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

Beyond the annotations, the description adds meaningful behavioral context: the data is cached, a read:inbox permission is required, and the call is free with no changes. It does not describe pagination behavior or return shape, but the annotations already cover safety and idempotency.

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 short sentences, front-loaded with the core purpose and the critical cache distinction. Every sentence adds useful information without repetition.

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 inbox cache tool with complete schema descriptions and rich annotations, the description provides enough context to invoke it correctly. The main omission is not naming the live-inbox alternative, but the essential usage and behavioral constraints are covered.

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%, so limit and cursor are already documented in the schema. The description adds no additional parameter semantics beyond the schema, which is acceptable at baseline when the schema does the heavy lifting.

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 names a specific verb and resource: reading the app's saved inbox, including snooze and done state. It clearly distinguishes this as a cached read rather than a live refresh, though it does not name the live-inbox sibling directly.

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?

It gives clear usage context by stating that this is a cache and not a live refresh, which helps an agent decide when cached inbox data is appropriate. However, it does not explicitly name an alternative live-inbox tool or state exclusion conditions.

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