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

Annotations cover the safety profile (destructiveHint=false, idempotentHint=true), but the description adds context annotations cannot express: the side effect that the year's periods are opened for booking, the required 'book' permission, and the returned lock status. This is meaningful disclosure for a state-changing operation, though it doesn't address concurrent-lock or audit-trail implications.

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?

The core action and its purpose come first, followed by the usage restriction and alternatives, then side effects and permissions. Every sentence carries distinct information with no repetition of the name or 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 compensates by stating what is returned ('Returnerar årets låsstatus'), and it covers the side effect, the permission requirement, and the alternatives. An agent has everything needed to decide and invoke correctly.

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% – both orgnr and year are fully documented in the schema, including the fiscal-year-end convention. The description adds no parameter-level meaning beyond that, so the 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 ('Låser upp ett räkenskapsår igen, alla dess månader') plus the goal ('så att rättelser kan bokföras'). It distinguishes itself from siblings by name, explicitly calling out reverse_voucher as the lighter alternative and lock_fiscal_year as the inverse operation.

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 when-to-use condition ('Använd bara när användaren uttryckligen vill rätta i ett låst år'), names a preferred alternative for the common case (reverse_voucher in an open period), and routes to the complementary tool for re-locking (lock_fiscal_year). Nothing is left to inference.

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