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

Annotations already establish readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely non-obvious behavior: results are cheapest-first and deduplicated to one plan per provider unless exactly one provider is given — a result-shaping rule the schema does not encode.

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?

A single dense sentence with no filler; the cheapest-first ordering — the most decision-relevant fact — is front-loaded alongside the filters.

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 an 11-parameter read-only search with full schema coverage, the description covers the essentials and notably explains the ordering/dedup behavior. With no output schema, it could say slightly more about what each result contains (price, provider, specs), but nothing critical to invocation is missing.

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 each of the 11 parameters carries its own units and examples (e.g. min_ram_gb '0.5 for 512 MB', location slugs). The description only loosely maps its four filter categories onto those parameters, adding little beyond the schema; 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+resource (search VPS plans) and adds the matching dimensions and sort order, which is more than a restatement of the title. It does not, however, distinguish itself from siblings like ask_vps_prices or current_vps_offers, which sound like they return overlapping pricing data.

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 by the filter vocabulary (size, budget, provider, location), so an agent can infer this is the filterable lookup tool. There is no explicit statement of when to prefer it over current_vps_offers or ask_vps_prices, and no exclusions or prerequisites.

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