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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the bar is lower. The description adds useful behavioral context beyond the annotations by mentioning cursor-based pagination, optional search, and the specific attributes returned, without contradicting any annotation.

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?

A single sentence with no filler. It front-loads the core action ('List inboxes'), then adds pagination/search behavior, then states the return fields. Every part earns its place.

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 simple, read-only list tool with an output schema and 100% schema coverage, nothing critical is missing. Safety is covered by annotations, parameter semantics by the schema, and return shape by the output schema; the description completes the picture with pagination and search behavior.

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 100%, and each parameter already has a clear description. The tool description adds only that search is 'free-text' and that pagination is cursor-based, which mirrors the schema. This meets the baseline but does not go beyond what the schema already communicates.

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 uses a specific verb and resource — 'List inboxes in the workspace' — and adds distinguishing details: cursor pagination, optional free-text search, and the returned fields. This clearly separates it from siblings like inbox_get, whose single-resource purpose is different, even without an explicit comparison.

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 clearly implies when this tool is appropriate: when a caller needs to enumerate inboxes, especially with search or pagination. It does not explicitly name alternatives or exclusion conditions, but the 'cursor pagination' and 'optional free-text search' phrasing gives enough context for an agent to choose it over inbox_get or email_list.

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