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

The description successfully adds critical behavioral context that is not in the annotations, such as the complete list of 20 portal names, the data points returned (price, photos, etc.), and the cost of failure (costs nothing). This adds significant operational transparency beyond the simple read-only hint.

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 very dense and long, but this is justified because every sentence conveys highly specific, non-redundant information necessary for the agent to interact with the complex, multi-source API correctly. It sacrifices brevity for density.

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 the complexity of integrating 20 different external APIs, the description is extremely complete. It covers data scope, required external knowledge (via list_sources), and economic behavior (credits), leaving no vital operational gaps.

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?

Although schema coverage is 100%, the description provides invaluable semantic context by listing all valid portal keys and grouping them by country. This helps the agent understand the structural requirements of the 'source' and 'location' parameters far beyond a simple enum list.

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 is maximally clear, defining the tool's function as searching live sale and rental listings across 20 specific property portals. It lists the types of data aggregated into the single response schema.

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 provides essential usage guidance by referencing the sibling tool 'list_sources' to instruct the AI agent on which location formats and portal-specific filters must be used. It also clearly outlines the cost structure (1 credit/listing).

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