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

Annotations only cover the safety profile (readOnlyHint, openWorldHint, idempotentHint); the description goes well beyond them with latency expectations (seconds on first call, minutes on first launch), the `starting: true` non-failure state with a ~30 second ready window, and the guarantee that it never raises an error but reports `connected: false` plus a message. These are exactly the behavioral traits an agent needs to avoid mis-handling startup.

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?

Information is front-loaded (what it does, then timing, then error semantics), and every sentence carries real content. The second sentence is long and stacks several clauses, which slightly hurts scannability, but nothing is redundant.

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 an output schema present, return values need not be described, yet the description still pre-empts the two states an agent will actually encounter (`starting: true`, `connected: false`). Combined with annotations covering safety and idempotency, an agent has everything needed to call and interpret this tool.

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 tool takes no parameters, so the baseline is 4. The description correctly adds no parameter noise; schema coverage is 100% and there is nothing further to document.

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 verb and resource: 'Check that the editing session is up.' That purpose is unique among the siblings, all of which are editing operations (crop, retouch, export_photo), so an agent can immediately tell this is the connectivity/session probe rather than a content mutation.

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 implies usage by explaining that the first call starts the session, which signals this should be called before dependent editing tools, but it never states that explicitly nor names what to do on `connected: false`. The guidance is inferable rather than stated.

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