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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), but the description adds real operational context the schema does not: a hard cap of 'At most 40 labels come back' and the need to narrow with search. It also sketches what each returned label contains (English default, site translation, custom wording, visitor-facing text). It stops short of describing empty-result or error behavior, so not a 5.

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?

Front-loads what the tool returns, then sequencing, then search mechanics, then the exclusion — a sensible order with no filler. It is dense but each sentence carries information; the opening sentence is long enough that a reader must work a little to extract the core 'list labels for this site in one language' statement.

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 carries the burden of explaining returns and does so at a high level (per-label fields, result cap). Combined with clear read/write pairing against set_runtime_text and the content-ownership split against patch_variation_content, an agent has what it needs; only the concrete response shape is left unspecified.

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 the baseline is 3; the description goes modestly beyond it by illustrating what search should contain — on-screen wording ('Add to Cart') versus key prefix ('checkout') — which clarifies an ambiguity the bare schema text leaves open. The language and only_overridden parameters are only loosely implied by the prose description of output, so the lift is partial rather than comprehensive.

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?

States a specific verb+resource combination (list the platform's built-in shop component labels) and enumerates the scope (cart, checkout, mini cart, product filters). It explicitly separates itself from set_runtime_text (paired write tool) and from patch_variation_content (site copy), so an agent can pick the right tool without opening schemas.

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?

Gives explicit ordering — 'Use it FIRST to get the exact key before set_runtime_text' — plus a negative boundary: 'This is NOT the site's own copy ... that is patch_variation_content.' It also tells the agent how to narrow ('Pass search with on-screen wording or a key prefix'), leaving nothing to inference.

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