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

With no annotations, the description carries the transparency burden. It discloses two non-obvious behavioral traits: the site rejects datacenter traffic, so calls exit through a French residential IP driving a real browser, and requests are paid per call via x402. This is genuinely useful context beyond what any structured field would provide.

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 compact and front-loaded: the first sentence states the function and output, and the second adds essential operational context. There is no filler, and every sentence contributes to understanding the tool.

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?

This is a simple-looking tool with an important proxy behavior and no output schema, so the description needed to cover both invocation and results. It lists output fields, but the mismatch between the advertised budget/type filtering and the actual two-parameter schema is a serious gap. It also omits practical details like pagination, empty-result behavior, and rate limits, making the description insufficient for reliable invocation.

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 coverage is 0%, so the description needed to clarify city and cp, but it only vaguely groups them under 'location'. Worse, it advertises 'budget and type' as search dimensions that have no corresponding parameters in the schema, leaving the agent unable to actually express those constraints.

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 names a specific resource and action: 'Search SeLoger property listings', and lists the returned fields, which clearly distinguishes it from property-adjacent siblings like fr_leboncoin and fr_immo. However, it claims filtering by 'budget and type' even though the schema only accepts city and cp, so the stated purpose is broader than the actual input surface.

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?

No guidance is given on when to choose this tool over alternatives such as fr_immo, fr_leboncoin, or fr_estimation-immo. The description implies use for SeLoger listings, but it never states exclusions, precedence, or a decision rule.

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