Get Contact Info

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

With no annotations, the description carries the burden and does add behavioral context: it lists the returned fields and discloses a key limitation (groups are not supported). It stops short of describing error behavior, nullability, or permission requirements, but for a simple read-only getter the description is reasonably transparent.

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?

Two short sentences with no filler. The output fields are front-loaded, followed immediately by the essential limitation and sibling alternative.

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 one-parameter getter with no output schema or annotations, the description covers the main return values and the principal usage boundary. It does not mention failure modes or whether fields can be null, but the overall call context is simple enough that the gaps are minor.

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 0%, so the description must compensate. It only indirectly defines chat_id by stating that groups do not work, implying chat_id should identify an individual contact; it does not explain the format or give examples. Some meaning is added, but the sole required parameter is not fully documented.

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 specifies the tool's resource and output: a contact card containing name, avatar, business-account flag, and last online. It also explicitly distinguishes itself from get_group_data by stating groups are not supported, so an agent can reliably select it for individual contacts.

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?

It gives an explicit exclusion and routing rule: 'Для групп не работает — используйте get_group_data' (does not work for groups — use get_group_data). This clearly tells the agent when not to use this tool and names the alternative sibling directly.

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