Get eSIM plan details

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

Annotations declare readOnlyHint and idempotentHint true; the description reinforces this by stating 'Nothing here reserves, orders or charges anything'. It also adds context about no login required and a price tax caveat, going beyond the annotations without contradicting them.

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?

Organized with purpose, WHEN, and AFTER SUCCESS sections. Front-loaded with the main action and every sentence adds useful operational or behavioral information without fluff.

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?

With an output schema present, return-value details are not needed. The description covers purpose, usage, parameter source, side-effect profile, and even a pricing nuance, making it fully complete for this simple read tool.

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 the description's guidance for bundle_code largely repeats the schema's own description ('from a result you have already received; never invent'). It does not add significant meaning beyond what the schema already provides, so the 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?

Description states 'Read the full details of one plan' and lists the specific fields (data, validity, price, coverage, plan type, activation policy, availability). This uses a specific verb (Read) and resource, and clearly distinguishes from sibling tools like browse/find by focusing on a single plan already listed.

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?

Explicitly provides a usage condition: 'WHEN: the user asks about a specific plan you already listed'. It instructs to pass the bundle_code from existing results and never invent one, and also states that this tool does not buy or reserve anything, guiding away from purchase use cases.

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