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

With no annotations, the description carries the full burden. It does disclose meaningful behavior: the counting semantics (only evaluated locations, not all supply areas) and that output includes a finished citation sentence. It does not state read-only nature, permission needs, or rate limits, so coverage is partial but not absent.

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 count behavior and followed by the scoping caveat. No redundant restatement of the tool name, and each sentence adds information.

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 two-optional-parameter query tool with no annotations and no output schema, the description adequately explains what is counted and that a citation sentence is returned. Remaining gaps (exact response shape, auth) are minor given the low complexity.

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?

Schema description coverage is 100%, so the schema already documents both optional parameters (state slug, substance key). The description reinforces their meaning ('Deutschland oder ein Bundesland', 'für einen Stoff') but adds no syntax or format detail beyond the schema, making the baseline 3 appropriate.

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 states a specific computation – counting how many evaluated locations report a value for a substance versus how many do not, plus a ready citation sentence. The resource (Prüfbericht values per substance, scoped to Germany or a Bundesland) is identifiable, though it does not explicitly contrast itself with siblings like get_water_quality.

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?

Usage is implied rather than stated: an agent can infer this is for assessing data coverage, and the constraint 'zählt nur ausgewertete Orte, nicht alle Versorgungsgebiete' clarifies scope. However, there is no explicit when-to-use versus alternatives such as get_water_quality or verify_claim.

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