Advanced email search

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

The annotations already provide readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false. The description adds a behavioral default not in annotations: 'Omitting filters lists recent mail,' and clarifies that searches can span one or all accounts, which is valuable context beyond the schema and annotations.

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 two-sentence structure is efficient, front-loading the use condition and enumerating filter categories without filler. The long first sentence is dense but serves to convey the breadth of search capabilities, and the second sentence succinctly captures fallback behavior.

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 26 parameters and no output schema, the description gives a strong high-level orientation but lacks per-parameter semantics and response/pagination details. It covers the main use case and default behavior, but an agent would still be uncertain about exact query construction and result handling, so additional description or schema documentation would improve 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?

With only 4% schema description coverage, the description must compensate for undocumented parameters. It lists filter categories like subject, body, date, attachment, size, and pagination, but does not map them to exact parameter names (e.g., 'read' vs 'unread', 'starred' vs 'flagged') nor explain enums such as folderScope or accountScope, leaving ambiguity for constructing calls.

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 states a specific resource (email) and action (search across one or all accounts) and enumerates the filtering dimensions (folder, sender, recipient, CC, BCC, subject, body, date, etc.), making the tool's purpose unmistakable. However, it does not explicitly distinguish this tool from the sibling 'search' tool, so differentiation relies on the 'Advanced' title and the filter richness.

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 opens with 'Use this when searching one account or all accounts...' which gives a clear condition for invocation. It also notes the default behavior when filters are omitted, but it does not specify when not to use it or point to alternatives like the sibling 'search' tool.

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