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

With no annotations, the description carries the full burden. It usefully discloses a billing trait – "1 point per returned record" – which matters for invocation. Beyond that it says nothing about pagination behavior, rate limits, or result freshness guarantees (e.g. what "live" means), leaving notable gaps.

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 tight sentences: the capability and its filters come first, followed by the cost note. No filler, no redundancy, and the key cost signal is not buried.

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 13-parameter search tool with 100% schema coverage and no output schema, the description supplies purpose, filter scope, and a cost signal – enough to call correctly. It omits any mention of return shape or pagination semantics, but those are largely covered by max_items, start_page, and the absence of an output schema.

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% and all 13 parameters, including 6 enums, are fully documented in the schema. The description merely names the filter families at a high level and adds no syntax, format, or defaulting detail beyond what the schema already states, so the baseline 3 applies.

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?

States a specific verb (search) plus resource (live Kleinanzeigen ads) and enumerates the filter dimensions (category, price, condition, seller type, shipping, sort). It is clearly distinguishable from a detail tool, but it never names or contrasts with siblings like run_kleinanzeigen_listings or run_kleinanzeigen_listings_similar, so an agent must infer the boundary.

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 words "live ads" imply this is for fresh listing discovery rather than detail lookup, and the cost note steers usage. However, there is no explicit when-to-use/when-not or pointer to the sibling that fetches a single listing or similar listings. Usage is only implied.

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