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

The description adds valuable context beyond the annotations: it discloses that the operation 'meters one watch unit,' that free keys have limited concurrent watches, that exceeding the limit raises a 402 with the same semantics as the REST route, and that cancelling frees the slot. These are meaningful behavioral disclosures beyond the raw readOnly/idempotent hints.

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 compact and front-loaded: the primary action in the first sentence, a key constraint in the second, and important quota semantics in the last sentence. Every sentence earns its placer, with no verbose 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?

With no output schema and low parameter description coverage, the tool description needs to supply more missing operating context. It doesn't mention what the call returns, what constitutes valid event_types, how to obtain a webhook_endpoint_id (via register_webhook), or how idempotency interacts with the watch operation. This leaves material gaps for the agent.

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 only 20%, so the description carries the burden of explaining parameters. It explains webhook_endpoint_id's ownership constraint and the watch unit, but it does not clarify company_id, event_types, or why idempotency_key exists. An agent selecting the right event_types or crafting a correct idempotency request would not get enough help from this description.

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 and resource: 'Subscribe to a company's hiring events on a registered webhook.' This clearly identifies what the tool does and differentiates it from siblings like cancel_watch or list_watches by semantic context, though it never explicitly names those alternatives.

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 the use case (subscribing to hiring events) and includes prerequisites such as the webhook_endpoint_id belonging to the same customer as the authenticated key, plus quota behavior for free keys. However, it gives no explicit guidance on when to prefer this over siblings like find_company or is_hiring, or any when-not conditions.

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