list_emails

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 tool returns sender, subject, date, and snippet for each message, which is helpful. However, it does not mention default behaviors (e.g., default INBOX label, maxResults limits) or any side effects. The read-only nature is implied but not explicitly stated.

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 two sentences, front-loaded with the core action ('List emails from Gmail') and quickly presents filtering and return information. Every word earns its place with no redundancy or filler.

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 tool with 3 optional, fully documented parameters and no output schema, the description adequately covers the purpose, filtering options, and return format. The main gap is the lack of guidance on when to use this tool versus the sibling 'search_emails', which would improve contextual completeness.

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 baseline is 3. The description adds value by naming the return fields (sender, subject, date, snippet), which are not present in the schema. It also reinforces the filtering semantics of labelIds and query, though this is largely redundant with the schema.

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 the action ('List emails'), the target system ('Gmail'), and the scope ('filter by labels and/or a search query'). It also specifies the return fields (sender, subject, date, snippet). However, it does not explicitly distinguish itself from the sibling tool 'search_emails', which may perform a similar function.

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 implies the tool is used for listing emails with optional filters, providing context for typical use. However, it offers no explicit guidance on when to prefer this tool over alternatives like 'search_emails', nor does it mention any exclusions or use cases to avoid.

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