search_emails

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

Annotations only declare readOnlyHint and openWorldHint, but the description adds real behavioral context: whole-word matching by default, dates interpreted as local calendar days keyed to the sent date, results ordered newest first, and the side-effect guarantee that emails are not marked read. It omits anything about result-set size/pagination or the shape of a match, which keeps it short of a 5.

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?

Four short sentences, front-loaded with the searchable fields and continuing into match semantics, date semantics, ordering, and side effects. Every sentence adds information and none is padding.

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 an 8-parameter, output-schema-less search tool with read-only annotations, the description covers matching rules, date interpretation, ordering, and the crucial non-mutation guarantee. It leaves result payload/pagination and the meaning of count's interaction with matches unstated, so it is strong but not fully closed.

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, but the description adds semantics the schema does not: that dates are local calendar days anchored on the send date, and the consequences of whole-word matching ('bill' does not match 'billion'). Those clarifications materially change how since/before/query/wholeWord should be set.

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?

States a specific verb and resource plus the searchable fields ('Search emails by text (subject, sender, and body), sender, and date range'), which is far more than a tautology. It does not, however, name or distinguish itself from the sibling list_emails, so the agent must infer the split.

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 by the filter vocabulary (use this when you want to match text/sender/dates), but there is no explicit when-to-use, no when-not-to-use, and no mention of list_emails as the unfiltered alternative. The agent is left to infer routing from the filter set alone.

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