Find cheapest ads

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

Beyond the readOnly/idempotent annotations, it discloses real behavior: negotiable, placeholder and absurd prices are skipped, sub-10%-of-median ads are dropped unless `include_outliers` is set, rent categories rank on monthly rent, and the response reports how many ads were scanned and skipped. That is exactly the kind of context annotations cannot convey.

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?

Front-loaded with the result shape and ranking rule, then caveats and next steps. It is dense rather than bloated, though the outlier behavior is stated twice (in prose and again against `include_outliers`), which is minor redundancy.

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 17-parameter, no-output-schema tool this is close to complete: it explains the scan model, exclusions, ranking, and what the answer reports. It omits only edge behavior such as what a fully unfiltered scan returns, which the agent can infer from the parameter docs.

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 100%, so baseline is 3, but the description adds meaning to specific params: `pages` (~25 ads per page, affects scan width), `include_outliers` (sub-10%-median ads), and the rent-category interpretation of min/max price. It adds value over the schema without documenting every one of the 17 parameters.

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 verb and resource ('the cheapest ads of a search, cheapest first') plus the exact scope of the scan, which cleanly separates it from siblings like dv_search, dv_best_for_budget and dv_find_deals. An agent can tell what this tool returns without opening the 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 gives concrete operating guidance: raise `pages` for a wider scan or narrow with `filters`, and it names follow-on tools (dv_post, dv_compare). It does not explicitly say when to prefer a sibling such as dv_best_for_budget over this one, so it stops short of full when/when-not coverage.

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