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

With no annotations, the description carries the full behavioral burden. It does useful work by disclosing that budget_eur_month accepts null meaning 'no limit' and by spelling out the open_policy enum meanings, but it never says whether unspecified fields are left untouched (partial update) or reset, whether changes require elevated auth, or whether webhook_url is validated on write.

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?

One densely packed sentence with no filler, front-loading the concrete field names and their meanings. Nothing is redundant with the schema except the enum value list, which is minor.

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 9-parameter mutation tool with no annotations, no output schema, and 11% schema coverage, the description leaves major gaps: partial-update semantics, auth requirements, side effects of setting a webhook, and the role of the purpose parameter are all unaddressed. An agent could call it but would be guessing about update behavior.

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 only 11%, so the description must compensate, and it partially does: budget_eur_month's null semantics and address_name's meaning are genuine additions. However, auto_reveal_codes is named with zero explanation, webhook_url gets no format or behavior detail, and purpose and api_key are not addressed at all, leaving several of nine parameters semantically thin.

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 opens with a clear verb ('Set') and enumerates the specific account fields that can be changed, so an agent knows this is a settings-mutation tool rather than a read. It never names the resource ('account') explicitly, relying on the tool name and title to carry that, and it doesn't contrast itself with siblings like get_account, but the field list makes the scope concrete.

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?

There is no statement of when to use this versus alternatives: no mention that get_account reads current values, no guidance on operator_name/operator_email versus the contact_human sibling, and no prerequisites. The agent must infer usage entirely from the field list.

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