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

With no annotations, the description carries the full burden, and it does establish the key trait: this is a non-mutating check against the HN session cookie, implicitly read-only. However it says nothing about what a positive/negative result looks like or whether the check is local vs a network round-trip.

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?

One sentence, front-loaded with the verb and the resource, with zero filler. Nothing could be removed without losing information.

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?

No annotations and no output schema, yet the description never indicates the shape of the answer (boolean, status string, expiry info), which is the single most important thing an agent needs from a status tool. Adequate on what it checks, silent on what it returns.

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 the single notification_message parameter is fully documented in the schema and the baseline of 3 applies. The description adds no meaning about when that message is surfaced or why a status check needs a failure message.

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?

A specific verb ('Check') and a well-defined resource (presence/validity of hn_session_cookie on Hacker News) make the tool's job unambiguous. It doesn't explicitly name the sibling it differs from (login), so it stops short of full sibling differentiation.

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 never states when to call this versus login, or what to do with a negative result. Usage is only implied by the concept of checking session state, leaving the agent to infer the routing.

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