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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is fully covered. The description adds value beyond them by disclosing the shape of the result — the full company list plus which one the connection is currently working with — which the agent could not know from annotations alone. It stops short of noting ordering or pagination, but with zero params and a read-only list that is minor.

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?

A single well-formed sentence with zero filler, and the key fact (list all companies, including the active one) is front-loaded. Nothing could be removed without losing information.

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 input parameters, no output schema, and annotations carrying the full safety profile, the description supplies exactly what is missing: what comes back (all reachable companies and the active one). Nothing an agent needs in order to call it correctly is absent.

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?

The tool takes zero parameters, so the baseline is 4 — there is nothing for the description to disambiguate. No schema semantics are missing or contradicted.

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 verb 'List' plus resource 'every company this connection reaches' is specific, and it distinguishes itself from get_connected_company by covering the full set rather than one company. It also notes it returns which company is currently active, though 'this connection' is a slightly abstract framing an agent must infer means the authenticated Fortnox integration.

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 is implied by the plural 'every company' versus the singular get_connected_company sibling, but no alternative is named and no condition or prerequisite is stated. An agent can reasonably infer when to reach for it, but it is left to inference rather than explained.

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