sync_email

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

With no annotations provided, the description carries the full burden. It discloses the per-folder UID checkpoint (indicating incremental sync), required environment variables, and the default folder. It does not hide any side effects.

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 divided into a one-sentence summary, a behavioral paragraph, environment variable requirements, and an Args section. Every sentence adds value and there is no redundancy.

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 simplicity of the tool (2 parameters, no output schema), the description covers all necessary aspects: purpose, behavior (UID checkpoint), prerequisites (env vars), and parameter details. It leaves no ambiguity.

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 input schema provides only type and default for folder and max_emails. The description adds meaningful context: folder options with examples like '[Gmail]/Sent Mail', and max_emails as a cap per sync. This fully compensates for the missing schema descriptions.

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 starts with 'Sync Gmail messages into memory via IMAP.', clearly stating the verb (sync), resource (Gmail messages), and mechanism (IMAP). It distinguishes itself from sibling sync tools (e.g., sync_slack, sync_discord) by targeting email, specifically Gmail.

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 mentions that it fetches emails from a Gmail folder and stores them for search, and explains that it uses a UID checkpoint to avoid re-ingesting. It does not explicitly state when not to use it, but the context is clear for Gmail email syncing.

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