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Glama

easypost

by io.usefulapi

Buy a shipping label

easypost_buy_shipment
Destructive

PURCHASE a shipping label for a shipment at a chosen rate. WARNING: this CHARGES the EasyPost account balance and is irreversible except by requesting a refund (easypost_refund_shipment). Pick a rate_id from the rates returned by easypost_create_shipment or easypost_get_shipment. API: POST /shipments/{id}/buy (body { rate: { id }, insurance? }).

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
rate_idYesRate id to purchase (from create_shipment / get_shipment rates).
insuranceNoDollar amount to insure the shipment for, e.g. "249.99".
shipment_idYesShipment id to buy, e.g. shp_...

TDQS

A4.1/5.0
Behavior4/5

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

Annotations already indicate destructiveHint=true. Description adds that it charges account balance and is irreversible except via refund. This goes beyond annotations by specifying financial impact.

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

Conciseness5/5

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

Three efficient sentences. Front-loaded with purpose and warning, followed by usage instruction and API detail. No wasted words.

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

Completeness3/5

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

No output schema, but description doesn't mention return value. For a purchase tool, a typical response (e.g., label object) is not described. Adequate but could be improved.

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

Parameters3/5

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

Schema has 100% coverage with descriptions for each parameter. Description adds context for rate_id (source) and insurance (example format), but adds limited value beyond schema.

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?

Clearly states it purchases a shipping label using a chosen rate. Verb 'PURCHASE' and resource 'shipping label' are specific. Differentiates from sibling tools like easypost_create_shipment (creates shipment without purchase) and easypost_refund_shipment (refund).

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

Usage Guidelines4/5

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

Explicitly tells when to use: after getting rates from easypost_create_shipment or easypost_get_shipment. Mentions alternative for refunds. Does not explicitly state when not to use, but context is clear.

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

A4.1/5.0
Disambiguation5/5

Each tool has a distinct purpose: address operations, shipment lifecycle (create, buy, refund, get, list), and tracking. No overlap or ambiguity.

Naming Consistency5/5

All tools follow a consistent `easypost_<verb>_<resource>` pattern using snake_case, with clear verbs like create, get, list, buy, refund, verify.

Tool Count5/5

11 tools cover the essential operations for address management, shipment lifecycle, and tracking without being too many or too few.

Completeness4/5

Core workflows (rate, buy, refund, track, address verification) are complete. Minor gaps like missing delete for addresses or update for shipments are acceptable for the domain.

Resources