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

With no annotations, the description carries the disclosure burden and does reveal that this is a HIGH_WRITE operation, that omitting body includes the original message, and that eaccount/subject default from the original. However, the `confirm` parameter is never explained, and the NOTE's reply_to_uuid is absent from the input schema, leaving the agent unsure what it must actually supply.

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 definition is compact and front-loaded: purpose, write warning, and default behaviors appear in the first three lines. The trailing '# NOTE' block is formatted like code trivia and introduces a non-schema identifier, adding mild noise and confusion.

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 description covers purpose, write severity, and defaulting behavior, which is substantial for a 6-parameter tool. But it omits the semantics of `confirm` on a HIGH_WRITE tool, leaves the schema-to-API mapping (email_id → reply_to_uuid) unexplained, and with no output schema or annotations, an agent lacks enough guidance for safe invocation.

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?

At 0% schema coverage, the description is the only source of parameter meaning, and it does clarify `to` (comma-separated), `body` (omitting it includes the original), and `eaccount`/`subject` (default from the original). Yet `confirm`, a boolean defaulting to false on a write path, is completely undocumented, and `email_id` is never formally tied to the required reply_to_uuid.

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 first sentence, 'Forward a Unibox email to `to` (comma-separated addresses),' states a specific verb and resource with an operational detail about recipient format. The action is inherently distinct from its closest sibling, reply_to_email, so an agent can disambiguate without inspecting either 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?

No sentence tells the agent when to choose forward_email over reply_to_email or the other email tools. The description provides defaults and an API note, but no selection criteria, prerequisites, or exclusions — usage is only implied by the verb 'forward.'

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