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

Annotations already declare read-only, idempotent, open-world, non-destructive, so safety is covered. The description adds genuinely useful behavior the annotations cannot express: expected hit rates (~2 in 3 with company_domain, ~1 in 4 with company_name only) and the high frequency of no-result, which shapes how an agent should plan around failure.

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?

Four sentences, each carrying distinct information: purpose, prerequisite sibling, accuracy expectations, and the validation alternative. Purpose is front-loaded and there is no redundant restatement of the name or title.

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?

There is no output schema, so the description should ideally clarify the shape of a hit versus a miss, and it only implies this via 'No result is common'. Otherwise it covers prerequisites, alternatives, accuracy expectations, and failure handling adequately for a four-parameter 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 coverage is 100%, so the baseline is 3 and the schema already defines all four fields. The description earns extra credit by quantifying the accuracy difference between company_domain and company_name, giving the agent a reason to prefer one optional parameter over the other rather than just repeating the schema's 'Recommended for best accuracy'.

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?

States a specific verb and resource (find a person's work email) plus the inputs it keys on (name and company), and the example use cases (prospect or candidate) frame it concretely. It is clearly separable from siblings like validate_email and linkedin_get_profile, both of which are named.

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?

Explicitly routes the agent: use linkedin_get_profile first when name/company are missing, and use validate_email when an address is already in hand. It also warns that a null result is normal and forbids guessing addresses, which is an explicit when-not-to-do-something instruction.

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