search_emails

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

Without annotations, the description carries full burden. It includes useful notes like 'include_content: Whether to include email content preview (slower)', but does not explicitly state that the tool is read-only, disclose auth requirements, or mention rate limits. Basic behavioral traits are implied but not fully transparent.

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 well-structured with a clear 'Args:' section listing parameters. It is front-loaded with the purpose. Though it is lengthy due to 12 parameters, this is justified given the 0% schema coverage. A slightly more condensed style could be used, but overall it is efficient.

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?

The description covers all parameters and states the return format vaguely ('Formatted list of matching emails'). With an output schema present, the return details are acceptable. However, it lacks critical context such as differentiating from sibling search tools (e.g., search_emails_advanced, search_by_sender) and clarifying whether 'any mailbox' includes multiple accounts or just the one specified.

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 0%, so the description fully compensates. Every parameter is explained with allowed values, defaults, and formats (e.g., read_status: 'all', 'read', 'unread'; date_from: 'YYYY-MM-DD'). This significantly helps an agent understand and use each parameter correctly.

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 'Unified search tool - search emails with advanced filtering across any mailbox,' which identifies the core function. However, given the many sibling search tools (e.g., search_emails_advanced, search_by_sender), it does not explicitly differentiate itself, leaving ambiguity about when to use this version over others.

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 provides detailed parameter explanations but offers no guidance on when to use this tool versus alternatives. It does not mention prerequisites, contextual triggers, or exclude other search tools, leaving the agent to infer usage without clear boundaries.

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