subscribe_invoice_status_by_hash

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'Subscribe to real-time updates' without explaining how updates are delivered (e.g., webhook, websocket), whether the subscription is long-lived or requires cancellation, or what the response looks like. This is insufficient for a subscription tool.

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?

The description is a single, concise sentence that is front-loaded with the core purpose. It contains no redundant or extraneous information, making it efficient and easy to parse.

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?

Given the absence of annotations and output schema, and the existence of a very similar sibling tool (subscribe_invoice_status), the description is too sparse. It does not clarify delivery mechanisms, subscription lifecycle, or how to disambiguate from similar tools, leaving critical context missing.

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 provides 100% coverage of the single parameter with a clear description ('The payment hash to monitor'). The tool description adds no additional semantic detail beyond what the schema already states, so a baseline score of 3 is 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?

The description clearly states the action ('Subscribe to real-time updates') and the resource ('Lightning invoice by payment hash'). It differentiates from sibling tools like subscribe_invoice_status by explicitly specifying the hash-based subscription, making the purpose unambiguous.

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 implies usage for monitoring invoice status via payment hash, but does not explicitly state when to choose this over the similar sibling tool subscribe_invoice_status, nor does it mention any prerequisites or exclusions. It provides no direct guidance for selecting this tool among alternatives.

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