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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains that the tool is not a functional operation but a signal that the catalog is down, that no portal tools are available, and that the exact cause is in the server's stderr. It also discloses the expected fallback behavior (informing the requester) and explicitly forbids bypass attempts. This fully discloses the tool's non-functional nature and the reasoning behind it.

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 a single, dense paragraph that front-loads the core message (backend down, no tools available) and then provides corrective actions and prohibitions. Every sentence contributes essential information: the root cause, the implication, troubleshooting steps, and explicit instructions. There is no fluff or redundancy, making it both concise and structurally sound.

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?

Given that there is no output schema and the tool is essentially a status indicator, the description is complete. It specifies what happened, why, what to check, what not to do, and what to tell the requester. All necessary operational context is provided, and because the tool has zero parameters and no output expectations, the description fully covers what an agent needs to handle this situation correctly.

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 input schema is empty with 0 parameters, so the baseline is 4. The description does not need to add parameter details, but it explains why the tool takes no arguments (it is a placeholder for an unavailable catalog). It also provides environment variable checks (FUNILARIA_API_URL, FUNILARIA_SERVICE_SECRET) as context, which indirectly explains the setup. This exceeds the baseline by giving operational context beyond the mere absence of parameters.

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 clearly states that the tool indicates the backend did not respond to GET /mcp/catalogo, making the entire portal's tools unavailable in this session. It does not use a classic verb+resource phrasing, but its purpose as an unavailability signal is unambiguous and distinct from any normal tool. Since there are no siblings, the distinguishing aspect is not relevant, but the description still clearly explains what it represents.

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 explicitly instructs when to use this tool (when it appears, treat it as a session-wide unavailability) and what NOT to do: do not attempt to fulfill the task by other means, do not craft HTTP requests manually, do not invent URLs or secrets. It also tells the agent to inform the requester. This is direct, actionable context with explicit exclusions, covering both usage and alternatives.

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