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

With readOnlyHint and openWorldHint already declared, the description adds real behavioral context: results span all connected mailboxes, are sorted newest first, and exclude deleted emails. It stops short of covering result caps or how the limit interacts with the ordering.

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 scope and ordering are front-loaded, then the operator vocabulary is packed into one semicolon-delimited sentence with no filler. Every clause conveys information an agent needs to build a query.

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?

An output schema exists and annotations cover the safety profile, so the description only needs to carry search syntax and scope, which it does well. The single gap is the undocumented limit parameter for what is otherwise a complete two-parameter read tool.

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 0%, so the description carries the burden: it thoroughly documents the query parameter, including every operator and the free-text fallback, which is genuinely useful. The limit parameter is never mentioned, leaving its meaning (result cap, max 100) undocumented in both schema and description.

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 gives a specific verb (searches) and resource (emails across every connected mailbox), and names the fields matched (sender, subject, preview) plus the ordering (newest first). That scope statement effectively separates it from single-message siblings such as get_email.

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?

Usage is implied through the operator reference and the in:sent case, which tells the agent how to narrow a query. However, there is no explicit statement of when to reach for this tool versus get_email, list_to_answer, or other siblings, so the agent has to infer the routing.

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