list_emails

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

Annotations already establish read-only and idempotent behavior; the description adds meaningful context by disclosing newest-first ordering, pagination support, and that only envelope summaries plus uidvalidity are returned. This goes beyond the structured metadata without contradicting it.

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?

Two focused sentences deliver the essential scope, ordering, pagination, and return value. Every word adds value, 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?

Given a 4-parameter tool with full schema descriptions and an output schema, the description adequately covers core behavior, including return type and order. It does not elaborate on alternative tools, but that is more of a usage-guideline gap than a completeness gap for this simple listing operation.

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 the baseline is 3. The description's mention of 'newest first, with pagination' implicitly relates to limit/offset but adds no meaning beyond the schema's own parameter descriptions, which already document folder, limit, offset, and unread_only.

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?

Description uses a specific verb-resource pair ('List messages in a folder') and adds ordering and pagination details, making it clear this tool retrieves message envelopes from a named folder. This distinguishes it from siblings like get_email (single message), search_emails (query-based), and list_folders (folder list).

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 usage for browsing a folder's messages and mentions pagination, but it does not explicitly state when to choose this over search_emails or get_email. It provides no exclusions or alternative recommendations, so guidance is only implicit.

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