create_push_subscription

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

With no annotations, the description carries the behavioral burden, and it does well: it discloses that MockPost retains the private key, that the backend can send encrypted push via pywebpush or web-push, and that VAPID verification, decryption, and cleartext capture occur. It does not describe persistence or cleanup behavior, but for a zero-parameter mock helper this is strong disclosure.

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?

Two sentences, front-loaded with the core action and return shape, followed by the essential workflow behavior. Every clause adds value and nothing is redundant or padded.

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 no parameters, no annotations, and no output schema, the description is complete: it states exactly what is returned, how the result should be used, and what happens when the backend delivers a push. An agent has enough information to invoke it correctly and integrate it into a test flow.

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?

There are zero parameters and 100% schema coverage, so the rubric baseline is 4. The description adds no parameter-level meaning because none exists, and none is needed.

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 opens with a specific action ('Create a Web Push subscription') and precisely defines the return shape as the browser's PushSubscription with endpoint and p256dh/auth keys. This clearly distinguishes the tool from siblings that list, expire, or simulate push-related events.

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 clear usage context: 'Hand it to the app under test' and explains how the subscription is used when the backend sends an encrypted push. It does not explicitly enumerate when-not-to-use or name alternative tools, but the intended workflow is unmistakable.

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