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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's extra value is provenance and completeness: it is computed server-side from live Fortnox data over all pages, meaning results are aggregated across pagination and not stale cache. It also clarifies that the output is proposals to approve rather than performed writes, which reinforces readOnly semantics rather than contradicting them.

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 tightly packed sentences: purpose first, then example trigger, then data provenance. The Fortnox API URL is marginal but serves as source attribution; nothing meaningful is buried.

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 an output schema present, return values need no prose, annotations carry safety, and the schema fully documents the optional parameters. The description supplies exactly the missing layer — what business question the package answers and where the numbers come from.

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% and all four parameters (ar, date, serie, financialyear) are documented in the schema, including defaults, so the description need not repeat them. It adds no guidance on the interaction between ar and date or on what serie affects, 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?

The description enumerates the concrete deliverables (remaining year-end steps, estimated tax, periodiseringsfond, ready-to-approve year-end voucher proposals) and frames it as a K2 year-end package. That is far more specific than the noun-only name, but it never distinguishes it from nearby siblings such as get_month_end_review, get_balance_sheet, or check_accruals, which an agent may see as overlapping.

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 example question "Förbered bokslutet för 2025" implies the trigger scenario, but there is no explicit when-not guidance or named alternative for month-end vs year-end work. Usage is inferable rather than stated.

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