative. It also gives concrete negative guidance: don't send to #room, don't send 'ok', and use the e2ee envelope path instead of text when the peer has an encryption public key. This is strong usage direction.

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