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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description does add genuine value by enumerating the possible states (queued, held, delivered, read, refused, expired) and the reply fields returned, but it says nothing about auth needs, retention semantics beyond 'what Licium keeps', or the 'note' behavior.

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?

It is a single run-on sentence mixing four distinct concerns (state, reply status, retention, next-step note) with an awkward fragment 'and note: one sentence on what happens next.' No front-loaded verb or summary, so the reader must parse to the end to learn the tool's purpose.

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 no output schema, the description does carry the return-value burden and lists the key fields. However, it omits what the `id` parameter identifies and how the four pieces relate, and it lacks any guidance for a tool that sits among many status-check siblings.

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%: agent_key is documented in-schema, but the required `id` (fixed 36-char string, presumably a message ID) has no description anywhere. The tool description never mentions either parameter, so it does not compensate for the gap and leaves the caller unsure what `id` refers to (message vs. thread).

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 enumerates what the response contains (delivery state, reply info, retention, next-step note), which implies a status lookup for a sent message, but it never states a verb or resource directly ('Where a message you sent is...'). An agent can infer it queries message delivery status, yet it doesn't distinguish itself from siblings like connect_inbox, connect_watch, or receipt.

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?

There is no statement of when to call this versus alternatives such as connect_inbox (inbound), connect_watch (monitoring), or receipt. The only hint is 'message you sent', leaving the agent to guess the routing.

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