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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower. The description still adds real behavior the annotations do not cover: a required BYOK _apiKey and a cost of 1 Apollo credit per enrichment, which matters for agent budgeting decisions.

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?

Front-loaded with the core action and identifier options, then terse cost/BYOK notes. The inline example largely duplicates the schema's examples block, which is slight redundancy but not egregious.

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?

No output schema exists, so the description usefully enumerates returned fields (industry, headcount, revenue, funding, technologies). With full schema coverage and no annotations gaps on safety, this is nearly complete; only routing to sibling tools is missing.

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 schema already documents name, domain, website, linkedin_url, and _apiKey with formats and constraints. The description reinforces the identifier options and BYOK requirement but adds no syntax beyond the schema, making the baseline 3 appropriate.

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 (Enrich) and resource (a single company) and names the three accepted identifiers plus the returned data fields. It implicitly distinguishes itself from apollo_search_organizations by emphasizing 'a single company,' but never names that sibling explicitly.

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?

Provides operational context (BYOK, credit cost, a working example) but no explicit when-to-use guidance against alternatives like apollo_search_organizations or apollo_enrich_person. Usage is only implied by 'single company' vs. search siblings.

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