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

Beyond the readOnly/openWorld annotations, it discloses latency characteristics ('a few seconds' vs 'typically 15–25 seconds') and that a short explanation is returned. This is genuine operational context an agent could not infer from annotations. It stops short of describing failure behavior for unmatchable descriptions.

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 compact sentences: output shape first, return value second, latency last. Each sentence carries distinct information and nothing is redundant with the schema.

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 describing the return value and does so ('base term, facet descriptors ... labelled free text', plus an explanation), and it covers timing for a slow tool. An agent knows what to send, what comes back, and what to expect on latency.

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, but the description adds real meaning: one description only, English, covering food/drink/dish/meal, and that stated attributes not implied by the base term become facets. That clarifies what content the single string should carry.

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 precise verb+resource transformation ('Turn one English food description ... into a FoodEx2 code from the EFSA MTX catalogue') and even names the output composition (base term, facets, free text). The only sibling, account_status, is unrelated, so there is no ambiguity to resolve.

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?

Makes clear the input is a single English food description (food, drink, dish or meal), which implicitly excludes non-food or multi-item inputs. It gives no explicit when-not-to-use or alternative path, but with only an unrelated sibling there is little to route against.

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