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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond annotations: the domain must be bare (not a URL), and the returned organization object contains a specific set of fields. It also notes that the returned id is needed for a sibling tool, which is valuable operational context. It doesn't mention rate limits or error behavior, but the annotations carry the main safety burden.

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 compact and front-loaded: the core action and constraint appear in the first sentence, followed by the return shape and routing guidance. Every sentence earns its place, and the sibling references are concise without being verbose.

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 single-parameter, read-only, idempotent tool with a full output schema, the description is complete. It covers the input constraint, the return object, the entry-point use case, and the alternatives. Nothing an agent needs to call it correctly 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 coverage is 100%, so the schema already documents the domain parameter well. The description adds value by reinforcing the bare-domain requirement and clarifying that the parameter is the only one, plus explaining what the return object contains. This goes slightly beyond the schema's example and format guidance, so it earns above the baseline 3.

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 states a specific verb ('Enrich'), a specific resource ('one company by domain'), and the exact input format ('bare domain, not a full URL'). It also distinguishes itself from sibling tools by naming the alternatives for bulk enrichment and full-record retrieval, so an agent can tell it apart without opening schemas.

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 says to use this tool as the entry point when all you have is a domain, and names two alternatives with their conditions: post_apollo_organizations_bulk_enrich for several domains, and get_apollo_organizations_id for the full record including funding and technology detail. This is clear when-to-use and when-not-to-use guidance.

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