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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, so the safety profile is covered. The only behavioral contribution is the word 'authorised', implying results are permission-scoped, with no mention of ordering, pagination, or what an inbox object contains (and there is no output schema to fill that gap).

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 words, no filler, purpose front-loaded. Brevity is a virtue here, though it borders on under-specification rather than tight editing.

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 two-parameter read tool with full schema coverage and annotations, this is minimally adequate. However, with no output schema, the description could have said what an inbox entry includes or how results are ordered, which would let an agent chain into list_messages confidently.

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?

The schema fully documents both parameters (limit with default/max, projectId as an optional filter) at 100% coverage, so the baseline is 3. The description adds no extra meaning about pagination behavior or what 'authorised' scoping means relative to projectId.

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?

A specific verb (List) plus resource (inboxes) with a scope qualifier ('authorised') that separates it from list_messages and list_projects by resource. It does not explicitly name a sibling or contrast with one, so it stops short of a 5.

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?

There is no guidance on when to call this versus list_messages, list_projects, or get_usage; nothing says it is the discovery step before list_messages. The agent must infer the workflow entirely from the resource name.

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