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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered by structured data. The description adds that the response carries status, install steps and remaining data, plus that the id is an email-link token. It does not describe behavior on an invalid/expired token, whether the link token is sensitive, or the shape/format of the returned page data.

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 clause with the resource and returned fields front-loaded and no filler. It is a sentence fragment rather than a complete sentence, but nothing in it is redundant.

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 simple, annotation-rich, single-id read operation with no output schema, the description covers the essential elements: what is fetched, what comes back, and where the id originates. Only failure/edge-case behavior is left unstated, which is a minor gap at this complexity level.

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 both parameters are already documented in the schema, including that the id is the link token. The description restates the id's origin (e-mail link) without adding new syntax, format or validation detail; the optional "context" parameter is not addressed at all. Baseline 3 is appropriate when the schema does the heavy lifting.

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?

Names a specific resource ("the traveller's eSIM page") and enumerates what it yields (status, install steps, data left), so an agent knows this is a read of a single traveller's eSIM view. It does not name or contrast any sibling, but the sibling set (checkout, coverage_check, plans_list, quote_trip) is clearly disjoint from a per-eSIM page lookup, so confusion risk is low.

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?

"from the eSIM id in their e-mail link" implies the precondition for calling (you must already have the traveller's eSIM token), which is useful context. However, there is no explicit when-to-use/when-not guidance, no mention of what to do when the id is unavailable, and no pointer to an alternative tool.

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