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

Beyond the readOnlyHint and destructiveHint annotations, the description discloses key backend behavior: the first 8 characters are extracted automatically, the rest is ignored, any length between 8 and 33 is accepted, and NOT_FOUND means the value is not an Austrian operator. This substantially clarifies expected runtime behavior and error 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 dense and front-loads the most important behavioral constraint (only reactive use). There is some repetition around the 8/33-character rule and the warning not to reject values, but the emphasis is arguably intentional to prevent a costly agent error. It remains appropriately sized for the guardrails it communicates.

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?

The description fully covers the tool's trigger condition, input handling, output examples, and NOT_FOUND interpretation. Given the simple single-parameter schema, output schema, and safety annotations, nothing essential is missing for an agent to invoke this tool 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 schema already documents min/max length and the instruction not to insist on exactly 8 or 33 characters. The description adds crucial semantics: pass the user's value through unchanged, do not reject based on length, and know that the backend handles extraction. This goes well beyond the structured schema.

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 the tool's function: it returns the Austrian network operator name for a given Zählpunktbezeichnung (e.g. AT001000 → Wiener Netze). This is a specific lookup operation with a distinct resource, and it is easily distinguishable from the sibling tools, which handle tariffs, quotes, requirements, and articles.

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 gives explicit when-to-use and when-not-to-use guidance: only use when the user voluntarily and unsolicited provides their Zählpunktbezeichnung, and never proactively ask for this field. It also specifies exact handling of NOT_FOUND results, telling the agent to communicate that the value does not belong to any Austrian network operator rather than being vague.

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