mail_parse_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 metadata fields will be null since the message is not in the mail store, and hints that blob_ids come from mail_download_attachment. This provides sufficient behavioral context for a read-only parse operation.

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 description is short and well-structured: a one-line summary, then a blank line, then practical usage context, then parameter details. Every sentence is informative and there is no fluff.

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?

Given the tool's simplicity (1 parameter), the description covers the use case, parameter origin, and special behavior of metadata. The output schema exists to document the return format, so no further explanation is needed.

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?

The description explains the single parameter blob_ids as 'list of blobIds to parse' and provides a helpful hint about its origin (e.g., from mail_download_attachment). This adds value beyond the schema, which has no description coverage.

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 clearly states 'Parse one or more blobs as RFC 5322 messages without importing them', which distinguishes it from mail_import_email and other mail tools. It also mentions specific use cases like viewing .eml attachments.

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 states the tool is useful for viewing .eml attachments or forwarded messages stored as blobs. It implies when not to use (for importing messages) but does not compare with other siblings like mail_export_email or mail_get_email.

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