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

The annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds return-content context by enumerating the included fields, which is valuable given there is no output schema, but it says nothing about error behavior or what happens for missing/archived contacts.

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 efficient sentence-fragment with zero padding, front-loading the resource and its payload. It loses a point only for being a fragment rather than a complete, scannable statement of purpose.

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 simple single-item read with annotations covering safety and a fully documented two-parameter schema, the description adequately fills the one gap – return contents – since no output schema exists. Slightly more (e.g., behavior for archived contacts) would make it complete.

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 the schema already explains contact_id ('from bexio_list_contacts') and archived. The description adds no parameter-level detail, so the baseline 3 for fully documented schemas 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 names the resource ('One contact') and enumerates the returned fields (address, emails, phones, language, groups, remarks), so the intent is inferrable. However, it is a noun phrase fragment with no explicit verb and does not explicitly contrast with bexio_list_contacts, leaving the single-vs-many distinction implicit.

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 guidance on when to use this tool versus bexio_list_contacts or other get tools, and no prerequisites or exclusions are stated. The agent must infer usage entirely from the name and the plural sibling.

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