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

Annotations already declare readOnlyHint=true, so safety is covered, but the description adds real behavioral context beyond that: exact-word matching with no stemming, best-match ordering, and the notable exclusion of messages held by the security scan. It does not describe pagination or how the limit interacts with results.

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?

Three tight sentences, front-loaded with the action and scope, then usage, then matching/exclusion caveats. No filler, every clause carries information.

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?

With an output schema present, return values need not be described, and the description covers scope, usage, matching behavior, and exclusions. The remaining gap is limit/pagination behavior and a fuller statement of inboxId requirements.

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 only 33% (only q is documented). The description partially compensates by clarifying that 'one inbox' scopes results (inboxId semantics) and that matching is exact/no-stemming, which adds value for q. However, limit and its 1-50 bound are left entirely to the schema.

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 ('Full-text search one inbox's mail') with the searched fields enumerated (subject, sender, reply text) and result ordering ('best match first'). This clearly distinguishes it from siblings like volanea_read_inbox and volanea_wait_for_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?

Gives explicit when-to-use contexts: finding an earlier conversation before replying, or checking whether something already arrived. It does not name alternative tools (read_inbox, wait_for_email) or state when not to use it, so it stops short of a 5.

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