mail_forward

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

With no annotations, the description carries the full burden and delivers: the note is pasted above the original in a visible Mail window, AppleScript content is not set, sends are verified in Sent/Outbox before success, and it distinguishes timeout vs TCC failures including error codes -1743/-10004 and hang-recovery matching. This is genuinely rich behavioral disclosure.

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?

Purpose is front-loaded in the first sentence, followed by confirm and verification behavior. The trailing sentences on TCC codes and hang recovery are dense but each carries actionable retry guidance, so little is wasted even if the density is high.

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?

For a 7-parameter mutation tool with no annotations and no output schema, the description covers send verification, timeout semantics, retry rules, and the optional note behavior. It is largely self-sufficient, with only minor gaps such as what the success/preview response actually contains.

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 every parameter is already documented in the schema, and the description mostly restates these (note mechanism, confirm requirement). It adds little parameter-level meaning beyond what the structured fields provide, so 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?

States a specific verb+resource ('Forward an existing email to new recipients') and implicitly separates itself from mail_reply by noting it shares the same System Events prepend mechanism. An agent can identify this as the forward action rather than reply or send.

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?

Gives concrete operating conditions: multi-recipient sends require confirm=true, a preview-only path exists, and clients must Sent-check before retrying a timed-out send. It stops short of an explicit 'use this instead of mail_reply/mail_send when X' routing statement, so it is clear context without full alternatives mapping.

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