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

The description discloses a key behavioral trait: contacts are gated behind the recruiter_context introduction, which is beyond what any annotation would provide. It also implies the tool returns sensitive contact data, adding important context for the agent. Since there are no annotations, the description carries the full burden and handles it well.

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 description is concise and front-loaded: it states what the tool returns first, then the prerequisite, and then the parameter caveat. Every sentence earns its place, and the bilingual format is efficient for the target audience.

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?

Given the tool's simplicity (one optional parameter, no output schema), the description covers the essential points: what it returns, the prerequisite, and the parameter semantics. The only minor gap is that it does not mention whether the output format varies by communication channel, but this is not necessary for a simple contact-lookup tool.

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%, so the baseline is 3. The description adds minimal parameter-specific explanation beyond the schema, but the schema itself already fully documents the candidate parameter, including the slug source and the optionality in personal mode. Thus, the description meets the baseline without needing to compensate.

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 clearly states the tool's function: 'Прямые контакты кандидата (телефон, email, мессенджеры)' (Direct contacts of the candidate: phone, email, messengers), using a specific verb and resource. It also adds a critical prerequisite: contacts are only provided after introducing yourself via recruiter_context, which clearly distinguishes this tool from others.

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 description explicitly states when to use this tool: after introducing yourself via recruiter_context. It also mentions the alternative context (personal mode) where the candidate parameter is optional. However, it does not explicitly name sibling tools or provide a 'when not to use' clause, so a half-point deduction is applied.

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