list_open_messages

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

With no annotations, the description carries the burden. It discloses the state filter (unhandled), the returned fields, and a prerequisite (webhook running/subscribed). It does not mention sorting or error behavior, but for a simple read-only list tool this is sufficient context.

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 sentences, front-loaded with the main purpose, then a useful detail about returned fields and thread_id, then a prerequisite and a cross-reference. Every sentence earns its place with no filler.

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 tool with one optional parameter and an output schema, the description fully covers what it does, what it returns, why it exists, and what must be true before calling it. The prerequisite and the thread_id usage hint make it complete in context.

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 description coverage is 0%. The only parameter, limit, is completely absent from the description. The description does not add any meaning such as 'maximum number of messages to return' or clarify default behavior beyond the schema's default value of 50.

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 ('List') with a clearly bounded resource ('inbound guest messages... that haven't been marked handled yet'). It establishes the tool as the 'open messages inbox,' which clearly distinguishes it from sibling list_messages.

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 gives a clear context (open messages inbox) and explicitly states a prerequisite: the webhook receiver must be running and subscribed, with a pointer to create_webhook_subscription. It does not explicitly name alternative tools for when the user wants all messages, but it defines the relevant filter.

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