imap_forward_email

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

No annotations are provided, so the description carries the full burden. It discloses that the original message is quoted, headers are included, attachments are optionally included, and that account defaultBcc addresses are always BCC'd when configured. This is meaningful behavioral context beyond the schema. It doesn't mention whether forwarding marks the original as read or what the return value is, but the disclosed behaviors are the most decision-relevant ones.

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?

Three sentences with zero waste. The core action and quoting behavior are front-loaded, the usage guidance follows, and the defaultBcc caveat is placed last. Every sentence earns its place.

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 9-parameter tool with no annotations and no output schema, the description covers the essential decision factors: what the tool does, when to use it, the quoting behavior, attachment handling, and the defaultBcc side effect. It doesn't describe the return value or error conditions, but the description is complete enough for an agent to select and invoke the tool correctly in most cases.

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 100%, so the schema already documents all 9 parameters. The description adds context for the 'to' parameter (forwarding to new recipients) and the defaultBcc merge behavior, but it doesn't add syntax or format details beyond what the schema provides. Baseline 3 is appropriate when the schema does the heavy lifting.

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 states a specific verb ('Forward'), a resource ('an existing email (folder + uid)'), and the key behavior ('quoting the original message and headers'). It also explicitly distinguishes itself from imap_reply_to_email, which is the closest sibling. An agent can tell this tool apart from the reply tool without opening 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?

The description gives explicit when-to-use guidance: 'Use when the user wants to pass an existing message on to someone else; use imap_reply_to_email instead to respond to the sender.' This names the alternative and the condition that selects it, leaving nothing to inference.

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