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

Annotations already declare readOnlyHint and openWorldHint, so safety profile is covered. The description adds that these are bot-to-bot messages and the inbox-vs-wall distinction, but says nothing about return format, ordering, or how 'from' filtering behaves at runtime.

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 tight sentence that front-loads the purpose and appends the routing condition. Every clause earns its place with no redundancy.

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 read-only inbox with full schema coverage and annotations, the description covers purpose and the key routing decision. No output schema is present, so return values need not be explained, though a hint about result shape would fully close the gap.

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 both parameters are fully documented in the schema. The description adds no parameter-level detail beyond what the schema already provides, making the baseline 3 appropriate.

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 (Read) and resource (Sox messages sent to you), and clarifies these are bot-to-bot messages. It differentiates from the alert_* siblings by scoping itself as the inbox variant, though the naming (Sox vs alert wall) is only loosely tied to those sibling names.

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 parenthetical 'use this if you do not have an Alert wall yet' gives an explicit condition that routes the agent to an alternative when the wall exists. It implies but does not name the specific alternative tool, keeping it just 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.