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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so safety is covered. The description goes further and discloses the return shape (each hit exposes invoice_fields = {customer_name, customer_orgnr, customer_address}), which is critical because there is no output schema, plus the exact-match behavior for 10-digit input.

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?

Dense but front-loaded: search behavior first, then the integration use case, then arguments. Every clause carries information, though the single long sentence packs the downstream-tool instructions tightly enough that it is slightly less scannable.

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 two-parameter read-only search with no output schema, the description covers purpose, usage flow, parameter ranges, and the returned field structure. Nothing an agent needs in order to call it and consume the result is missing.

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 0%, so the description must carry the load: it explains that query accepts a name or an organisationsnummer (10 digits = exact hit) and documents limit's range (1-10) and default (5), neither of which appears in the schema's min/max. Minor gap: no format guidance (e.g. hyphenated org numbers).

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 ('Sök ett svenskt bolag i Bolagsverkets register') plus the two search modes (name or org number, with the 10-digit exact-hit nuance). This is clearly distinguishable from siblings like list_companies (enumeration) and get_company (single-fetch), even without naming them.

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 an explicit, actionable use case: look up the company to populate name, org.nr and address before create_customer_invoice or create_supplier_invoice. It routes the agent to the downstream tools well but does not state when *not* to use it (e.g. for the agent's own company record).

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