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

Annotations already declare readOnlyHint=true, openWorldHint=false, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description still adds real context: it works unauthenticated, it does not inspect any store data, and the response is 'one line per match with a Shopify App Store install link'. The main uncorrected gap is behavior when nothing matches, which matters for a matching tool, though with full annotation coverage a 3 reflects value added without full disclosure.

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?

Three tight sentences: purpose with examples first, then access/side-effect constraints, then return shape. Every sentence carries new information and nothing is repeated.

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 no output schema, the description correctly compensates by describing the return as best match(es), one line each, with an install link. It also covers auth requirements and store-access scope. The only shortfall is not stating what happens on a miss (empty result vs. fallback suggestion), which an agent would want before deciding how to phrase the query.

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?

There is a single required parameter with 100% schema description coverage, so the schema already explains 'need' including the 'in their words' phrasing. The description adds only illustrative need examples, which largely duplicate the schema example. Baseline 3 is appropriate.

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?

The description states a specific verb and resource: 'Find which EA Shopify app fits what a merchant wants', and backs it with concrete need examples (sticky add to cart bar, bundles, email popup, translation, free shipping bar). It distinguishes itself from listing-style siblings implicitly through 'Returns the best match(es)', but never names list_ea_apps or list_apps, so the differentiation is inferable rather than explicit.

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 context is clear: call this when a merchant describes a capability they want and you need to map it to an EA app. 'Works without signing in' and 'Doesn't read any store' establish preconditions and scope boundaries. It stops short of naming the alternative (list_ea_apps) for the case where the agent just wants a catalog dump, so no explicit when-not routing.

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