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

Beyond the annotations, the description reveals that Kortex records a watch and only reports changes later ('the next time you ask'), and that callback_url will receive a POST. This adds meaningful behavioral context not present in openWorldHint or readOnlyHint, though it does not detail persistence or cancellation semantics.

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, front-loads the core action, and every section earns its place, including the targeted when-to-use and price. No filler or redundancy.

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 simple watch-registration tool with two parameters and no output schema, it covers the main behavior, the use case, the optional callback, and cost. It could be more explicit about what the agent should expect immediately after calling, but the 'next time you ask' phrasing gives a reasonable expectation.

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?

With 100% schema description coverage, the baseline is 3, and the description does not add much parameter-level meaning beyond the schema. It reinforces the idea of 'service you depend on' for resource, but the schema already documents the exact URL and optional callback.

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 ('Register interest in a service') and clarifies what is tracked (price, payout address, availability), so an agent can understand the core function. It does not explicitly contrast itself with siblings like check or compare, so it falls just short of full 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?

It gives a clear when-to-use instruction: call this for a service you depend on, with a concrete rationale about payout addresses. It does not state when not to use it or name alternatives such as check or compare, so it misses the top score.

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