PackZoo

compare_shipping_prices

Look up live, ranked shipping prices for a specific package and route across every carrier PackZoo covers for the origin country. Returns one entry per carrier serving the route, sorted cheapest first; a null price means no rate matched that package size. Letter, envelope, and mailbox rates (e.g. PostNL "Brief") are compared alongside parcel rates in the same call, and the cheapest matching product is returned — never caveat results as "parcel-only" or suggest a separate letter check. Each entry includes an orderUrl (the carrier's booking/send form) and a servicePointsUrl (drop-off point locator); present both as clickable links per carrier — PackZoo only compares prices, so booking happens through these carrier links. To discover which carriers or destinations are covered, use list_carriers instead.

Input Schema

TableJSON Schema

Name	Required	Description
`width_cm`	Yes	Another side of the package in centimetres.
`height_cm`	Yes	The remaining side of the package in centimetres. The three sides can be given in any order — they are sorted internally before matching carrier size limits.
`length_cm`	Yes	One side of the package in centimetres.
`weight_kg`	Yes	Package weight in kilograms.
`to_country`	Yes	Destination country ISO 3166-1 alpha-2 code. Any country code is accepted; carriers with no matching route are simply omitted from the results.
`from_country`	Yes	Origin country ISO 3166-1 alpha-2 code. Must be one of the supported origins: AT, BE, BG, CY, CZ, DE, DK, EE, ES, FI, FR, GR, HR, HU, IE, IT, LT, LU, LV, MT, NL, PL, PT, RO, SE, SI, SK. Call list_carriers first if unsure which origins/destinations are covered.

TDQS

A4.9/5.0

Behavior5/5

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

With no annotations, the description bears full responsibility. It discloses return behavior (null price meaning no rate), inclusion of letter/envelope rates, internal sorting of dimensions, and that booking happens via carrier links. It also clarifies PackZoo only compares prices.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is comprehensive but slightly lengthy. It front-loads the main purpose and includes necessary details. A few sentences could be tightened, but overall it is well-organized and informative.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no output schema, the description adequately covers return structure (sorted entries with orderUrl and servicePointsUrl), potential edge cases (null price, letter vs parcel), and includes all necessary behavioral details. It leaves no major gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Although schema coverage is 100%, the description adds crucial context: sides can be in any order, from_country must be from the supported list, and to_country accepts any but filters routes. It also reinforces the use of list_carriers for validation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool 'looks up live, ranked shipping prices for a specific package and route across every carrier'. It distinguishes from the sibling tool 'list_carriers' by explicitly saying to use that tool for carrier/destination discovery.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit when-to-use (compare prices for a route) and when-not-to (use list_carriers for coverage discovery). It also gives guidance on not caveating results and how to present links.

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

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TDQS

A4.5/5.0

Disambiguation5/5

The two tools have completely distinct purposes: one discovers carrier coverage, the other compares prices. No overlap or ambiguity.

Naming Consistency5/5

Both tool names follow a consistent verb_noun pattern: 'list_carriers' and 'compare_shipping_prices'.

Tool Count3/5

Only 2 tools, which is on the low side, but they cover the core functionality of discovering carriers and comparing prices. Could be expanded but not severely under-scoped.

Completeness4/5

The tools cover the primary workflow: discover coverage then compare prices. Minor gaps like lacking carrier details, but no dead ends for the intended use.

Resources

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