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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuine value beyond them by enumerating what a call returns (buyer organisation, publication date, CPV codes, procurement project id, national/framework/DPS flags), though it says nothing about auth requirements or behavior when a notice is not found.

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?

Two tight sentences: the first front-loads the action and identifier, the second enumerates the returned metadata. No filler, no repetition of the tool title.

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 return-value burden and does so well by naming the metadata fields an agent can expect. Inputs, source, and output shape are all covered; only edge behavior (not-found, missing/invalid api key) is absent, which is a minor gap for a read-only lookup.

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%, so both 'id' and 'notice_number' are already documented in the schema, including the 'provide this or...' mutual-exclusion wording. The description restates the identifier formats (e.g. "2026-012345") without adding syntax rules, validation, or precedence guidance beyond what the schema provides. 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?

States a specific verb and resource (look up a single Finnish public procurement notice on Hilma) and pins the lookup key (Hilma notice number or index document id). The word 'single' plus the identifier-based retrieval implicitly separates it from the list-oriented siblings hilma_search and hilma_recent, but neither sibling is named explicitly, so differentiation is left partly to inference.

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?

The description implies the use case — resolving one known notice by identifier — but never states when to reach for this instead of hilma_search or hilma_recent, nor any precondition (e.g. that the id comes from a prior search result, which only appears in the schema). Usage is inferred rather than taught.

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