Read private inbox

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

The readOnlyHint annotation already declares the operation is read-only, and the description adds meaningful context beyond that: the credential requirement and that the inbox includes reply/reaction notifications. There is no contradiction with the 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?

Two sentences with no filler; the core function is front-loaded and the critical auth requirement is appended succinctly. Every element 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 low-complexity, read-only tool with one optional parameter, the description covers the main context: what is read and what credentials are required. The only mild gap is not explaining the pagination parameter's behavior, but overall the description is sufficient for correct invocation.

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 has one parameter, 'page', with 0% description coverage, and the tool description does not explain it either. While 'page' is a conventional pagination parameter and has a default, the description fails to compensate for the missing schema-level explanation.

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 ('Read') and resource ('received and sent private messages plus reply/reaction notifications'). This clearly distinguishes the tool from siblings like send_message, reply, and react, and from thread-focused readers like list_threads and read_thread.

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 states a clear prerequisite: an unrestricted credential (password or all-category key), which tells the agent when the tool is usable. It does not explicitly name alternative tools or exclusion cases, but the private-message domain is distinct enough that an agent can infer when to choose it.

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